MCKESSON CORP
S-3, 1997-05-02
DRUGS, PROPRIETARIES & DRUGGISTS' SUNDRIES
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<PAGE>
 
      AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON MAY 2, 1997
                                                      REGISTRATION NO. 33-
- - -------------------------------------------------------------------------------
- - -------------------------------------------------------------------------------
                      SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C. 20549
                                ---------------
                                   FORM S-3
                            REGISTRATION STATEMENT
                                     UNDER
                          THE SECURITIES ACT OF 1933

<TABLE> 
<CAPTION> 
<S>                                        <C>                       <C>
      MCKESSON CORPORATION                 DELAWARE                  94-3207296
    MCKESSON FINANCING TRUST               DELAWARE                  52-6841546
    (EXACT NAME OF REGISTRANT   (STATE OF OTHER JURISDICTION OF   (I.R.S. EMPLOYER
  AS SPECIFIED IN ITS CHARTER)   INCORPORATION OR ORGANIZATION) IDENTIFICATION NUMBER)
</TABLE>
 MCKESSON PLAZA, ONE POST STREET, SAN FRANCISCO, CALIFORNIA 94104, (415) 983-
                                     8300
  (ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE, OF
                   REGISTRANT'S PRINCIPAL EXECUTIVE OFFICES)
                                NANCY A. MILLER
                    VICE PRESIDENT AND CORPORATE SECRETARY
                             MCKESSON CORPORATION
 MCKESSON PLAZA, ONE POST STREET, SAN FRANCISCO, CALIFORNIA 94104, (415) 983-
                                     8300
(NAME, ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE,
                             OF AGENT FOR SERVICE)
                                ---------------
                                   COPY TO:
         GREGG A. NOEL, ESQ.                   IVAN D. MEYERSON, ESQ.
 SKADDEN, ARPS, SLATE, MEAGHER & FLOM           MCKESSON CORPORATION
                  LLP                      MCKESSON PLAZA, ONE POST STREET
       300 SOUTH GRAND AVENUE,             SAN FRANCISCO, CALIFORNIA 94104
    LOS ANGELES, CALIFORNIA 90071                  (415) 983-8300
                                ---------------
            (213) 687-5000
       APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC:
    From time to time after this Registration Statement becomes effective.
                                ---------------
  If the only securities being registered on this Form are being offered
pursuant to dividend or interest reinvestment plans, please check the
following box. [_]
  If any of the securities being registered on this Form are to be offered on
a delayed or continuous basis pursuant to Rule 415 under the Securities Act of
1933, as amended (the "Securities Act"), other than securities offered only in
connection with dividend or interest reinvestment plans, please check the
following box. [X]
  If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following
box and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering. [_]
  If this Form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering. [_]
  If delivery of the prospectus is expected to be made pursuant to Rule 434,
please check the following box. [_]
                        CALCULATION OF REGISTRATION FEE
- - -------------------------------------------------------------------------------
- - -------------------------------------------------------------------------------
<TABLE>
<CAPTION>
                                                       PROPOSED
                                                       MAXIMUM       PROPOSED MAXIMUM     AMOUNT OF
       TITLE OF EACH CLASS OF          AMOUNT TO    OFFERING PRICE       AGGREGATE       REGISTRATION
    SECURITIES TO BE REGISTERED      BE REGISTERED   PER SECURITY     OFFERING PRICE         FEE
- - -----------------------------------------------------------------------------------------------------
<S>                                  <C>            <C>            <C>                   <C>
Trust Convertible Preferred
 Securities of McKesson Financing
 Trust..............................   4,000,000     $56.25(1)(2)  $225,000,000.00(1)(2)  $68,181.82
- - -----------------------------------------------------------------------------------------------------
Convertible Subordinated Debentures
 of McKesson Corporation............      (3)             --                --                --
- - -----------------------------------------------------------------------------------------------------
Common Stock of McKesson
 Corporation, $0.01 par value per
 share..............................   2,766,604(4)       --                --                --
Rights to purchase Preferred Stock..   2,766,604(5)       --                --                --
- - -----------------------------------------------------------------------------------------------------
Guarantee(6)........................      --              --                --                --
- - -----------------------------------------------------------------------------------------------------
  Total.............................   6,766,604         100%         $225,000,000.00     $68,181.82
</TABLE>
 
- - -------------------------------------------------------------------------------
- - -------------------------------------------------------------------------------
(1) Estimated solely for the purpose of computing the registration fee in
    accordance with Rule 457(c) of the Securities Act.
(2) Exclusive of accrued interest and distributions, if any.
(3) $200,000,000 in aggregate principal amount of 5% Convertible Junior
    Subordinated Debentures (the "Convertible Debentures") of McKesson
    Corporation (the "Company") were issued and sold to McKesson Financing
    Trust (the "Trust") in connection with the issuance by the Trust of
    4,000,000 of its 5% Trust Convertible Preferred Securities (the
    "Convertible Preferred Securities"). The Convertible Debentures may be
    distributed, under certain circumstances, to the holders of Convertible
    Preferred Securities for no additional consideration.
(4) Such shares of Company Common Stock are issuable upon conversion of the
    Convertible Preferred Securities registered hereunder. This Registration
    Statement also covers such shares as may be issuable pursuant to anti-
    dilution adjustments.
(5) Associated with the Company Common Stock are Rights to purchase Series A
    Preferred Stock that will not be exercisable or evidenced separately from
    the Company Common Stock prior to the occurrence of certain events.
(6) Includes the rights of holders of the Convertible Preferred Securities
    under the Guarantee and certain back-up undertakings as described in the
    Registration Statement. No separate consideration will be received for the
    Guarantee and the back-up undertakings.
  THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT
SHALL FILE A FURTHER AMENDMENT THAT SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(A) OF
THE SECURITIES ACT OF 1933, AS AMENDED, OR UNTIL THE REGISTRATION STATEMENT
SHALL BECOME EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID
SECTION 8(A), MAY DETERMINE.
                                ---------------
- - -------------------------------------------------------------------------------
- - -------------------------------------------------------------------------------

<PAGE>
 
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+INFORMATION CONTAINED HEREIN IS SUBJECT TO COMPLETION OR AMENDMENT. A         +
+REGISTRATION STATEMENT RELATING TO THESE SECURITIES HAS BEEN FILED WITH THE   +
+SECURITIES AND EXCHANGE COMMISSION. THESE SECURITIES MAY NOT BE SOLD NOR MAY  +
+OFFERS TO BUY BE ACCEPTED PRIOR TO THE TIME THE REGISTRATION STATEMENT        +
+BECOMES EFFECTIVE. THIS PROSPECTUS SHALL NOT CONSTITUTE AN OFFER TO SELL OR   +
+THE SOLICITATION OF AN OFFER TO BUY NOR SHALL THERE BE ANY SALE OF THESE      +
+SECURITIES IN ANY STATE IN WHICH SUCH OFFER, SOLICITATION OR SALE WOULD BE    +
+UNLAWFUL PRIOR TO REGISTRATION OR QUALIFICATION UNDER THE SECURITIES LAWS OF  +
+ANY SUCH STATE.                                                               +
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
                    SUBJECT TO COMPLETION, DATED MAY 2, 1997
 
PROSPECTUS
 
                4,000,000 TRUST CONVERTIBLE PREFERRED SECURITIES
                            MCKESSON FINANCING TRUST
                   5% TRUST CONVERTIBLE PREFERRED SECURITIES
          (LIQUIDATION AMOUNT $50 PER CONVERTIBLE PREFERRED SECURITY)
                  GUARANTEED TO THE EXTENT SET FORTH HEREIN BY
 
                              MCKESSON CORPORATION
                                  -----------
  This Prospectus relates to the 5% Trust Convertible Preferred Securities (the
"Convertible Preferred Securities") which represent preferred undivided
beneficial interests in the assets of McKesson Financing Trust, a statutory
business trust formed under the laws of the State of Delaware ("McKesson
Financing Trust" or the "Trust"), and the shares of common stock, par value
$.01 per share ("McKesson Common Stock" or the "Common Stock"), of McKesson
Corporation, a Delaware corporation ("McKesson" or the "Company"), issuable
upon conversion of the Convertible Preferred Securities. The Convertible
Preferred Securities were issued and sold (the "Original Offering") on February
20, 1997 (the "Original Offering Date") to the Initial Purchaser (as defined
herein) and were simultaneously sold by the Initial Purchaser in transactions
exempt from the registration requirements of the Securities Act of 1933, as
amended (the "Securities Act"), in the United States to persons reasonably
believed by the Initial Purchaser to be qualified institutional buyers as
defined in Rule 144A under the Securities Act, to certain qualified
institutional buyers acting on behalf of institutional "accredited investors"
(as defined in Rule 501(a)(1), (2), (3) or (7) under the Securities Act) and
outside the United States to non-U.S. persons in offshore transactions in
reliance on Regulation S under the Securities Act. The Company directly or
indirectly owns all the common securities (the "Common Securities" and,
together with the Convertible Preferred Securities, the "Trust Securities")
representing undivided beneficial interests in the assets of the Trust. The
Trust exists for the sole purpose of issuing the Trust Securities and investing
the proceeds of the sale thereof in 5% Convertible Junior Subordinated
Debentures (the "Convertible Debentures") of McKesson in an aggregate principal
amount equal to the aggregate liquidation amount of the Trust Securities. Upon
an event of default under the Declaration (as defined herein), the holders of
Convertible Preferred Securities will have a preference over the holders of the
Common Securities with respect to payments in respect of distributions and
payments upon redemption, liquidation or otherwise.
 
  The Convertible Preferred Securities and the Company Common Stock issuable
upon conversion of the Convertible Preferred Securities (collectively, the
"Offered Securities") may be offered and sold from time to time by the holders
named herein or by their transferees, pledgees, donees or their successors
(collectively, the "Selling Holders") pursuant to this Prospectus. The Offered
Securities may be sold by the Selling Holders from time to time (i) to or
through underwriters or dealers; (ii) directly to one or more other purchasers;
(iii) through agents on a best-efforts basis or otherwise; or (iv) through a
combination of any such methods of sale. The Offered Securities may be sold
from time to time in one or more transactions at a fixed price or prices, which
may be changed, or at market prices prevailing at the time of sale, at prices
unrelated to such prevailing market prices, or at negotiated prices. See
"Selling Holders" and "Plan of Distribution." If required, the names of any
such agents or underwriters involved in the sale of the Offered Securities and
the applicable agent's commission, dealer's purchase price or underwriter's
discount, if any, will be set forth in an accompanying supplement to this
Prospectus (the "Prospectus Supplement"). The Selling Holders will receive all
of the net proceeds from the sale of the Offered Securities and will pay all
underwriting discounts, selling commissions and transfer taxes, if any,
applicable to any such sale. The Company is responsible for payment of all
other expenses incident to the registration of the Offered Securities. The
Selling Holders and any broker-dealers, agents or underwriters that participate
in the distribution of the Offered Securities may be deemed to be
"underwriters" within the meaning of the Securities Act, and any commission
received by them and any profit on the resale of the Offered Securities
purchased by them may be deemed to be underwriting commissions or discounts
under the Securities Act. See "Plan of Distribution" for a description of
indemnification arrangements.
                                                        (continued on next page)
 
         SEE "RISK FACTORS" BEGINNING ON PAGE 6 FOR CERTAIN INFORMATION
       RELEVANT TO AN INVESTMENT IN THE CONVERTIBLE PREFERRED SECURITIES.
 
                                  -----------
 
THESE SECURITIES  HAVE NOT BEEN APPROVED  OR DISAPPROVED BY THE  SECURITIES AND
 EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS THE SECURITIES
  AND EXCHANGE COMMISSION OR ANY  STATE SECURITIES COMMISSION PASSED UPON THE
  ACCURACY  OR  ADEQUACY  OF  THIS  PROSPECTUS.  ANY  REPRESENTATION  TO  THE
   CONTRARY IS A CRIMINAL OFFENSE.
 
                  The date of this Prospectus is      , 1997.
<PAGE>
 
  Holders of the Convertible Preferred Securities are entitled to receive
cumulative cash distributions at an annual rate of 5% of the liquidation
amount of $50 per Convertible Preferred Security, accruing from the first date
that any Convertible Preferred Securities are issued and payable quarterly in
arrears on March 1, June 1, September 1 and December 1 of each year,
commencing June 1, 1997 ("distributions"). The payment of distributions out of
monies held by McKesson Financing Trust and payments on liquidation of
McKesson Financing Trust or the redemption of Convertible Preferred
Securities, as set forth below, are guaranteed by McKesson (the "Guarantee")
to the extent described herein. The Guarantee covers payments of distributions
and other payments on the Convertible Preferred Securities only if and to the
extent that McKesson Financing Trust has funds available therefor, which will
not be the case unless McKesson has made corresponding payments of interest or
principal or other payments on the Convertible Debentures held by McKesson
Financing Trust. The Guarantee, when taken together with McKesson's
obligations under the Convertible Debentures and the Indenture (as defined
herein) and its obligations under the Declaration, including its liabilities
to pay costs, expenses, debts and obligations of McKesson Financing Trust
(other than with respect to the Trust Securities), provide a full and
unconditional guarantee, to the extent set forth herein, of amounts due on the
Convertible Preferred Securities. See "Risk Factors--Limitations of the
Guarantee."
 
  The obligations of McKesson under the Guarantee are subordinate and junior
in right of payment to all other liabilities of McKesson and pari passu with
the most senior preferred stock issued from time to time, if any, by McKesson.
The obligations of McKesson under the Convertible Debentures are subordinate
and junior in right of payment to all present and future Senior Indebtedness
(as defined herein) of McKesson.
 
  The Convertible Debentures purchased by the Trust may be subsequently
distributed pro rata to holders of the Trust Securities in connection with the
dissolution of the Trust, upon the occurrence of certain events.
 
  Each Convertible Preferred Security is convertible in the manner described
herein at the option of the holder, at any time beginning May 21, 1997 and
prior to the Conversion Expiration Date (as defined herein), into shares of
common stock, par value $.01 per share, of McKesson ("McKesson Common Stock"
or the "Common Stock"), at the rate of .6709 shares of McKesson Common Stock
for each Convertible Preferred Security (equivalent to a conversion price of
$74.53 per share (the "Conversion Price") of McKesson Common Stock), subject
to adjustment in certain circumstances. See "Description of Convertible
Preferred Securities--Conversion Rights." On May 1, 1997, the reported last
sale price of McKesson Common Stock, which is reported under the symbol "MCK"
on the New York Stock Exchange, was $72 1/8 per share.
 
  The distribution rate and the distribution payment dates and other payment
dates for the Convertible Preferred Securities correspond to the interest rate
and interest payment dates and other payment dates of the Convertible
Debentures, which are the sole assets of the Trust. As a result, if principal
and interest are not paid on the Convertible Debentures, no amounts will be
paid on the Convertible Preferred Securities.
 
  So long as McKesson shall not be in default in the payment of interest on
the Convertible Debentures, McKesson has the right to defer payments of
interest on the Convertible Debentures by extending the interest payment
period on the Convertible Debentures at any time for up to 20 consecutive
quarters (each, an "Extension Period"). If interest payments are so deferred,
distributions will continue to accumulate with interest thereon (to the extent
permitted by applicable law) at the distribution rate, compounded quarterly.
During any Extension Period, holders of Convertible Preferred Securities will
be required to include deferred interest income in their gross income for
United States federal income tax purposes in advance of receipt of the cash
distributions with respect to such deferred interest payments. There could be
multiple Extension Periods of varying lengths throughout the term of the
Convertible Debentures. See "Description of the Convertible Debentures--Option
to Extend Interest Payment Period," "Risk Factors--Delay of Interest Payments"
and "United States Federal Income Taxation--Potential Extension of Interest
Payment Period and Original Issue Discount."
 
  The Convertible Debentures are redeemable by McKesson, in whole or in part,
from time to time, on or after March 4, 2000, at the prices set forth herein
(the "Redemption Price"), plus accrued and unpaid interest
 
                                       2
<PAGE>
 
(continued from previous page)

thereon to the date fixed for redemption (the "Redemption Date"). In addition,
in certain circumstances upon the occurrence of a Tax Event (as defined
herein) the Convertible Debentures may be redeemed by McKesson at 100% of the
principal amount thereof plus accrued and unpaid interest thereon. If McKesson
redeems the Convertible Debentures, the Trust must redeem Convertible
Preferred Securities having an aggregate liquidation amount equal to the
aggregate principal amount of the Convertible Debentures so redeemed. See
"Description of the Convertible Preferred Securities--Mandatory Redemption."
The outstanding Convertible Preferred Securities will be redeemed when the
Convertible Debentures mature on June 1, 2027.
 
  Upon the occurrence of a Special Event (as defined herein), unless the
Convertible Debentures are redeemed in the limited circumstances described
herein, the Trust may be dissolved (with the consent of McKesson), with the
result that the Convertible Debentures would be distributed to the holders of
the Convertible Preferred Securities, on a pro rata basis. If McKesson
declines to consent to such dissolution and distribution, McKesson may incur
an obligation to pay additional sums. See "Description of the Convertible
Preferred Securities--Special Event Distribution; Tax Event Redemption" and
"Description of the Convertible Debentures--Additional Sums."
 
  In addition, subject to certain conditions, McKesson has the right at any
time to cause the Trust to be dissolved and cause the Convertible Debentures
to be distributed to the holders of the Convertible Preferred Securities on a
pro rata basis, in lieu of any cash distribution. See "Description of the
Convertible Preferred Securities--Liquidation of Trust and Distribution of
Convertible Debentures to Holders" and "Description of the Convertible
Debentures."
 
  In the event of the involuntary dissolution, winding up or termination of
the Trust, the holders of the Convertible Preferred Securities are entitled to
receive for each Convertible Preferred Security a liquidation amount of $50
plus accrued and unpaid distributions thereon to the date of payment, unless,
in connection with such dissolution, winding up or termination of the Trust,
the Convertible Debentures are distributed to the holders of the Convertible
Preferred Securities. See "Description of the Convertible Preferred
Securities--Liquidation Distribution Upon Dissolution."
 
 
                                       3
<PAGE>
 
  Certain persons participating in this offering may engage in transactions
that stabilize, maintain, or otherwise affect the price of the Offered
Securities. Specifically, the underwriters, if any, may overallot in
connection with the offering, and may bid for, and purchase, shares of the
Offered Securities in the open market. For a description of those activities,
see "Plan of Distribution."
 
  Unless otherwise stated herein or the context otherwise requires, all
references herein to the "principal" of the Convertible Debentures shall be
deemed to include a reference to "and premium, if any."
 
                             AVAILABLE INFORMATION
 
  This Prospectus constitutes a part of a combined Registration Statement on
Form S-3 (together with all amendments and exhibits thereto, the "Registration
Statement") filed by McKesson and McKesson Financing Trust with the Securities
and Exchange Commission (the "Commission") under the Securities Act of 1933,
as amended (the "Securities Act"), with respect to the Offered Securities.
This Prospectus does not contain all of the information set forth in such
Registration Statement, certain parts of which are omitted in accordance with
the rules and regulations of the Commission, although it does include a
summary of the material terms of the Indenture and the Declaration (each as
defined herein). Reference is made to such Registration Statement and to the
exhibits relating thereto for further information with respect to the Company,
McKesson Financing Trust and the Offered Securities. Any statements contained
herein concerning the provisions of any document filed as an exhibit to the
Registration Statement or otherwise filed with the Commission or incorporated
by reference herein are not necessarily complete, and, in each instance,
reference is made to the copy of such document so filed for a more complete
description of the matter involved. Each such statement is qualified in its
entirety by such reference.
 
  The Company is subject to the informational requirements of the Securities
Exchange Act of 1934, as amended (the "Exchange Act"), and in accordance
therewith files reports, proxy statements and other information with the
Commission. Such reports, proxy statements and other information filed by the
Company with the Commission can be inspected and copied at the Commission's
Public Reference Room at 450 Fifth Street, N.W., Washington, D.C. 20549, or at
the public reference facilities of the regional offices in Chicago and New
York. The addresses of these regional offices are as follows: 500 West Madison
Street, Chicago, Illinois 66061, and 7 World Trade Center, 13th Floor, New
York, New York 10048. Copies of such material also can be obtained by mail
from the Public Reference Section of the Commission at 450 Fifth Street, N.W.,
Washington, D.C. 20549, upon payment of the fees prescribed by the rules and
regulations of the Commission. Reports, proxy statements, and other
information concerning the Company may also be inspected at the offices of the
New York Stock Exchange, Inc. at 20 Broad Street, New York, New York 10005 and
at the offices of the Pacific Exchange, Inc. at 301 Pine Street, San
Francisco, California 94014. The Company's Common Stock is listed on both
exchanges. Such material may also be accessed electronically by means of the
Commission's home page on the Internet at http://www.sec.gov.
 
  No separate financial statements of the Trust have been included or
incorporated by reference herein. The Company and the Trust do not consider
that such financial statements would be material to holders of the Convertible
Preferred Securities because (i) all of the voting securities of the Trust
will be owned, directly or indirectly, by the Company, a reporting company
under the 1934 Act, (ii) the Trust is a special purpose entity, has no
operating history, has no independent operations and is not engaged in, and
does not propose to engage in, any activity other than issuing Trust
Securities representing undivided beneficial interests in the assets of the
Trust and investing the proceeds thereof in Convertible Debentures issued by
the Company and (iii) McKesson's obligations described herein under the
Declaration, the Guarantee with respect to the Convertible Preferred
Securities issued by the Trust, the Convertible Debentures purchased by the
Trust and the Indenture, taken together, constitute a full and unconditional
guarantee of payments due on the Convertible Preferred Securities of the
Trust. See "McKesson Financing Trust," "Description of the Convertible
Preferred Securities," "Description of the Guarantee" and "Description of the
Convertible Debentures." The Trust is a statutory business trust formed under
the laws of the state of Delaware. The Company, as of the date of this
Prospectus, owns all of the beneficial interests in the Trust.
 
                                       4
<PAGE>
 
                INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE
 
  There are hereby incorporated by reference in this Prospectus the following
documents previously filed or to be filed by the Company with the Commission
pursuant to the Exchange Act:
 
  1. Annual Report on Form 10-K for the fiscal year ended March 31, 1996, as
amended by Amendment No. 1 on Form 10-K/A, filed on February 13, 1997 to
reflect Armor All (as defined herein) and Millbrook (as defined herein) as
discontinued operations (the "Form 10-K").
 
  2. Quarterly Reports on Form 10-Q for the quarters ended June 30, 1996, as
amended by Amendment No. 1 on Form 10-Q/A, filed on February 13, 1997 to
reflect Armor All and Millbrook as discontinued operations (the "June Form 10-
Q"), September 30, 1996, as amended by Amendment No. 1 on Form 10-Q/A, filed
on February 13, 1997 to reflect Armor All and Millbrook as discontinued
operations (the "September Form 10-Q") and December 31, 1996 (the "December
Form 10-Q").
 
  3. Current Reports on Form 8-K dated April 8, 1996, April 30, 1996, October
9, 1996 (as amended by Amendment No. 1 on Form 8-K/A filed December 20, 1996,
excluding Exhibit 99 thereto), November 22, 1996 (as amended by Amendment No.
1 on Form 8-K/A, filed on January 21, 1997, as further amended by Amendment
No. 2 on Form 8-K/A, filed on April 28, 1997), December 10, 1996, January 13,
1997, February 5, 1997, February 12, 1997, February 24, 1997 and April 7,
1997.
 
  All documents filed by the Company pursuant to Section 13(a), 13(c), 14 or
15(d) of the 1934 Act subsequent to the date of this Prospectus and prior to
the termination of the offering of the Convertible Preferred Securities
offered hereby shall be deemed to be incorporated by reference in this
Prospectus and to be part hereof from the date of filing of such documents.
Any statement contained herein or in a document incorporated or deemed to be
incorporated by reference herein shall be deemed to be modified or superseded
for purposes of this Prospectus to the extent that a statement contained
herein or in any other subsequently filed document which also is or is deemed
to be incorporated by reference herein modifies or supersedes such statement.
Any such statement so modified or superseded shall not be deemed, except as so
modified or superseded, to constitute a part of this Prospectus.
 
  The Company will provide without charge to each person upon the written or
oral request of such person, a copy of any or all of the foregoing documents
incorporated herein by reference, other than exhibits to such documents
(unless such exhibits are specifically incorporated by reference into such
documents). Requests for such documents shall be directed to Nancy A. Miller,
Vice President and Corporate Secretary, McKesson Corporation, McKesson Plaza,
One Post Street, San Francisco, California 94104 (telephone number (415) 983-
8301).
 
               SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS
 
  Certain of the matters discussed under the captions "Risk Factors,"
"Financial Review," "The Company" and elsewhere in this Prospectus or in the
information incorporated by reference herein may constitute forward-looking
statements within the meaning of the Private Securities Litigation Reform Act
of 1995 (the "Reform Act") and as such may involve known and unknown risks,
uncertainties and other factors that may cause the actual results, performance
or achievements of McKesson to be materially different from any future
results, performance or achievements expressed or implied by such forward-
looking statements. Some of the factors that may cause such material
differences are set forth herein or attached hereto under the captions "Risk
Factors" and "Financial Review."
 
                                       5
<PAGE>
 
                                 RISK FACTORS
 
  Prospective purchasers of Convertible Preferred Securities should carefully
review the information contained elsewhere and incorporated by reference in
this Prospectus and should particularly consider the following matters.
Certain statements set forth below under this caption constitute "forward-
looking statements" within the meaning of the Reform Act. See "Special Note
Regarding Forward-Looking Statements" above for additional factors relating to
such statements.
 
SUBORDINATE RANKING OF OBLIGATIONS UNDER THE GUARANTEE AND CONVERTIBLE
DEBENTURES
 
  McKesson's obligations under the Guarantee are subordinate and junior in
right of payment to all liabilities of McKesson (other than any other
obligations that may be made pari passu expressly by their terms) and pari
passu in right of payment with the most senior preferred stock issued, from
time to time, if any, by McKesson. The obligations of McKesson under the
Convertible Debentures are subordinate and junior in right of payment to all
present and future Senior Indebtedness of McKesson. No payment of principal
(including redemption payments, if any), premium, if any, or interest on the
Convertible Debentures may be made if (i) the payment of principal, premium,
if any, interest or any other payment due on any Senior Indebtedness of
McKesson is not paid when due and any applicable grace period with respect to
such default has ended with such default not having been cured or waived or
ceasing to exist or (ii) the maturity of any Senior Indebtedness has been
accelerated because of a default and such acceleration has not been rescinded.
There are no terms in the Convertible Preferred Securities, the Convertible
Debentures or the Guarantee that limit McKesson's ability to incur additional
indebtedness, including indebtedness that ranks senior to the Convertible
Debentures and the Guarantee, or to grant security interests to secure
outstanding or new indebtedness. There was approximately $825 million of
Senior Indebtedness outstanding as of March 31, 1997. See "Description of the
Guarantee--Status of the Guarantee" and "Description of the Convertible
Debentures--Subordination."
 
LIMITATIONS OF THE GUARANTEE
 
  The Guarantee Trustee (as defined herein) holds the Guarantee for the
benefit of the holders of the Convertible Preferred Securities. Under the
Guarantee, McKesson irrevocably and unconditionally guarantees on a
subordinated basis to the holders of the Convertible Preferred Securities, to
the extent not paid by the Trust, the payment in full of (i) all accrued and
unpaid distributions that are required to be paid on the Convertible Preferred
Securities to the extent the Trust has funds available therefor, (ii) the
Redemption Price plus accrued and unpaid distributions with respect to any
Convertible Preferred Securities called for redemption by the Trust, to the
extent the Trust has funds available therefor and (iii) upon a voluntary or
involuntary dissolution, winding-up or termination of the Trust (other than in
connection with the distribution of Convertible Debentures to the holders of
Convertible Preferred Securities or the redemption of all the Convertible
Preferred Securities), the lesser of (a) the aggregate of the liquidation
amount and all accrued and unpaid distributions on the Convertible Preferred
Securities to the date of the payment to the extent the Trust has funds
available therefor or (b) the amount of assets of the Trust remaining
available for distribution to holders of the Convertible Preferred Securities
in liquidation of the Trust. Because the Guarantee is limited by the amount of
the funds in the Trust, if McKesson were to default on its obligation to pay
amounts payable on the Convertible Debentures, the Trust would lack available
funds for the payment of distributions or amounts payable on redemption of the
Convertible Preferred Securities or otherwise, and, in such event, holders of
the Convertible Preferred Securities would not be able to rely upon the
Guarantee for payment of such amounts. Instead, holders of the Convertible
Preferred Securities would rely on the enforcement (1) by the Institutional
Trustee (as defined herein) of its rights as registered holder of the
Convertible Debentures against McKesson pursuant to the terms of the
Convertible Debentures or (2) by such holder of its right of Direct Action (as
defined herein) against McKesson as described below to enforce payments on the
Convertible Debentures. See "Description of the Guarantee--Events of Default."
The Declaration provides that each holder of Convertible Preferred Securities,
by acceptance thereof, agrees to the provisions of the Guarantee, including
the subordination provisions thereof, and the Indenture.
 
 
                                       6
<PAGE>
 
LIMITATION OF ENFORCEMENT OF CERTAIN RIGHTS BY HOLDERS OF CONVERTIBLE
PREFERRED SECURITIES
 
  If (i) McKesson Financing Trust fails to pay distributions in full on the
Convertible Preferred Securities (other than pursuant to a deferral pursuant
to an Extension Period) or (ii) a Declaration Event of Default (as defined
herein) occurs and is continuing, then the holders of Convertible Preferred
Securities would rely on the enforcement by the Institutional Trustee of its
rights as a holder of the Convertible Debentures against McKesson. In
addition, the holders of a majority in liquidation amount of the Convertible
Preferred Securities have the right to direct the time, method, and place of
conducting any proceeding for any remedy available to the Institutional
Trustee or to direct the exercise of any trust or power conferred upon the
Institutional Trustee under the Declaration, including the right to direct the
Institutional Trustee to exercise the remedies available to it as a holder of
the Convertible Debentures. If the Institutional Trustee fails to enforce its
rights under the Convertible Debentures, a holder of Convertible Preferred
Securities may institute a legal proceeding directly against McKesson to
enforce the Institutional Trustee's rights under the Convertible Debentures
without first instituting any legal proceeding against the Institutional
Trustee or any other person or entity. Notwithstanding the foregoing, if a
Declaration Event of Default has occurred and is continuing and such event is
attributable to the failure of McKesson to pay interest or principal on the
Convertible Debentures on the date such interest or principal is otherwise
payable (or in the case of redemption, on the Redemption Date), then a holder
of Convertible Preferred Securities may directly institute a proceeding for
enforcement of payment to such holder of the principal of or interest on the
Convertible Debentures having a principal amount equal to the aggregate
liquidation amount of the Convertible Preferred Securities of such holder (a
"Direct Action") on or after the respective due date specified in the
Convertible Debentures. In connection with such Direct Action, McKesson will
be subrogated to the rights of such holder of Convertible Preferred Securities
under the Declaration to the extent of any payment made by McKesson to such
holder of Convertible Preferred Securities in such Direct Action. The holders
of Convertible Preferred Securities will not be able to exercise directly any
other remedy available to the holders of Convertible Debentures. See
"Description of the Convertible Preferred Securities--Declaration Events of
Default."
 
DELAY OF INTEREST PAYMENTS
 
  So long as McKesson shall not be in default in the payment of interest on
the Convertible Debentures, McKesson has the right under the Indenture to
defer payments of interest on the Convertible Debentures by extending the
interest payment period at any time, and from time to time, on the Convertible
Debentures. As a consequence of such an extension, quarterly distributions on
the Convertible Preferred Securities would be deferred by the Trust during any
such Extension Period. Prior to the termination of any such Extension Period,
McKesson may further extend such Extension Period; provided, that such
Extension Period, together with all such previous and further extensions
thereof, may not exceed 20 consecutive quarters or extend beyond the maturity
of the Convertible Debentures. Upon the termination of any Extension Period
and the payment of all amounts then due, McKesson may commence a new Extension
Period, subject to the above requirements. See "Description of the Convertible
Preferred Securities--Distributions" and "Description of the Convertible
Debentures--Option to Extend Interest Payment Period."
 
  Should McKesson exercise its right to defer payments of interest by
extending the interest payment period, each holder of Convertible Preferred
Securities will continue to accrue interest income (as original issue discount
("OID")) in respect of the deferred stated interest allocable to its share of
Convertible Preferred Securities for United States federal income tax
purposes. As a result, each such holder of Convertible Preferred Securities
will include such income in gross income for United States federal income tax
purposes in advance of the receipt of cash attributable thereto, and will not
receive the cash from McKesson Financing Trust related to such income if such
holder disposes of its Convertible Preferred Securities prior to the record
date on which distributions of such amounts are made. McKesson has no current
intention of exercising its right to defer payments of interest by extending
the interest payment period of the Convertible Debentures. However, should
McKesson elect to exercise such right in the future, the market price of the
Convertible Preferred Securities is likely to be affected. A holder that
disposes of its Convertible Preferred Securities during an Extension Period,
therefore, might not receive the same return on its investment as a holder
that continues to hold its Convertible Preferred Securities.
 
                                       7
<PAGE>
 
In addition, as a result of the existence of McKesson's right to defer
interest payments, the market price of the Convertible Preferred Securities
(which represent an undivided beneficial interest in the Convertible
Debentures) may be more volatile than other OID securities that do not have
such interest deferral rights. See "United States Federal Income Taxation--
Potential Extension of Interest Payment Period and Original Issue Discount."
 
PROPOSED TAX LEGISLATION
 
  On February 6, 1997, as part of President Clinton's Fiscal 1998 Budget
Proposal, the United States Treasury Department proposed legislation that
would, among other things, deny an issuer a deduction for United States
federal income tax purposes for the payment of interest on instruments with
characteristics similar to the Convertible Debentures. If the proposed
legislation were enacted in its current form, it is not expected to apply to
the Convertible Debentures since the proposed effective date for this
provision is the date of first Congressional committee action. There can be no
assurances, however, that the proposed legislation, if enacted, or similar
legislation enacted after the date hereof, would not adversely affect the tax
treatment of the Convertible Debentures, resulting in a Tax Event (as defined
herein) which would allow the Company to redeem the Convertible Preferred
Securities. See "Description of the Convertible Preferred Securities--Special
Event Distribution; Tax Redemption."
 
SPECIAL EVENT DISTRIBUTION; TAX EVENT REDEMPTION
 
  Upon the occurrence of a Special Event (as defined herein), McKesson
Financing Trust could be dissolved (with the consent of McKesson), except in
the limited circumstance described below, with the result that the Convertible
Debentures would be distributed to the holders of the Trust Securities in
connection with the liquidation of the Trust. In certain circumstances,
McKesson would have the right to redeem the Convertible Debentures, in whole
or in part, in lieu of a distribution of the Convertible Debentures by the
Trust, in which event the Trust would redeem the Trust Securities on a pro
rata basis to the same extent as the Convertible Debentures are redeemed by
McKesson. See "Description of the Convertible Preferred Securities--Special
Event Distribution; Tax Event Redemption."
 
  Under current United States federal income tax law, a distribution of
Convertible Debentures upon the dissolution of McKesson Financing Trust would
not be a taxable event to holders of the Convertible Preferred Securities.
However, a dissolution of McKesson Financing Trust in which holders of the
Convertible Preferred Securities receive cash would be a taxable event to such
holders. See "United States Federal Income Taxation--Receipt of Convertible
Debentures or Cash Upon Liquidation of the Trust."
 
  There can be no assurance as to the market prices for the Convertible
Preferred Securities or the Convertible Debentures that may be distributed in
exchange for Convertible Preferred Securities if a dissolution or liquidation
of the Trust were to occur. Accordingly, the Convertible Preferred Securities
that an investor may purchase, whether pursuant to the offer made hereby or in
the secondary market, or the Convertible Debentures that a holder of
Convertible Preferred Securities may receive on dissolution and liquidation of
the Trust, may trade at a discount to the price that the investor paid to
purchase the Convertible Preferred Securities offered hereby. Because holders
of Convertible Preferred Securities may receive Convertible Debentures upon
the occurrence of a Special Event, prospective purchasers of Convertible
Preferred Securities are also making an investment decision with regard to the
Convertible Debentures and should carefully review all the information
regarding the Convertible Debentures contained herein. See "Description of the
Convertible Preferred Securities--Special Event Distribution; Tax Event
Redemption" and "Description of the Convertible Debentures--General."
 
ABSENCE OF VOTING RIGHTS
 
  Generally, holders of the Convertible Preferred Securities do not have any
voting rights with respect to McKesson's governance, nor are they entitled to
vote to appoint, remove or replace, or to increase or decrease the number of,
MFT Trustees (as defined herein), which voting rights are vested exclusively
in the holder of the Common Securities. See "Description of the Convertible
Preferred Securities--Voting Rights."
 
                                       8
<PAGE>
 
TRADING PRICE
 
  The Convertible Preferred Securities may trade at a price that does not
accurately reflect the value of accrued but unpaid interest (or OID if the
Convertible Debentures are treated as having been issued, or reissued, with
OID) with respect to the underlying Convertible Debentures. A holder who
disposes of his Convertible Preferred Securities will be required to include
in ordinary income (i) any portion of the amount realized that is attributable
to such accrued but unpaid interest to the extent not previously included in
income or (ii) any amount of OID, in either case, that has accrued on his pro
rata share of the underlying Convertible Debentures during the taxable year of
sale through the date of disposition. Any such income inclusion will increase
the holder's adjusted tax basis in his Convertible Preferred Securities
disposed of. To the extent that the amount realized in the sale is less than
the holder's adjusted tax basis, a holder will recognize a capital loss.
Subject to certain limited exceptions, capital losses cannot be applied to
offset ordinary income for United States federal income tax purposes.
 
RISKS GENERALLY ASSOCIATED WITH ACQUISITIONS
 
  An element of the Company's growth strategy is to pursue strategic
acquisitions that either expand or complement the Company's business.
Acquisitions involve a number of special risks, including the diversion of
management's attention to the assimilation of the operations from other
business concerns, difficulties in the integration of operations and systems,
the assimilation and retention of the personnel of the acquired companies,
challenges in retaining the acquired business' customers and potential adverse
short-term effects on the Company's operating results. In addition, the
Company may require additional debt or equity financing for future
acquisitions, which may not be available on terms favorable to the Company, if
at all. The inability of the Company to successfully finance, complete and
integrate strategic acquisitions in a timely manner could have an adverse
impact on the Company's results of operations and its ability to effect a
portion of its growth strategy.
 
CHANGING UNITED STATES HEALTHCARE ENVIRONMENT
 
  In recent years, the healthcare industry has undergone significant change
driven by various efforts to reduce costs, including potential national
healthcare reform, trends toward managed care, cuts in Medicare, consolidation
of pharmaceutical and medical/surgical supply distributors and the development
of large, sophisticated purchasing groups. The Company cannot predict whether
any healthcare reform efforts will be enacted and what effect or to what
extent any such reforms may have on the Company, its practices and products or
its customers and suppliers. Changes in governmental support of healthcare
services, the method by which such services are delivered, the prices for such
services or other legislation or regulations governing such services or
mandated benefits may have a material adverse effect on the Company's results
of operations.
 
                                       9
<PAGE>
 
                                  THE COMPANY
 
  McKesson is the largest health care supply management company in
North America. The Company also develops and manages innovative marketing
programs for drug manufacturers and, through McKesson Water Products Company,
processes and markets pure drinking water.
 
  The Company's objective is to become the world leader in health care supply
and comprehensive pharmaceutical management across the entire supply chain,
from manufacturer to patient. In pursuit of this goal, the Company has
completed a number of acquisitions in its core health care business. Since
late 1995, the Company has acquired General Medical Inc. ("General Medical"),
a leading distributor of medical and surgical supplies to the acute care,
physician care and extended care markets, the drug distribution business of
FoxMeyer Corporation ("FoxMeyer"), Automated Healthcare, Inc. ("AHI"), a
manufacturer of automated drug dispensing equipment for hospitals, and Ogden
BioServices Corporation (now "McKesson Bioservices Corporation"), a provider
of support services to government and commercial organizations engaged in drug
research and development.
 
  The Company conducts its operations through two operating business segments
which generated annual sales in fiscal 1996 of $9.95 billion, approximately
97% of which were generated by the Health Care Services segment and
approximately 3% of which were generated primarily by McKesson's Water
Products (as hereinafter defined) business. In fiscal 1996, operating profits
for the Health Care Services business and the Water Products business were
$206.1 million and $39.6 million, respectively.
 
  The principal executive offices of the Company are located at McKesson
Plaza, One Post Street, San Francisco, California, 94104, and the telephone
number is (415) 983-8300.
 
RECENT ACQUISITIONS AND DISPOSITIONS
 
  McKesson has recently undertaken several initiatives to further focus the
Company on its core health care business:
 
  .  In March 1997, McKesson disposed of Millbrook Distribution Services Inc.
     ("Millbrook") for an amount on an after-tax basis which approximates
     Millbrook's book value. Millbrook is reflected as a discontinued
     operation in the Company's financial statements. Millbrook is engaged in
     distributing health and beauty care products, general merchandise, and
     specialty foods to retail stores.
 
  .  In February 1997, McKesson acquired General Medical, the largest multi-
     market distributor of medical and surgical supplies, for $775 million.
 
  .  In December 1996, the Company disposed of its 55% equity interest in
     Armor All Products Corporation ("Armor All"), a non-health care business.
 
  .  In November 1996, the Company acquired FoxMeyer out of bankruptcy for
     approximately $600 million.
 
  .  In April 1996, the Company acquired AHI, a business that specializes in
     centralized robotic pharmaceutical dispensing systems for hospitals, for
     $65 million.
 
  .  In December 1995, the Company acquired McKesson Bioservices Corporation,
     a business that provides product marketing and support services for the
     pharmaceutical industry, for approximately $20 million.
 
MCKESSON HEALTH CARE SERVICES
 
  Through its Health Care Services segment, the Company is the largest
distributor of ethical and proprietary drugs and health and beauty care
products in North America, generating approximately 84% of the Company's
operating profits from continuing operations in fiscal 1996. The Company is
the market leader in its core U.S. drug distribution business. U.S. health
care operations also include Healthcare Delivery Systems, Inc. ("HDS") and
McKesson Bioservices Corporation, through which the Company provides marketing
and other support services to drug manufacturers, AHI, a business that
specializes in automated pharmaceutical dispensing systems for hospitals, and
Zee Medical, Inc., a distributor of first-aid products and supplies to
industrial and commercial customers.
 
                                      10
<PAGE>
 
International operations include Medis Health and Pharmaceutical Services
Inc., a wholly-owned subsidiary and the largest drug distributor in Canada,
and the Company's 22.7% equity interest in Nadro, S.A. de C.V., the largest
drug distributor in Mexico.
 
  The Company's domestic distribution operations supply drugs and health and
beauty care products to independent and chain drug stores, hospitals,
alternate-site facilities, food stores and mass merchandisers in all 50
states. Using the names "Economost" and "Econolink" and a number of related
service marks, the Company has promoted electronic order entry systems and a
wide range of computerized merchandising and asset management services for
drug retailers and hospitals. The Company also supplies computer-based
practice management systems to drug retailers. The Company believes that its
financial strength, purchasing leverage, nationwide network of distribution
centers, and advanced logistics and information technologies provide
competitive advantages to its drug distribution operations. For example, the
Company uses Acumax(R), a computerized bar-code scanning system, to track
items in its warehouses. Acumax enables the Company to achieve order filling
and inventory accuracy levels of more than 99%, ensuring that the right
product arrives at the right time and place for both the Company's customers
and their patients.
 
  Health Care Services serves three primary customer segments: retail
independent pharmacies, retail chains and institutional providers (including
hospitals, health care facilities and pharmacy service operators) which
represented approximately 41%, 30%, and 21%, respectively, of U.S. Health Care
Services revenues for fiscal 1996. A fourth customer category is
pharmaceutical manufacturers, which is managed by McKesson's Pharmaceutical
and Retail Services Business group.
 
    INDEPENDENT PHARMACIES. In addition to distribution services, the Company
  provides value added services to independent retail pharmacies through
  management information systems, including inventory management, electronic
  billing, current pricing and other financial management offerings. In
  February 1996, McKesson launched the OmniLinkSM centralized pharmacy
  technology platform and the associated CareMaxSM network of independent
  pharmacies. The combined offering links independent pharmacies, creating a
  "virtual chain" for contracting with pharmaceutical suppliers and managed
  care organizations. As of December 31, 1996, OmniLink had been installed in
  over 1,600 pharmacies.
 
    OmniLink offers pharmacies streamlined transaction processing through
  OmniLink's connectivity with managed care organizations, while promoting
  compliance with managed care formularies and appropriate reimbursement from
  managed care plans. The service also improves cash flow for pharmacies and
  enhances pharmacy revenues through programs such as 24-hour advanced
  funding of third-party reimbursements, prescription refill reminders,
  patient direct marketing and distribution of coupons and samples for over-
  the-counter products.
 
    The Company currently has two pharmacy programs for independent
  pharmacies--Valu-Rite(R), a voluntary cooperative program, and Health
  Mart(R), a franchise program. Through Valu-Rite, the Company provides its
  independent U.S. retail drug store customers with a common marketing
  identity, group advertising, purchasing programs, promotional merchandise
  and access to a pharmacy provider network. At December 31, 1996, over 5,200
  stores were participating in the Valu-Rite program. Through Health Mart,
  acquired as part of FoxMeyer, the Company provides its community
  pharmacists with a franchise program. Currently, Health Mart has
  approximately 700 franchisees. Together, Valu-Rite and Health Mart
  pharmacies comprise approximately 20% of the nation's independent retail
  pharmacies.
 
    RETAIL CHAINS. Retail drug chains do business with the Company in three
  ways: primary sourcing, secondary sourcing and dock-to-dock (warehousing).
  In primary sourcing, a chain depends on the Company to supply its
  logistics, warehousing and contract administration functions, much as the
  Company performs primary distribution for all other retail customers. In
  secondary sourcing, the Company "backs up" the chains' own warehouses with
  deliveries on an as-needed basis. In dock-to-dock, the Company transfers
  large-quantity (bulk) shipments from manufacturers to chains and provides
  billing services.
 
    INSTITUTIONAL BUSINESS. The Company, through its McKesson Health Systems
  unit, provides drug distribution services, and related logistics and
  management information systems support, to the institutional
 
                                      11
<PAGE>
 
  market, which includes hospitals, alternate-sites and integrated health
  networks. The acquisition of FoxMeyer strengthened the Company's position
  in the institutional marketplace. Similarly, the completion of the
  acquisition of General Medical further enhances the Company's
  competitiveness, particularly in the fast-growing alternate-site segment.
 
    MANUFACTURERS. Pharmaceutical and Retail Services develops innovative
  marketing and distribution services to build and sustain sales for
  manufacturers' pharmaceutical products. Through its HDS unit, this group
  operates integrated systems for specialized delivery of biotech and other
  high-cost pharmaceutical therapies. These systems manage manufacturer cost
  and information requirements through financial assistance programs for
  patients, reimbursement support and patient advocacy programs, product hot-
  lines, pharmacy-based sampling and physician and patient information
  programs. These services are also provided to manufacturers on a stand-
  alone basis outside of integrated service systems. Through McKesson
  Bioservices Corporation, this group also provides support services to
  commercial, non-profit and governmental organizations engaged in drug
  development and biomedical research including biological repository
  management, clinical trials support and regulatory process management
  services.
 
    McKesson also provides a key service to drug manufacturers with McKesson
  Select GenericsSM, an enhancement of the Company's Multi-Source Complete(R)
  generic drug program which was launched in May 1996. Through the Select
  Generics program, retail customers have access to a broad line of over
  1,300 generic items, and single suppliers are chosen for each item, thereby
  offering to manufacturers the advantage of exclusivity and compliance.
 
GENERAL MEDICAL ACQUISITION
 
  On February 21, 1997, McKesson acquired General Medical for approximately
$775 million, including $347 million for the equity, half in the Company's
Common Stock and half in cash, and the assumption of approximately $428
million in debt. The acquisition of General Medical extends the Company's
product line to include medical and surgical supplies in addition to the drugs
and health and beauty care products it currently distributes. The combination
of McKesson and General Medical creates a strong force to address the
increasingly complex clinical supply needs of physicians, extended-care
facilities and integrated health care networks.
 
  General Medical is the nation's leading supplier of medical-surgical
supplies to the full range of alternate-site health care facilities, including
physicians and clinics (primary care), long-term care and home-care sites
(extended care), and is the third largest distributor of medical-surgical
supplies to hospitals. In the year ended December 31, 1995, General Medical
had revenues of approximately $1.5 billion, of which 58% were derived from the
acute care market, 31% from primary care and 11% from extended care. In
addition to marketing to each market segment separately, General Medical
emphasizes sales to these three market segments through integrated health care
networks which operate health care facilities across the market spectrum.
 
  General Medical distributes a broad array of products, comprising
approximately 130,000 products supplied by over 4,000 medical and surgical
product manufacturers, through a 700-person sales force to more than
200,000 care providers nationwide, including 500 account managers calling on
physicians. Additionally, General Medical offers a variety of value-added
services to its customers, particularly in the area of cost containment and
inventory management. The acquisition of General Medical is a major step
forward in solidifying the Company's position as the world leader in health
care supply management.
 
FOXMEYER ACQUISITION
 
  Prior to its acquisition by the Company, FoxMeyer's drug distribution
business was the fourth largest in the United States. The acquisition of
FoxMeyer pairs the Company's financial capabilities and information technology
expertise with the substantial customer base of FoxMeyer and strengthens the
Company's position in all three customer segments (health care institutions,
retail independents and retail chains). The acquisition also gives the Company
access to new customers and opportunities for consolidation economics,
particularly cost reduction and distribution network reconfiguration.
 
 
                                      12
<PAGE>
 
MCKESSON WATER PRODUCTS COMPANY
 
  McKesson Water Products Company ("Water Products") is a leading provider in
the $3.4 billion bottled water industry in the United States. Except in the
State of Washington, it is the largest bottled water company in the geographic
markets in which it competes. In fiscal 1996, Water Products generated
approximately $40 million in pretax operating profit, and its operating margin
was 15%. Water Products is primarily engaged in the processing and sale of
bottled drinking water delivered to more than 500,000 homes and businesses
under its Sparkletts(R), Alhambra(R), and Crystal(TM) brands in California,
Arizona, Nevada, Oklahoma, Washington and Texas. It also sells packaged water
through retail stores in approximately 40 states.
 
                                USE OF PROCEEDS
 
  The Selling Holders will receive all of the proceeds from the sale of the
Offered Securities. Neither the Company nor the Trust will will receive any
proceeds from the sale of the Offered Securities.
 
                             ACCOUNTING TREATMENT
 
  The financial statements of the Trust will be consolidated with McKesson's
financial statements, with the Preferred Securities accounted for as minority
interests and captioned in the consolidated balance sheet as "McKesson-
obligated mandatorily redeemable preferred securities of subsidiary grantor
trust whose sole assets are junior subordinated debentures of McKesson."
 
                      RATIO OF EARNINGS TO FIXED CHARGES
                                  (UNAUDITED)
 
  The following table sets forth the Company's ratio of earnings to fixed
charges on a historical basis for each of the five fiscal years in the period
ended March 31, 1996, and for each of the nine months ended December 31, 1996
and December 31, 1995. The deficiency of earnings to fixed charges for fiscal
1995 totaled $0.7 million.
 
<TABLE>
<CAPTION>
                                                                 NINE MONTHS
                               FISCAL YEAR ENDED MARCH 31,    ENDED DECEMBER 31
                              ------------------------------- -----------------
                              1996   1995   1994  1993  1992    1996     1995
                              ----- ------  ----- ----- ----- -------- --------
<S>                           <C>   <C>     <C>   <C>   <C>   <C>      <C>
Ratio of Earnings to Fixed
 Charges..................... 4.71x (0.01x) 3.42x 2.97x 1.45x    0.43x    4.40x
</TABLE>
 
  The ratio of earnings to fixed charges was computed by dividing fixed
charges (interest expense including the interest portion of capital and
operating leases) into earnings available for fixed charges (income from
continuing operations plus taxes on income and fixed charges).
 
                                      13
<PAGE>
 
                           MCKESSON FINANCING TRUST
 
  McKesson Financing Trust is a statutory business trust formed under Delaware
law pursuant to (i) a Declaration of Trust, as amended by an Amended and
Restated Declaration of Trust (the "Declaration"), executed by McKesson, as
sponsor (the "Sponsor"), and the trustees of McKesson Financing Trust (the
"MFT Trustees") and (ii) the filing of a certificate of trust with the
Secretary of State of the State of Delaware. McKesson owns Common Securities
in an aggregate liquidation amount equal to 3% of the total capital of
McKesson Financing Trust. The assets of the Trust consist solely of the
Convertible Debentures. McKesson Financing Trust exists for the exclusive
purposes of (i) issuing the Trust Securities representing undivided beneficial
interests in the assets of the Trust, (ii) investing the gross proceeds of the
Trust Securities in the Convertible Debentures, and (iii) engaging in only
those other activities necessary or incidental thereto.
 
  Pursuant to the Declaration, the number of MFT Trustees is initially five.
Three of the MFT Trustees (the "Regular Trustees") are persons who are
employees or officers of or who are affiliated with McKesson. The fourth
trustee is an entity that maintains its principal place of business in the
state of Delaware (the "Delaware Trustee"). The fifth trustee (the
"Institutional Trustee") is a financial institution that is unaffiliated with
McKesson and serves as institutional trustee under the Declaration and acts as
indenture trustee under the Declaration for the purposes of compliance with
the provisions of the Trust Indenture Act of 1939, as amended (the "Trust
Indenture Act"). The First National Bank of Chicago, is the Institutional
Trustee until removed or replaced by the holder of the Common Securities. The
First National Bank of Chicago also acts as trustee (the "Guarantee Trustee")
under the Guarantee and as trustee (the "Debt Trustee") under the Indenture.
First Chicago Delaware Inc., an affiliate of the Institutional Trustee, acts
as Delaware Trustee. See "Description of the Convertible Preferred
Securities--Voting Rights."
 
  The Institutional Trustee holds title to the Convertible Debentures for the
benefit of the holders of the Trust Securities and the Institutional Trustee
has the power to exercise all rights, powers and privileges under the
Indenture as the holder of the Convertible Debentures. In addition, the
Institutional Trustee maintains exclusive control of a segregated non-interest
bearing bank account (the "Property Account") to hold all payments made in
respect of the Convertible Debentures for the benefit of the holders of the
Trust Securities. The Institutional Trustee will make payments of
distributions and payments on liquidation, redemption and otherwise to the
holders of the Trust Securities out of funds from the Property Account. The
Guarantee Trustee holds the Guarantee for the benefit of the holders of the
Convertible Preferred Securities. McKesson, as the holder of all of the Common
Securities, has the right to appoint, remove or replace any MFT Trustee and to
increase or decrease the number of MFT Trustees. McKesson is to pay all fees
and expenses related to McKesson Financing Trust and the Original Offering of
the Trust Securities. See "Description of the Convertible Debentures--
Miscellaneous."
 
  The Common Securities rank pari passu, and payments are made thereon pro
rata, with the Convertible Preferred Securities, except that upon the
occurrence and continuance of an event of default under the Declaration
resulting from an Event of Default under the Indenture, the rights of the
holders of the Common Securities to payment in respect of distributions and
payments upon liquidation, redemption or otherwise will be subordinated to the
rights of holders of the Convertible Preferred Securities. See "Description of
Convertible Preferred Securities--General."
 
  The rights of the holders of the Convertible Preferred Securities, including
economic rights, rights to information and voting rights, are set forth in the
Declaration and the Delaware Business Trust Act (the "Trust Act"). The
Declaration, the Indenture and the Guarantee also incorporate by reference the
terms of the Trust Indenture Act. It is expected that, at the time the Shelf
Registration Statement becomes effective, the Declaration, the Indenture and
the Guarantee will be qualified under the Trust Indenture Act.
 
  The place of business and the telephone number of the Trust are the
principal executive offices and telephone number of the Company. See "The
Company."
 
                                      14
<PAGE>
 
              DESCRIPTION OF THE CONVERTIBLE PREFERRED SECURITIES
 
  The Convertible Preferred Securities were issued pursuant to the terms of
the Declaration. The Declaration incorporates by reference terms of the Trust
Indenture Act. The Declaration will be qualified under the Trust Indenture
Act. The Institutional Trustee acts as indenture trustee for the Convertible
Preferred Securities under the Declaration for purposes of compliance with the
provisions of the Trust Indenture Act. The terms of the Convertible Preferred
Securities include those stated in the Declaration and those made part of the
Declaration by the Trust Indenture Act. The following summary of certain terms
and provisions of the Convertible Preferred Securities does not purport to be
complete and is subject to, and qualified in its entirety by reference to, the
Declaration, the Trust Act and the Trust Indenture Act.
 
GENERAL
 
  The Declaration authorized the Regular Trustees to issue, on behalf of the
Trust, the Trust Securities, which represent undivided beneficial interests in
the assets of the Trust. All of the Common Securities are owned by McKesson.
The Common Securities rank pari passu, and payments are made thereon on a pro
rata basis, with the Convertible Preferred Securities, except that upon the
occurrence and during the continuance of a Declaration Event of Default, the
rights of the holders of the Common Securities to receive payment of periodic
distributions and payments upon liquidation, redemption and otherwise will be
subordinated to the rights of the holders of the Convertible Preferred
Securities. The Declaration does not permit the issuance by the Trust of any
securities other than the Trust Securities or the incurrence of any
indebtedness by the Trust. Pursuant to the Declaration, the Institutional
Trustee holds the Convertible Debentures purchased by the Trust for the
benefit of the holders of the Trust Securities. The payment of distributions
out of money held by the Trust, and payments upon redemption of the
Convertible Preferred Securities or liquidation of the Trust, are guaranteed
by McKesson to the extent described under "Description of the Guarantee." The
Guarantee is held by the Guarantee Trustee for the benefit of the holders of
the Convertible Preferred Securities. The Guarantee does not cover payment of
distributions when the Trust does not have sufficient available funds to pay
such distributions. In such event, the remedy of a holder of Convertible
Preferred Securities is to vote to direct the Institutional Trustee to enforce
the Institutional Trustee's rights under the Convertible Debentures or, in
certain limited circumstances, to take Direct Action. See "--Voting Rights"
and "--Declaration Events of Default."
 
DISTRIBUTIONS
 
  Distributions on the Convertible Preferred Securities are fixed at a rate
per annum (the "distribution rate") of 5% of the stated liquidation amount of
$50 per Convertible Preferred Security. Distributions in arrears for more than
one quarter will accrue interest thereon at the distribution rate (to the
extent permitted by applicable law), compounded quarterly. The term
"distribution" as used herein includes any such interest payable unless
otherwise stated. The amount of distributions payable for any period will be
computed on the basis of a 360-day year of twelve 30-day months. The amount of
distributions payable for any period shorter than a full quarterly period for
which distributions are computed will be computed on the basis of the actual
number of days elapsed per 30-day month.
 
  Distributions on the Convertible Preferred Securities will be cumulative,
will accrue from the first date that any Convertible Preferred Securities are
issued, and will be payable quarterly in arrears on March 1, June 1, September
1 and December 1 of each year, commencing June 1, 1997, when, as and if
available for payment. Distributions will be made by the Institutional
Trustee, except as otherwise described below.
 
  So long as McKesson shall not be in default in the payment of interest on
the Convertible Debentures, McKesson has the right under the Indenture to
defer payments of interest on the Convertible Debentures by extending the
interest payment period from time to time on the Convertible Debentures,
which, if exercised, would defer quarterly distributions on the Convertible
Preferred Securities (though such distributions would continue to accumulate
with interest thereon (to the extent permitted by applicable law) at the
distribution rate, compounded quarterly, since interest would continue to
accrue on the Convertible Debentures) during any such
 
                                      15
<PAGE>
 
Extension Period. Such right to extend the interest payment period for the
Convertible Debentures is limited to a period not exceeding 20 consecutive
quarters and such period may not extend beyond the maturity of the Convertible
Debentures. Each Extension Period, if any, will end on an Interest Payment
Date (as defined herein) for the Convertible Debentures; such date will also
be a distribution payment date for the Convertible Preferred Securities. In
the event that McKesson exercises its right to defer payment of interest,
then, during such Extension Period McKesson shall not (a) declare or pay
dividends on, make distributions with respect to, or redeem, purchase or
acquire, or make a liquidation payment with respect to, any of its capital
stock or (b) make any payment of interest, principal or premium, if any, on or
repay, repurchase or redeem any debt securities issued by McKesson that rank
pari passu with or junior in interest to the Convertible Debentures or make
any guarantee payments with respect to any guarantee by the Company of the
debt securities of any subsidiary of the Company if such guarantee ranks pari
passu with or junior in interest to the Convertible Debentures (other than (i)
as a result of a reclassification of McKesson capital stock or the exchange or
conversion of one class or series of McKesson capital stock for another class
or series of McKesson capital stock, (ii) the purchase of fractional interests
in shares of McKesson capital stock pursuant to the conversion or exchange
provisions of such McKesson capital stock or the security being converted or
exchanged for McKesson capital stock, (iii) dividends or distributions in
Common Stock of the Company, (iv) any declaration of a dividend in connection
with the implementation of a stockholders' rights plan, or the issuance of
stock under any such plan in the future, or the redemption or repurchase of
any such rights pursuant thereto, (v) payments under the Guarantee and Common
Securities Guarantee (as defined herein), (vi) purchases of Common Stock
related to the issuance of Common Stock or rights under any of the Company's
benefit plans for its directors, officers or employees and (vii) obligations
under any dividend reinvestment and stock purchase plans). Prior to the
termination of any such Extension Period, McKesson may further extend the
interest payment period; provided that such Extension Period, together with
all such previous and further extensions, may not exceed 20 consecutive
quarters or extend beyond the maturity of the Convertible Debentures. Upon the
termination of any Extension Period and the payment of all amounts then due,
McKesson may commence a new Extension Period, subject to the above
requirements. Consequently, there could be multiple Extension Periods of
varying length throughout the term of the Convertible Debentures. See
"Description of the Convertible Debentures--Interest" and "--Option to Extend
Interest Payment Period." If distributions are deferred, the deferred
distributions and interest thereon shall be payable on the distribution
payment date on which the relevant Extension Period terminates and shall be
paid to holders of record of the Convertible Preferred Securities as they
appear on the books and records of the Trust at the close of business on the
record date next preceding such distribution payment date.
 
  Distributions on the Convertible Preferred Securities must be paid on the
date payable to the extent that the Trust has funds available for the payment
of such distributions. The Trust's funds available for distribution to the
holders of the Convertible Preferred Securities will be limited to payments
received from McKesson on the Convertible Debentures. See "Description of the
Convertible Debentures." The payment of distributions out of monies held by
the Trust is guaranteed by McKesson to the extent set forth under "Description
of the Guarantee."
 
  Distributions on the Convertible Preferred Securities will be payable to the
holders thereof as they appear on the books and records of the Trust at the
close of business on the relevant record dates, which will be fifteen days
prior to the relevant payment dates. Such distributions will be paid through
the Institutional Trustee who will hold amounts received in respect of the
Convertible Debentures for the benefit of the holders of the Trust Securities.
Subject to any applicable laws and regulations and the provisions of the
Declaration, each such payment will be made as described under "--Form,
Denomination and Registration" below. In the event that any date on which
distributions are to be made on the Convertible Preferred Securities is not a
Business Day (as defined herein), then payment of the distributions payable on
such date will be made on the next succeeding day that is a Business Day (and
without any interest or other payment in respect of any such delay), except
that, if such Business Day is in the next succeeding calendar year, such
payment shall be made on the immediately preceding Business Day, in each case
with the same force and effect as if made on such date. A "Business Day" shall
mean any day other than Saturday, Sunday or any other day on which banking
institutions in The City of New York or Wilmington, Delaware are permitted or
required by any applicable law to close.
 
 
                                      16
<PAGE>
 
CONVERSION RIGHTS
 
  General. The Convertible Preferred Securities are convertible at any time
beginning May 21, 1997 through the close of business on the Business Day prior
to the maturity date of the Convertible Debentures (or, in the case of
Convertible Preferred Securities called for redemption, prior to the close of
business on the Business Day prior to the Redemption Date) (the "Conversion
Expiration Date"), at the option of the holders thereof and in the manner
described below, into shares of McKesson Common Stock at an initial conversion
rate of .6709 shares of McKesson Common Stock for each Convertible Preferred
Security (equivalent to a conversion price (the "Conversion Price") of $74.53
per share of McKesson Common Stock), subject to adjustment as described under
"--Conversion Price Adjustments--General" below.
 
  The terms of the Convertible Preferred Securities provide that a holder of a
Convertible Preferred Security wishing to exercise its conversion right shall
surrender such Convertible Preferred Security, together with an irrevocable
conversion notice, to the Institutional Trustee, as conversion agent (the
"Conversion Agent") which shall, on behalf of such holder, exchange such
Convertible Preferred Security for an equivalent portion of the Convertible
Debentures and immediately convert an equivalent amount of Convertible
Debentures into McKesson Common Stock. Holders may obtain copies of the
required form of the conversion notice from the Conversion Agent. Additional
procedures for converting book-entry Convertible Preferred Securities into
shares of McKesson Common Stock are described below under "--Form,
Denomination and Registration."
 
  Accrued distributions will not be paid on the Convertible Preferred
Securities that are converted, provided, however, that if any Convertible
Preferred Security is converted after the close of business on a record date
for payment of distributions thereon, the distributions payable on the related
payment date with respect to such Convertible Preferred Security shall be paid
on such distribution date to the person who was the registered holder thereof
at the close of business on such record date, despite such conversion, unless
such Convertible Preferred Security has been called for redemption on a
Redemption Date falling between such record date and the corresponding
distribution payment date, in which case the amount of such payment shall
include distributions accrued to, but excluding, such Redemption Date and such
payment shall be made to the converting holder. Except as provided in the
immediately preceding sentence, neither the Trust nor McKesson shall make any
payment, allowance or adjustment for accumulated and unpaid distributions on
converted Convertible Preferred Securities. McKesson will make no payment or
allowance for distributions on the shares of McKesson Common Stock issued upon
such conversion, except to the extent that such shares of McKesson Common
Stock are held of record on the record date for any such distributions.
 
  No fractional shares of McKesson Common Stock will be issued as a result of
conversion, but in lieu thereof such fractional interest will be paid by
McKesson in cash based on the Closing Price (as defined in the Declaration) of
McKesson Common Stock on the date such Convertible Preferred Securities are
surrendered for conversion.
 
  Conversion Price Adjustments--General. The initial conversion price of
$74.53 per share of McKesson Common Stock is subject to adjustment (under
formulae set forth in the Indenture) in certain events, including (i) the
issuance of shares of McKesson Common Stock as a dividend or a distribution
with respect to McKesson Common Stock, (ii) certain subdivisions and
combinations of McKesson Common Stock, (iii) the issuance to all holders of
McKesson Common Stock of certain rights or warrants entitling them to
subscribe for or purchase shares of McKesson Common Stock, (iv) the
distribution to all holders of McKesson Common Stock of shares of capital
stock (other than McKesson Common Stock) or evidences of indebtedness of
McKesson or of assets (including securities, but excluding those rights,
warrants, dividends and distributions referred to above or paid in cash), (v)
distributions consisting of cash, excluding any quarterly cash dividend on
McKesson Common Stock to the extent that the aggregate cash dividend per share
of McKesson Common Stock in any quarter does not exceed the greater of (x) the
amount per share of McKesson Common Stock of the next preceding quarterly
dividend on McKesson Common Stock to the extent that such preceding quarterly
dividend did not require an adjustment of the conversion rate pursuant to this
clause (v) (as adjusted to reflect subdivisions or combinations of McKesson
Common Stock), and (y) 3.75% of the average of the daily Closing Price (as
defined in the
 
                                      17
<PAGE>
 
Indenture) of McKesson Common Stock during the ten consecutive Trading Days
(as defined in the Indenture) immediately prior to the date of declaration of
such dividend, and excluding any dividend or distribution in connection with
the liquidation, dissolution or winding-up of McKesson, (vi) payment to
holders of McKesson Common Stock in respect of a tender or exchange offer by
McKesson or any subsidiary for McKesson Common Stock to the extent that the
cash and value of any other consideration included in such payment per share
of McKesson Common Stock exceeds the Closing Price (as defined in the
Indenture) per share of Common Stock on the Trading Day next succeeding the
last date on which tenders or exchanges may be made pursuant to such tender or
exchange offer, and (vii) payment in respect of a tender offer or exchange
offer by a person other than McKesson or any subsidiary of McKesson in which,
as of the closing date of the offer, the Board of Directors is not
recommending rejection of the offer. If an adjustment is required to be made
as set forth in clause (v) above as a result of a distribution that is a
quarterly dividend, such adjustment would be based upon the amount by which
such distribution exceeds the amount of the quarterly cash dividend permitted
to be excluded pursuant to such clause (v). If an adjustment is required to be
made based upon the full amount of the distribution that is not a quarterly
dividend, such adjustment would be based upon the full amount of the
distribution. The adjustment referred to in clause (vii) above will only be
made (A) if the tender offer or exchange offer is for an amount that increases
that person's ownership of McKesson Common Stock to more than 25% of the total
shares of McKesson Common Stock outstanding and (B) if the cash and value of
any other consideration included in such payment per share of McKesson Common
Stock exceeds the Closing Price per share of McKesson Common Stock on the
Business Day next succeeding the last date on which tenders or exchanges may
be made pursuant to such tender or exchange offer. The adjustment referred to
in clause (vii) above will not be made, however, if, as of the closing of the
offer, the offering documents with respect to such offer disclose a plan or an
intention to cause McKesson to engage in a consolidation or merger of McKesson
or a sale of all or substantially all of McKesson's assets. The Convertible
Debentures provide for corresponding anti-dilution adjustments.
 
  McKesson from time to time may to the extent permitted by law reduce the
conversion price of the Convertible Debentures (and thus the conversion price
of the Convertible Preferred Securities) by any amount for any period of at
least 20 days, in which case McKesson shall give at least 15 days' notice of
such reduction.
 
  No adjustment in the conversion price will be required unless such
adjustment would require a change of at least one percent (1%) in the
conversion price then in effect; provided, however, that any adjustment that
would not be required to be made shall be carried forward and taken into
account in any subsequent adjustment. If any action would require adjustment
of the conversion price pursuant to more than one of the provisions described
above, only one adjustment shall be made and such adjustment shall be the
amount of adjustment that has the highest absolute value to the holder of the
Convertible Preferred Securities. Except as stated above, the conversion price
will not be adjusted for the issuance of McKesson Common Stock or any
securities convertible into or exchangeable for McKesson Common Stock or
carrying the right to purchase any of the foregoing.
 
  Conversion Price Adjustments--Merger, Consolidation or Sale of Assets of
McKesson. If any transaction shall occur (including without limitation (i) any
recapitalization or reclassification of shares of McKesson Common Stock (other
than a change in par value, or from par value to no par value, or from no par
value to par value, or as a result of a subdivision or combination of McKesson
Common Stock), (ii) any consolidation or merger of McKesson with or into
another person or any merger of another person into McKesson (other than a
merger that does not result in a reclassification, conversion, exchange or
cancellation of McKesson Common Stock), (iii) any sale or transfer of all or
substantially all of the assets of McKesson, or (iv) any compulsory share
exchange) pursuant to which either shares of McKesson Common Stock shall be
converted into the right to receive other securities, cash or other property,
or, in the case of a sale or transfer of all or substantially all of the
assets of McKesson, the holders of McKesson Common Stock shall be entitled to
receive other securities, cash or other property, then appropriate provision
shall be made so that the holder of each Convertible Preferred Security then
outstanding shall have the right thereafter to convert such Convertible
Preferred Security only into:
 
    (x) in the case of any such transaction that does not constitute a Common
  Stock Fundamental Change (as defined below) and subject to funds being
  legally available for such purpose under applicable law at the time of such
  conversion, the kind and amount of the securities, cash or other property
  that would have been
 
                                      18
<PAGE>
 
  receivable upon such recapitalization, reclassification, consolidation,
  merger, sale, transfer or share exchange by a holder of the number of
  shares of McKesson Common Stock issuable upon conversion of such
  Convertible Preferred Security immediately prior to such recapitalization,
  reclassification, consolidation, merger, sale, transfer or share exchange,
  after giving effect, in the case of any Non-Stock Fundamental Change (as
  defined below), to any adjustment in the conversion price in accordance
  with clause (i) of the second following paragraph, and
 
    (y) in the case of any such transaction that constitutes a Common Stock
  Fundamental Change, common stock of the kind received by holders of
  McKesson Common Stock as a result of such Common Stock Fundamental Change
  in an amount determined in accordance with clause (ii) of the second
  following paragraph.
 
  The company formed by such consolidation or resulting from such merger or
that acquires assets or that acquires McKesson's shares, as the case may be,
shall make provisions in its certificate or articles of incorporation or other
constituent document to establish such right. Such certificate or articles of
incorporation or other constituent document shall provide for adjustments
that, for events subsequent to the effective date of such certificate or
articles of incorporation or other constituent documents, shall be as nearly
equivalent as may be practicable to the relevant adjustments provided for in
the preceding paragraphs and in this paragraph.
 
  Notwithstanding any other provision in the preceding paragraphs to the
contrary, if any Fundamental Change (as defined below) occurs, then the
conversion price in effect will be adjusted immediately after such Fundamental
Change as follows:
 
    (i) in the case of a Non-Stock Fundamental Change, the conversion price
  of the Convertible Preferred Securities immediately following such Non-
  Stock Fundamental Change shall be the lower of (A) the conversion price in
  effect immediately prior to such Non-Stock Fundamental Change, but after
  giving effect to any other prior adjustments effected pursuant to the
  preceding paragraphs, and (B) the product of (1) the greater of the
  Applicable Price (as defined below) and the then applicable Reference
  Market Price (as defined below) and (2) a fraction, the numerator of which
  is $50 and the denominator of which is (x) the amount of the redemption
  price for one Convertible Preferred Security if the redemption date were
  the date of such Non-Stock Fundamental Change (or, for the twelve-month
  periods commencing March 4, 1997, March 4, 1998 and March 4, 1999, the
  product of 105.0%, 104.5% and 104.0%, respectively, times $50) plus (y) any
  then-accrued and unpaid distributions on one Convertible Preferred
  Security; and
 
    (ii) in the case of a Common Stock Fundamental Change, the conversion
  price of Convertible Preferred Securities immediately following such Common
  Stock Fundamental Change shall be the conversion price in effect
  immediately prior to such Common Stock Fundamental Change, but after giving
  effect to any other prior adjustments effected pursuant to the preceding
  paragraphs, multiplied by a fraction, the numerator of which is the
  Purchaser Stock Price (as defined below) and the denominator of which is
  the Applicable Price; provided, however, that in the event of a Common
  Stock Fundamental Change in which (A) 100% of the value of the
  consideration received by a holder of McKesson Common Stock is common stock
  of the successor, acquiror or other third party (and cash, if any, paid
  with respect to any fractional interests in such common stock resulting
  from such Common Stock Fundamental Change) and (B) all of the McKesson
  Common Stock shall have been exchanged for, converted into or acquired for,
  common stock of the successor, acquiror or other third party (and any cash
  with respect to fractional interests), the conversion price of the
  Convertible Preferred Securities immediately following such Common Stock
  Fundamental Change shall be the conversion price in effect immediately
  prior to such Common Stock Fundamental Change multiplied by a fraction, the
  numerator of which is one (1) and the denominator of which is the number of
  shares of common stock of the successor, acquiror or other third party
  received by a holder of one share of McKesson Common Stock as a result of
  such Common Stock Fundamental Change.
 
  Depending upon whether a Fundamental Change is a Non-Stock Fundamental
Change or a Common Stock Fundamental Change, a holder may receive
significantly different consideration upon conversion. In the event of a Non-
Stock Fundamental Change, the holder has the right to convert Convertible
Preferred Securities into the
 
                                      19
<PAGE>
 
kind and amount of the shares of stock and other securities or property or
assets (including cash), except as otherwise provided above, as is determined
by the number of shares of McKesson Common Stock receivable upon conversion at
the conversion price as adjusted in accordance with clause (i) of the
preceding paragraph. However, in the event of a Common Stock Fundamental
Change in which less than 100% of the value of the consideration received by a
holder of McKesson Common Stock is common stock of the successor, acquiror or
other third party, a holder of a Convertible Preferred Security who converts
such share following the Common Stock Fundamental Change will receive
consideration in the form of such common stock only, whereas a holder who
converted such share prior to the Common Stock Fundamental Change would have
received consideration in the form of such common stock as well as any other
securities or assets (which may include cash) issuable upon conversion of such
Convertible Preferred Security immediately prior to such Common Stock
Fundamental Change.
 
  The term "Applicable Price" means (i) in the event of a Non-Stock
Fundamental Change in which the holders of McKesson Common Stock receive only
cash, the amount of cash received by a holder of one share of McKesson Common
Stock and (ii) in the event of any other Fundamental Change, the average of
the daily Closing Price (as defined in the Indenture) for one share of
McKesson Common Stock during the 10 Trading Days immediately prior to the
record date for the determination of the holders of McKesson Common Stock
entitled to receive cash, securities, property or other assets in connection
with such Fundamental Change or, if there is no such record date, prior to the
date upon which the holders of McKesson Common Stock shall have the right to
receive such cash, securities, property or other assets.
 
  The term "Common Stock Fundamental Change" means any Fundamental Change in
which more than 50% of the value (as determined in good faith by the Board of
Directors of McKesson) of the consideration received by holders of McKesson
Common Stock consists of common stock that, for the 10 Trading Days
immediately prior to such Fundamental Change, has been admitted for listing or
admitted for listing subject to notice of issuance on a national securities
exchange or quoted on The Nasdaq National Market; provided, however, that a
Fundamental Change shall not be a Common Stock Fundamental Change unless
either (i) McKesson continues to exist after the occurrence of such
Fundamental Change and the outstanding Convertible Preferred Securities
continue to exist as outstanding Convertible Preferred Securities, or (ii) not
later than the occurrence of such Fundamental Change, the outstanding
Convertible Preferred Securities are converted into or exchanged for shares of
convertible preferred stock or debentures of a corporation succeeding to the
business of McKesson, which convertible preferred stock has powers,
preferences and relative, participating, optional or other rights, and
qualifications, limitations and restrictions substantially similar to those of
the Convertible Preferred Securities and which debentures have terms
substantially similar to those of the Convertible Debentures.
 
  The term "Fundamental Change" means the occurrence of any transaction or
event or series of transactions or events pursuant to which all or
substantially all of the McKesson Common Stock shall be exchanged for,
converted into, acquired for or shall constitute solely the right to receive
cash, securities, property or other assets (whether by means of an exchange
offer, liquidation, tender offer, consolidation, merger, combination,
reclassification, recapitalization or otherwise); provided, however, in the
case of any such series of transactions or events, for purposes of adjustment
of the conversion price, such Fundamental Change shall be deemed to have
occurred when substantially all of the McKesson Common Stock shall have been
exchanged for, converted into or acquired for, or shall constitute solely the
right to receive, such cash, securities, property or other assets, but the
adjustment shall be based upon the consideration that the holders of McKesson
Common Stock received in the transaction or event as a result of which more
than 50% of the McKesson Common Stock shall have been exchanged for, converted
into or acquired for, or shall constitute solely the right to receive, such
cash, securities, property or other assets.
 
  The term "Non-Stock Fundamental Change" means any Fundamental Change other
than a Common Stock Fundamental Change.
 
                                      20
<PAGE>
 
  The term "Purchaser Stock Price" means, with respect to any Common Stock
Fundamental Change, the average of the daily Closing Price for one share of
the common stock received by holders of McKesson Common Stock (determined as
provided in the Declaration) in such Common Stock Fundamental Change during
the 10 Trading Days immediately prior to the date fixed for the determination
of the holders of McKesson Common Stock entitled to receive such common stock
or, if there is no such date, prior to the date upon which the holders of
McKesson Common Stock shall have the right to receive such common stock.
 
  The Term "Reference Market Price" shall initially mean $39.75 (which is an
amount equal to 66 2/3% of the reported last sale price for McKesson Common
Stock on the New York Stock Exchange on February 13, 1997 (the date of the
pricing of the Original Offering)) and, in the event of any adjustment to the
conversion price other than as a result of a Fundamental Change, the Reference
Market Price shall also be adjusted so that the ratio of the Reference Market
Price to the conversion price after giving effect to any such adjustment shall
also be the same as the ratio of the initial Reference Market Price to the
initial conversion price of $74.53 per share.
 
MANDATORY REDEMPTION
 
  The Convertible Preferred Securities will be redeemed upon repayment of the
Convertible Debentures at their maturity or to the extent that the Convertible
Debentures are redeemed or repaid upon acceleration. The Convertible
Debentures will mature on June 1, 2027, and may be redeemed, in whole or in
part, at any time on or after March 4, 2000, or at any time in certain
circumstances upon the occurrence of a Tax Event. Upon the repayment of the
Convertible Debentures, whether at maturity, upon redemption or otherwise, the
proceeds from such repayment shall simultaneously be applied to redeem Trust
Securities having an aggregate liquidation amount equal to the aggregate
principal amount of the Convertible Debentures so repaid or redeemed at the
appropriate Redemption Price (expressed as percentages of the liquidation
amount of the Convertible Preferred Securities) set forth below, together with
accrued and unpaid distributions (including, if distributions shall have been
deferred as the result of an Extension Period, interest thereon to the extent
permitted by applicable law) to, but excluding, the redemption date, if
redeemed during the 12-month period beginning March 4 of the applicable year
set forth below; provided, that holders of Trust Securities shall be given not
less than 30 nor more than 60 days notice of such redemption. See "Description
of the Convertible Debentures--Redemption at the Option of McKesson." In the
event that fewer than all of the outstanding Convertible Preferred Securities
are to be redeemed, the Convertible Preferred Securities will be redeemed pro
rata as described under "--Form, Denomination and Registration" below.
 
<TABLE>
<CAPTION>
            YEAR                         REDEMPTION PRICE
            ----                         ----------------
            <S>                          <C>
            2000........................      103.5%
            2001........................      103.0
            2002........................      102.5
            2003........................      102.0
            2004........................      101.5
            2005........................      101.0
            2006........................      100.5
</TABLE>
 
and 100.0% if redeemed on or after March 4, 2007. If Convertible Preferred
Securities are redeemed on any distribution payment date, accumulated and
unpaid distributions shall be payable to holders of record on the relevant
record date.
 
SPECIAL EVENT DISTRIBUTION; TAX EVENT REDEMPTION
 
  "Tax Event" means that the Regular Trustees shall have received an opinion
of nationally recognized independent tax counsel experienced in such matters
(a "Dissolution Tax Opinion") to the effect that as a result of (a) any
amendment to, clarification of, or change (including any announced prospective
change) in the laws,
 
                                      21
<PAGE>
 
or any regulations thereunder, of the United States or any political
subdivision or taxing authority thereof or therein, (b) any judicial decision,
official administrative pronouncement, ruling, regulatory procedure, notice or
announcement, including any notice or announcement of intent to adopt such
procedures or regulations (an "Administrative Action"), or (c) any amendment
to, clarification of, or change in the official position or the interpretation
of such Administrative Action or judicial decision that differs from the
theretofore generally accepted position, in each case, by any legislative
body, court, governmental authority or regulatory body, irrespective of the
manner in which such amendment, clarification or change is made known, which
amendment, clarification, or change is effective or such pronouncement or
decision is announced, in each case, on or after February 13, 1997, there is
the creation by such amendment, clarification, change or Administrative Action
of more than an insubstantial risk that (i) the Trust is or will be subject to
United States federal income tax with respect to interest accrued or received
on the Convertible Debentures, (ii) the Trust is or will be subject to more
than a de minimis amount of taxes (other than withholding taxes), duties or
other governmental charges, or (iii) interest paid in cash by McKesson to the
Trust on the Convertible Debentures is not, or will not be, deductible, in
whole or in part, by McKesson for United States federal income tax purposes.
Notwithstanding the foregoing, a Tax Event shall not include any change in tax
law that requires McKesson for United States federal income tax purposes to
defer taking a deduction for any OID that accrues with respect to the
Convertible Debentures until the interest payment related to such OID is paid
by the Company in cash; provided, that such change in tax law does not create
more than an insubstantial risk that McKesson will be prevented from taking a
deduction for OID accruing with respect to the Convertible Debentures at a
date that is no later than the date the interest payment related to such OID
is actually paid by McKesson in cash.
 
  "Investment Company Event" means that the Regular Trustees shall have
received an opinion of nationally recognized independent counsel experienced
in such matters to the effect that, as a result of the occurrence of a change
in law or regulation or a written change in interpretation or application of
law or regulation by any legislative body, court, governmental agency or
regulatory authority on or after February 13, 1997, there is more than an
insubstantial risk that the Trust is or will be considered an "investment
company" that is required to be registered under the Investment Company Act of
1940, as amended (the "1940 Act").
 
  If, at any time, a Tax Event or an Investment Company Event (each, a
"Special Event") shall occur and be continuing, the Trust may with the consent
of McKesson, except in the limited circumstances described below, be dissolved
with the result that Convertible Debentures with an aggregate principal amount
equal to the aggregate stated liquidation amount of, with an interest rate
identical to the distribution rate of, and accrued and unpaid interest equal
to accrued and unpaid distributions on, the Trust Securities, would be
distributed to the holders of the Trust Securities in liquidation of such
holders' interest in the Trust on a pro rata basis within 90 days following
the occurrence of the Special Event; provided, that such dissolution and
distribution shall be conditioned on (i) the Regular Trustees' receipt of an
opinion of independent tax counsel experienced in such matters (a "No
Recognition Opinion"), which opinion may rely on published revenue rulings of
the Internal Revenue Service, to the effect that the holders of the Trust
Securities will not recognize any income, gain or loss for United States
federal income tax purposes as a result of such dissolution and distribution
of Convertible Debentures, (ii) McKesson or the Trust being unable to avoid
such Special Event within such 90-day period by taking some ministerial action
or pursuing some other reasonable measure that will have no adverse effect on
the Trust, McKesson or the holders of the Trust Securities and (iii)
McKesson's prior written consent to such dissolution and distribution. If
McKesson declines to consent to such dissolution and distribution, McKesson
may incur an obligation to pay Additional Sums. See "Description of the
Convertible Debentures--Additional Sums." Furthermore, if after receipt of a
Dissolution Tax Opinion by the Regular Trustees (i) McKesson has received an
opinion (a "Redemption Tax Opinion") of nationally recognized independent tax
counsel experienced in such matters that, as a result of a Tax Event, there is
more than an insubstantial risk that McKesson would be precluded from
deducting the interest on the Convertible Debentures for United States federal
income tax purposes even after the Convertible Debentures were distributed to
the holders of Trust Securities in liquidation of such holders' interests in
the Trust as described above, or (ii) the Regular Trustees shall have been
informed by such tax counsel that it cannot deliver a No Recognition Opinion
to the Trust,
 
                                      22
<PAGE>
 
McKesson shall have the right, upon not less than 30 nor more than 60 days
notice, to redeem the Convertible Debentures, in whole or in part, at 100% of
the principal amount thereof plus accrued and unpaid interest thereon for cash
within 90 days following the occurrence of such Tax Event. Following such
redemption, Trust Securities with an aggregate liquidation amount equal to the
aggregate principal amount of the Convertible Debentures so redeemed shall be
redeemed by the Trust at the liquidation amount thereof plus accrued and
unpaid distributions thereon to the redemption date on a pro rata basis;
provided, however, that if at the time there is available to McKesson or the
Trust the opportunity to eliminate, within such 90 day period, the Tax Event
by taking some ministerial action, such as filing a form or making an election
or pursuing some other similar reasonable measure that will have no adverse
effect on the Trust, McKesson or the holders of Trust Securities, McKesson or
the Trust will pursue such measure in lieu of redemption.
 
  After the date for any distribution of Convertible Debentures upon
dissolution of the Trust, (i) the Trust Securities will no longer be deemed to
be outstanding and (ii) certificates representing Trust Securities will be
deemed to represent Convertible Debentures having an aggregate principal
amount equal to the aggregate stated liquidation amount of, with an interest
rate identical to the distribution rate of, and accrued and unpaid interest
(including Compound Interest (as defined herein)) equal to accrued and unpaid
distributions on, such Trust Securities until such certificates are presented
to McKesson or its agent for transfer or reissuance.
 
REDEMPTION PROCEDURES FOR REDEMPTION BY THE TRUST
 
  The Trust may not redeem fewer than all of the outstanding Convertible
Preferred Securities unless all accrued and unpaid distributions have been
paid on all Convertible Preferred Securities for all quarterly distribution
periods terminating on or prior to the date of redemption.
 
  The Trust shall not be required to (i) in the event of any redemption in
part, issue, register the transfer of or exchange any Convertible Preferred
Securities during a period beginning at the opening of business 15 days before
any selection for redemption of Convertible Preferred Securities and ending at
the close of business on the earliest date in which the relevant notice of
redemption is deemed to have been given to all holders of Convertible
Preferred Securities to be so redeemed or (ii) register the transfer of or
exchange any Convertible Preferred Securities selected for redemption, in
whole or in part, except for the unredeemed portion of any Convertible
Preferred Securities being redeemed in part.
 
  If the Trust gives a notice of redemption in respect of Convertible
Preferred Securities (which notice will be irrevocable), then, by 12:00 noon,
New York City time, on the redemption date, provided that McKesson has paid to
the Institutional Trustee a sufficient amount of cash in connection with the
related redemption of the Convertible Debentures, the Trust will irrevocably
deposit with the depositary for the Global Securities (the "Depository") funds
sufficient to pay the amount payable on redemption of all book-entry
certificates and will give the Depository irrevocable instructions and
authority to pay such amount in respect of the Global Securities and will
irrevocably deposit with the paying agent for the Convertible Preferred
Securities funds sufficient to pay such amount in respect of any certificated
Convertible Preferred Securities and will give such paying agent irrevocable
instructions and authority to pay such amount to the holders of certificated
Convertible Preferred Securities upon surrender of their certificates. If
notice of redemption shall have been given and funds deposited as required,
then, from and after the redemption date, distributions will cease to accrue
and all rights of holders of such Convertible Preferred Securities so called
for redemption will cease, except the right of the holders of such Convertible
Preferred Securities to receive the Redemption Price plus accrued and unpaid
distributions on the Convertible Preferred Securities to be redeemed, but
without interest on such Redemption Price. In the event that any date fixed
for redemption of Convertible Preferred Securities is not a Business Day, then
payment of the Redemption Price payable on such date will be made on the next
succeeding day that is a Business Day (without any interest or other payment
in respect of any such delay) except that, if such Business Day falls in the
next calendar year, such payment will be made on the immediately preceding
Business Day. In the event that payment of the Redemption Price in respect of
Convertible Preferred Securities is improperly withheld or refused and not
paid either by the Trust or by McKesson pursuant to the Guarantee,
distributions on such Convertible Preferred
 
                                      23
<PAGE>
 
Securities will continue to accrue at the then applicable rate from the
original redemption date to the date of payment, in which case the actual
payment date will be considered the date fixed for redemption for purposes of
calculating the Redemption Price.
 
  In the event that fewer than all of the outstanding Convertible Preferred
Securities are to be redeemed, the Convertible Preferred Securities will be
redeemed pro rata.
 
  Subject to the foregoing and applicable law (including without limitation,
United States federal securities laws), McKesson or its subsidiaries may at
any time, and from time to time, purchase outstanding Convertible Preferred
Securities by tender, in the open market or by private agreement.
 
SUBORDINATION OF COMMON SECURITIES
 
  Payment of distributions on, and the amount payable upon redemption of, the
Trust Securities, as applicable, shall be made pro rata based on the
liquidation amount of the Trust Securities; provided however, that, if on any
distribution date or Redemption Date a Declaration Event of Default shall have
occurred and be continuing, no payment of any distribution on, or amount
payable upon redemption of, any Common Security and no other payment on
account of the redemption, liquidation or other acquisition of any Common
Security shall be made unless payment in full in cash of all accumulated and
unpaid distributions on all outstanding Convertible Preferred Securities for
all distribution periods terminating on or prior thereto, or in the case of
payment of the amount payable upon redemption of the Convertible Preferred
Securities, the full Redemption Price, together with accumulated and unpaid
distributions, in respect of all outstanding Convertible Preferred Securities
called for redemption shall have been made or provided for, and all funds
available to the Institutional Trustee shall first be applied to the payment
in full in cash of all distributions on, or the amount payable upon redemption
of, Convertible Preferred Securities then due and payable.
 
  In the case of any Declaration Event of Default, the holder of Common
Securities will be deemed to have waived any such Declaration Event of Default
until all Declaration Events of Default with respect to the Convertible
Preferred Securities have been cured, waived or otherwise eliminated. Until
any such Declaration Events of Default with respect to the Convertible
Preferred Securities have been so cured, waived or otherwise eliminated, the
Institutional Trustee shall act solely on behalf of the holders of the
Convertible Preferred Securities and not the holder of the Common Securities,
and only the holders of the Convertible Preferred Securities will have the
right to direct the Institutional Trustee to act in accordance with the terms
of the Convertible Preferred Securities and the Common Securities.
 
LIQUIDATION OF TRUST AND DISTRIBUTION OF CONVERTIBLE DEBENTURES TO HOLDERS
 
  McKesson has the right at any time to cause the Trust to be dissolved with
the result that, after satisfaction of creditors of the Trust, Convertible
Debentures with an aggregate principal amount equal to the aggregate stated
liquidation amount of the Convertible Preferred Securities and the Common
Securities would be distributed on a pro rata basis to the holders of the
Convertible Preferred Securities and the Common Securities in liquidation of
such holders' interests in the Trust within 90 days following notice given to
the holders of the Convertible Preferred Securities, subject to the Regular
Trustees' having received an opinion of nationally recognized independent
counsel experienced in such matters to the effect that the holders will not
recognize any income, gain or loss for United States federal income tax
purposes as a result of the dissolution of the Trust and such distribution to
holders of Convertible Preferred Securities.
 
LIQUIDATION DISTRIBUTION UPON DISSOLUTION
 
  In the event of any voluntary or involuntary liquidation, dissolution,
winding-up or termination of the Trust (each a "Liquidation"), the then
holders of the Convertible Preferred Securities will be entitled to receive
out of the assets of the Trust, after satisfaction of liabilities to
creditors, distributions in an amount equal to the aggregate of the stated
liquidation amount of $50 per Convertible Preferred Security plus accrued and
unpaid
 
                                      24
<PAGE>
 
distributions thereon (including, if distributions have been deferred as the
result of an Extension Period, interest thereon to the extent permitted by
applicable law) to the date of payment (the "Liquidation Distribution"),
unless, in connection with such Liquidation, Convertible Debentures in an
aggregate stated principal amount equal to the aggregate stated liquidation
amount of, with an interest rate identical to the distribution rate of, and
accrued and unpaid interest equal to accrued and unpaid distributions on, the
Convertible Preferred Securities have been distributed on a pro rata basis to
the holders of the Convertible Preferred Securities.
 
  If, upon any such Liquidation, the Liquidation Distribution can be paid only
in part because the Trust has insufficient assets available to pay in full the
aggregate Liquidation Distribution, then the amounts payable directly by the
Trust on the Convertible Preferred Securities shall be paid on a pro rata
basis. The holders of the Common Securities will be entitled to receive
distributions upon any such dissolution pro rata with the holders of the
Convertible Preferred Securities, except that if a Declaration Event of
Default has occurred and is continuing, the Convertible Preferred Securities
shall have a preference over the Common Securities with regard to such
distributions.
 
  Pursuant to the Declaration, the Trust shall terminate (i) on June 1, 2032,
the expiration of the term of the Trust, (ii) upon the bankruptcy of McKesson
or the holder of the Common Securities, (iii) upon the filing of a certificate
of dissolution or its equivalent with respect to the holder of the Common
Securities or McKesson, the filing of a certificate of cancellation with
respect to the Trust after obtaining the consent of the holders of at least a
majority in liquidation amount of the Trust Securities voting together as a
single class to file such certificate of cancellation, or the revocation of
the charter of the holder of the Common Securities or McKesson and the
expiration of 90 days after the date of revocation without a reinstatement
thereof, (iv) upon the distribution of Convertible Debentures upon the
occurrence of a Special Event, (v) upon the entry of a decree of a judicial
dissolution of the holder of the Common Securities, McKesson or the Trust,
(vi) upon the redemption of all the Trust Securities or (vii) upon the
distribution of McKesson Common Stock to all holders of Convertible Preferred
Securities upon conversion of all outstanding Convertible Preferred
Securities.
 
  There can be no assurance as to the market price for the Convertible
Debentures which may be distributed in exchange for Trust Securities if a
dissolution and liquidation of the Trust were to occur. Accordingly, the
Convertible Debentures that the investor may subsequently receive on
dissolution and liquidation of the Trust may trade at a discount to the price
of the Trust Securities exchanged.
 
DECLARATION EVENTS OF DEFAULT
 
  An event of default under the Indenture (an "Indenture Event of Default")
constitutes an event of default under the Declaration with respect to the
Trust Securities (a "Declaration Event of Default"), provided, that pursuant
to the Declaration, the holder of the Common Securities will be deemed to have
waived any Declaration Event of Default with respect to the Common Securities
until all Declaration Events of Default with respect to the Convertible
Preferred Securities have been cured, waived or otherwise eliminated. Until
such Declaration Events of Default with respect to the Convertible Preferred
Securities have been so cured, waived or otherwise eliminated, the
Institutional Trustee will be deemed to be acting solely on behalf of the
holders of the Convertible Preferred Securities and only the holders of the
Convertible Preferred Securities will have the right to direct the
Institutional Trustee with respect to certain matters under the Declaration,
and therefore the Indenture.
 
  If the Institutional Trustee fails to enforce its rights under the
Convertible Debentures, any holder of Convertible Preferred Securities may
institute a legal proceeding against any person to enforce the Institutional
Trustee's rights under the Convertible Debentures. Notwithstanding the
foregoing, if a Declaration Event of Default has occurred and is continuing
and such event is attributable to the failure of McKesson to pay interest or
principal on the Convertible Debentures on the date such interest or principal
is otherwise payable (or in the case of redemption, the Redemption Date), then
a holder of Convertible Preferred Securities may institute a Direct Action for
payment on or after the respective due dates specified in the Convertible
Debentures. In connection with such Direct Action, McKesson will be subrogated
to the rights of such holders of Convertible
 
                                      25
<PAGE>
 
Preferred Securities under the Declaration to the extent of any payment made
by McKesson to such holder of Convertible Preferred Securities in such Direct
Action. The holders of Convertible Preferred Securities will not be able to
exercise directly any other remedy available to the holders of the Convertible
Debentures.
 
  Upon the occurrence of a Declaration Event of Default, the Institutional
Trustee as the sole holder of the Convertible Debentures will have the right
under the Indenture to declare the principal of and accrued and unpaid
interest on the Convertible Debentures to be immediately due and payable.
McKesson and the Trust are each required to file annually with the
Institutional Trustee an officer's certificate as to its compliance with all
conditions and covenants under the Declaration.
 
VOTING RIGHTS
 
  Except as described herein, under the Trust Act and under the Trust
Indenture Act, and as otherwise required by law and the Declaration, the
holders of the Convertible Preferred Securities have no voting rights.
 
  Subject to the requirement of the Institutional Trustee obtaining a tax
opinion in certain circumstances set forth in the last sentence of the next
paragraph, the holders of a majority in aggregate liquidation amount of the
Convertible Preferred Securities then outstanding have the right to direct the
time, method and place of conducting any proceeding for any remedy available
to the Institutional Trustee, or direct the exercise of any trust or power
conferred upon the Institutional Trustee under the Declaration, including the
right to direct the Institutional Trustee, as holder of the Convertible
Debentures, to (i) exercise the remedies available under the Indenture with
respect to the Convertible Debentures, (ii) waive any past Indenture Event of
Default that is waivable under the Indenture, or (iii) exercise any right to
rescind or annul a declaration that the principal of all the Convertible
Debentures shall be due and payable; provided, however, that if an Indenture
Event of Default has occurred and is continuing then, the holders of 25% of
the aggregate liquidation amount of the Convertible Preferred Securities then
outstanding may direct the Institutional Trustee to declare the principal of
and interest on the Convertible Debentures immediately due and payable;
provided, further, that, where a consent or action under the Indenture would
require the consent or action of holders of more than a majority in principal
amount of the Convertible Debentures then outstanding (a "Super-Majority")
affected thereby, only the holders of at least such Super-Majority in
aggregate liquidation amount of the Convertible Preferred Securities then
outstanding may direct the Institutional Trustee to give such consent or take
such action.
 
  The Institutional Trustee shall notify all holders of the Convertible
Preferred Securities of any notice of default received from the Debt Trustee
with respect to the Convertible Debentures. Such notice shall state that such
Indenture Event of Default also constitutes a Declaration Event of Default.
Except with respect to directing the time, method and place of conducting a
proceeding for a remedy, the Institutional Trustee shall not take any of the
actions described in clauses (i), (ii) or (iii) above unless the Institutional
Trustee has obtained an opinion of nationally recognized independent tax
counsel experienced in such matters to the effect that, as a result of such
action, the Trust will not be classified as other than a grantor trust for
United States federal income tax purposes.
 
  In the event the consent of the Institutional Trustee, as the holder of the
Convertible Debentures, is required under the Indenture with respect to any
amendment, modification or termination of the Indenture or the Convertible
Debentures, the Institutional Trustee shall request the direction of the
holders of the Trust Securities with respect to such amendment, modification
or termination and shall vote with respect to such amendment, modification or
termination as directed by a majority in liquidation amount of the Trust
Securities then outstanding, voting together as a single class; provided,
however, that where a consent under the Indenture would require the consent of
a Super-Majority, the Institutional Trustee may only give such consent at the
direction of the holders of at least the proportion in liquidation amount of
the Trust Securities then outstanding which the relevant Super-Majority
represents of the aggregate principal amount of the Convertible Debentures
then outstanding. The Institutional Trustee shall be under no obligation to
take any such action in accordance with the directions of the holders of the
Trust Securities unless the Institutional Trustee has obtained an opinion of
nationally recognized independent tax counsel experienced in such matters to
the effect that for the purposes of United States federal income tax the Trust
will not be classified as other than a grantor trust.
 
                                      26
<PAGE>
 
  A waiver of an Indenture Event of Default will constitute a waiver of the
corresponding Declaration Event of Default.
 
  Any required approval or direction of holders of Convertible Preferred
Securities may be given at a separate meeting of holders of Convertible
Preferred Securities convened for such purpose, at a meeting of all of the
holders of Trust Securities or pursuant to written consent. The Regular
Trustees will cause a notice of any meeting at which holders of Convertible
Preferred Securities are entitled to vote, or of any matter upon which action
by written consent of such holders is to be taken, to be mailed to each holder
of record of Convertible Preferred Securities. Each such notice will include a
statement setting forth the following information: (i) the date of such
meeting or the date by which such action is to be taken; (ii) a description of
any resolution proposed for adoption at such meeting on which such holders are
entitled to vote or of such matter upon which written consent is sought; and
(iii) instructions for the delivery of proxies or consents. No vote or consent
of the holders of Convertible Preferred Securities is required for the Trust
to redeem and cancel Convertible Preferred Securities or distribute
Convertible Debentures in accordance with the Declaration.
 
  Notwithstanding that holders of Convertible Preferred Securities are
entitled to vote or consent under any of the circumstances described above,
any of the Convertible Preferred Securities that are owned at such time by
McKesson or any entity directly or indirectly controlling or controlled by, or
under direct or indirect common control with, McKesson, shall not be entitled
to vote or consent and shall, for purposes of such vote or consent, be treated
as if such Convertible Preferred Securities were not outstanding.
 
  The procedures by which holders of Convertible Preferred Securities may
exercise their voting rights are described below. See "--Form, Denomination
and Registration."
 
  Holders of the Convertible Preferred Securities have no rights to appoint or
remove the Regular Trustees, who may be appointed, removed or replaced solely
by McKesson as the indirect or direct holder of all of the Common Securities.
 
MODIFICATION OF THE DECLARATION
 
  The Declaration may be amended from time to time by the holders of a
majority of the Common Securities and the Institutional Trustee, without the
consent of the holders of the Convertible Preferred Securities (i) to cure any
ambiguity, correct or supplement any provisions in the Declaration that may be
inconsistent with any other provision, or to make any other provisions with
respect to matters or questions arising under the Declaration, which shall not
be inconsistent with the other provisions of the Declaration, or (ii) to
modify, eliminate or add to any provisions of the Declaration to such extent
as shall be necessary to ensure that the Trust will be classified for United
States federal income tax purposes as a grantor trust at all times that any
Trust Securities are outstanding or to ensure that the Trust will not be
required to register as an investment company under the 1940 Act; provided,
however, such action shall not adversely affect in any material respect the
interests of any holder of Trust Securities, and any amendments of the
Declaration shall become effective when notice thereof is given to the holders
of Trust Securities. The Declaration may be amended by the holders of a
majority of the Common Securities and the Institutional Trustee with (i) the
consent of holders representing not less than a majority (based upon
liquidation amounts) of the outstanding Convertible Preferred Securities and
(ii) receipt by the Regular Trustees of an opinion of nationally recognized
independent counsel experienced in such matters to the effect that such
amendment or the exercise of any power granted to the Regular Trustees in
accordance with such amendment will not affect the Trust's status as a grantor
trust for United States federal income tax purposes or the Trust's exemption
from status as an "investment company" under the 1940 Act, provided that
without the consent of each holder of Trust Securities, the Declaration may
not be amended to (i) change the amount or timing of any distribution on the
Trust Securities or otherwise adversely affect the amount of any distribution
required to be made in respect of the Trust Securities as of a specified date
or (ii) restrict the right of a holder of Trust Securities to institute suit
for the enforcement of any such payment on or after such date.
 
                                      27
<PAGE>
 
  No vote or consent of the holders of Convertible Preferred Securities will
be required to redeem and cancel Convertible Preferred Securities in
accordance with the Declaration.
 
PROPOSED TAX LEGISLATION
 
  On February 6, 1997, as part of President Clinton's Fiscal 1998 Budget
Proposal, the United States Treasury Department proposed legislation that
would, among other things, deny an issuer a deduction for United States
federal income tax purposes for the payment of interest on instruments with
characteristics similar to the Convertible Debentures. If the proposed
legislation were enacted in its current form, it is not expected to apply to
the Convertible Debentures since the proposed effective date for this
provision is the date of first Congressional committee action. There can be no
assurances, however, that the proposed legislation, if enacted, or similar
legislation enacted after the date hereof, would not adversely affect the tax
treatment of the Convertible Debentures, resulting in a Tax Event which would
allow the Company to redeem the Convertible Preferred Securities. See
"Description of the Convertible Preferred Securities--Special Event
Distribution; Tax Redemption."
 
MERGERS, CONSOLIDATIONS OR AMALGAMATION
 
  The Trust may not consolidate, amalgamate, merge with or into, or be
replaced by, or convey, transfer or lease its properties and assets as an
entirety or substantially as an entirety to, any corporation or other entity,
except as described below. The Trust may, with the consent of the Regular
Trustees or, if there are more than two Regular Trustees, a majority of the
Regular Trustees and without the consent of the holders of the Trust
Securities, the Institutional Trustee or the Delaware Trustee, consolidate,
amalgamate, merge with or into, or be replaced by a trust organized as such
under the laws of any state of the United States: provided, that (i) if the
Trust is not the survivor, such successor entity either (x) expressly assumes
all of the obligations of the Trust under the Trust Securities or (y)
substitutes for the Convertible Preferred Securities other securities having
substantially the same terms as the Convertible Preferred Securities (the
"Successor Securities"), so long as the Successor Securities rank the same as
the Convertible Preferred Securities with respect to distributions and
payments upon liquidation, redemption and otherwise, (ii) McKesson expressly
acknowledges a trustee of such successor entity possessing the same powers and
duties as the Institutional Trustee as the holder of the Convertible
Debentures, (iii) such merger, consolidation, amalgamation or replacement does
not cause the Convertible Preferred Securities (including any Successor
Securities) to be downgraded by any nationally recognized statistical rating
organization, (iv) such merger, consolidation, amalgamation or replacement
does not adversely affect the rights, preferences and privileges of the
holders of the Trust Securities (including any Successor Securities) in any
material respect (other than with respect to any dilution of the holders'
interest in the new entity), (v) such successor entity has a purpose identical
to that of the Trust, (vi) prior to such merger, consolidation, amalgamation
or replacement, McKesson has received an opinion of a nationally recognized
independent counsel to the Trust experienced in such matters to the effect
that: (A) such merger, consolidation, amalgamation or replacement does not
adversely affect the rights, preferences and privileges of the holders of the
Trust Securities (including any Successor Securities) in any material respect
(other than with respect to any dilution of the holders' interest in the new
entity), (B) following such merger, consolidation, amalgamation or
replacement, neither the Trust nor such successor entity will be required to
register as an investment company under the 1940 Act, and (C) following such
merger, consolidation, amalgamation or replacement, the Trust (or such
successor entity) will continue to be classified as a grantor trust for United
States federal income tax purposes and (vii) McKesson guarantees the
obligations of such successor entity under the Successor Securities at least
to the extent provided by the Guarantee and the Common Securities Guarantee
(as defined herein). Notwithstanding the foregoing, the Trust shall not,
except with the consent of holders of 100% in liquidation amount of the Trust
Securities, consolidate, amalgamate, merge with or into, or be replaced by any
other entity or permit any other entity to consolidate, amalgamate, merge with
or into, or replace it, if such consolidation, amalgamation, merger or
replacement would cause the Trust or the successor entity to be classified as
other than a grantor trust for United States federal income tax purposes.
 
 
                                      28
<PAGE>
 
REGISTRATION RIGHTS
 
  In connection with the Original Offering, McKesson and the Trust (together,
the "Registrants") entered into a registration rights agreement with the
Initial Purchaser (the "Registration Rights Agreement") pursuant to which the
Registrants, at McKesson's expense, agreed for the benefit of the holders of
the Convertible Preferred Securities, to (i) file with the commission the
Shelf Registration Statement covering resale of the Convertible Preferred
Securities, the Guarantee, the Convertible Debentures and the McKesson Common
Stock issuable upon conversion of the convertible securities within 90 days
after the latest date of original issuance of the Convertible Preferred
Securities, (ii) use their reasonable best efforts to cause the Shelf
Registration Statement to become effective as promptly as practicable and
(iii) use their reasonable best efforts to keep the Shelf Registration
Statement effective until the earlier of (a) the sale pursuant to the Shelf
Registration Statement or Rule 144 under the Securities Act of all the
Registrable Securities and (b) the expiration of the holding period applicable
to sales of Registrable Securities under Rule 144(k) under the Securities Act,
or any successor provision. The Registrants are permitted to suspend the use
of the prospectus which is a part of the Shelf Registration Statement for a
period not to exceed 60 days (whether or not consecutive) in any 12-month
period under certain circumstances relating to pending corporate developments,
public filings with the Commission and similar events, or because the
prospectus contains an untrue statement of a material fact or omits to state a
material fact required to be stated therein or necessary in order to make the
statements therein not misleading. The Registrants have agreed to pay a
Liquidated Damages Amount (as defined in the Registration Rights Agreement) to
holders of Registrable Securities if the Shelf Registration Statement is not
timely filed, or if the prospectus is unavailable for periods in excess of the
period set forth above, until such time as the Shelf Registration Statement is
filed or the prospectus is again made available, as the case may be. A holder
who wishes to sell Registerable Securities pursuant to the Shelf Registration
Statement is required to provide certain advance notification of such proposed
sales to the Company, and generally is required to be named as a selling
securityholder in the related prospectus, deliver a prospectus to purchasers
and be bound by those provisions of the Registration Rights Agreement that are
applicable to such holder (including indemnification provisions). In addition,
the Registration Rights Agreement provides that, if the prospectus contains an
untrue statement of a material fact or omits to state a material fact
necessary in order to make the statements therein not misleading, the
Registrants are to notify the holders to suspend the use of the prospectus
until such time as the Registrants have amended or supplemented the prospectus
so that it does not contain such material misstatement or omission, and the
holders are required to suspend their use of the prospectus during such
period. McKesson is to pay all expenses of the Shelf Registration Statement,
provide to each registered holder copies of such prospectus, notify each
registered holder when the Shelf Registration Statement has become effective
and take certain other actions as are required to permit, subject to the
foregoing, unrestricted resales of the Registrable Securities. The plan of
distribution of the Shelf Registration Statement permits resales of
Registrable Securities by selling securityholders through brokers and dealers.
However, neither McKesson nor the Trust is obligated under the Registration
Rights Agreement to pay certain costs and expenses, such as opinions of
counsel of such selling securityholders or accountants' "cold comfort"
letters, and neither the officers and directors of McKesson nor the trustees
of the Trust are obligated under the Registration Rights Agreement to
participate in marketing efforts on behalf of such selling securityholders.
 
  McKesson agreed in the Registration Rights Agreement to use its reasonable
best efforts to cause the Common Stock issuable upon conversion of the
Convertible Securities to be listed on each securities exchange or quotation
system on which the McKesson Common Stock is listed upon effectiveness of the
Shelf Registration Statement.
 
  The summary herein of certain provisions of the Registration Rights
Agreement does not purport to be complete and is subject to, and is qualified
in its entirety by reference to, all the provisions of the Registration Rights
Agreement, a copy of which is attached as an exhibit to the Registration
Statement of which this Prospectus forms a part and is available upon request
to McKesson.
 
                                      29
<PAGE>
 
FORM, DENOMINATION AND REGISTRATION
 
  The Convertible Preferred Securities were issued in fully registered form.
The description of book-entry procedures in this Prospectus includes summaries
of certain rules and operating procedures of The Depository Trust Company, New
York, New York ("DTC") that effect transfers of interest in the global
certificate or certificates issued in connection with sales of Convertible
Preferred Securities made pursuant to this Prospectus. Except for those sold
to institutional "accredited investors" (as defined in Rule 501(a)(1), (2),
(3) or (7) under the Securities Act), the Convertible Preferred Securities
were issued only as fully registered securities registered in the name of Cede
& Co. ("Cede") (as nominee for DTC). One or more fully registered global
Convertible Preferred Security certificates (the "Global Securities") will be
issued, representing, in the aggregate, Convertible Preferred Securities sold
pursuant to this Prospectus, and will be deposited with DTC. In the event of a
transfer of securities that were issued in fully registered, certificated
form, the holder of such certificates will be required to exchange them for
interests in the Global Certificates representing the number of Convertible
Preferred Securities being transferred. Except as set forth below, the record
ownership of the Global Security may be transferred, in whole or in part, only
to DTC, another nominee of DTC or to a successor of DTC or its nominee.
 
  Holders of Convertible Preferred Securities may hold their interests in the
Global Security directly through DTC, or indirectly through organizations
which are participants in DTC ("Participants"). Transfers between Participants
will be effected in the ordinary way in accordance with DTC rules and will be
settled in immediately available funds. Holders of Convertible Preferred
Securities who are not Participants may beneficially own interests in the
Global Security held by DTC only through Participants, or certain banks,
brokers, dealers, trust companies and other parties that clear through or
maintain a custodial relationship with a Participant, either directly or
indirectly ("Indirect Participants"). So long as Cede, as the nominee of DTC,
is the registered owner of the Global Security, Cede for all purposes will be
considered the sole holder of the Global Security. Except as provided below,
owners of beneficial interests in the Global Security will not be entitled to
have certificates registered in their names, will not receive or be entitled
to receive physical delivery of certificates in definitive form, and will not
be considered the holder thereof.
 
  Distributions on the Global Security will be made to Cede, the nominee for
DTC, as the registered owner of the Global Security by wire transfer of
immediately available funds. None of McKesson, the Trust or any Trustee will
have any responsibility or liability for any aspect of the records relating to
or payments made on account of beneficial ownership interests in the Global
Security or for maintaining, supervising or reviewing any records relating to
such beneficial ownership interests.
 
  DTC's practice is to credit Participants' accounts on the relevant payment
date with payments in amounts proportionate to their respective beneficial
interests in the Convertible Preferred Securities represented by the Global
Security as shown on the records of DTC (adjusted as necessary so that such
payments are made with respect to whole Convertible Preferred Securities
only), unless DTC has reason to believe that it will not receive payment on
such payment date. Payments by Participants to owners of beneficial interests
in Convertible Preferred Securities represented by the Global Security held
through such Participants will be the responsibility of such Participants, as
is now the case with securities held for the accounts of customers registered
in "street name."
 
  Beneficial holders of Convertible Preferred Securities who desire to convert
them into Underlying Common Stock (as defined herein) should contact their
brokers or other Participants or Indirect Participants to obtain information
on procedures, including proper forms and cut-off times, for submitting such
request. Because DTC can only act on behalf of Participants, who in turn act
on behalf of Indirect Participants, the ability of a person having a
beneficial interest in the Convertible Preferred Securities represented by the
Global Security to pledge such interest to persons or entities that do not
participate in the DTC system, or otherwise take actions in respect of such
interest, may be affected by the lack of a physical certificate evidencing
such interest.
 
                                      30
<PAGE>
 
  None of McKesson, the Trust or any Trustee (or any registrar, paying agent
or conversion agent) will have any responsibility for the performance by DTC
or its Participants or Indirect Participants of their respective obligations
under the rules and procedures governing their operations. DTC has advised
McKesson and the Trust that it will take any action permitted to be taken by a
holder of Convertible Preferred Securities (including, without limitation, the
presentation of Convertible Preferred Securities for conversion) only at the
direction of one or more Participants to whose account with DTC interests in
the Global Security are credited.
 
  DTC has advised McKesson and the Trust as follows: DTC is a limited purpose
trust company organized under the laws of the State of New York, a member of
the Federal Reserve System, a "clearing corporation" within the meaning of the
Uniform Commercial Code and a "clearing agency" registered pursuant to the
provisions of Section 17A of the Exchange Act. DTC was created to hold
securities for its Participants and to facilitate the clearance and settlement
of securities transactions between Participants through electronic book-entry
changes to accounts of its Participants, thereby eliminating the need for
physical movement of certificates. Participants include securities brokers and
dealers, banks, trust companies and clearing corporations and may include
certain other organizations such as the Initial Purchaser. Certain of such
Participants (or their representatives), together with other entities, own
DTC. Indirect access to the DTC system is available to others such as banks,
brokers, dealers and trust companies that clear through, or maintain a
custodial relationship with a Participant, either directly or indirectly.
 
  The laws of some jurisdictions require that certain purchasers of securities
take physical delivery of securities in definitive form. Such laws may impair
the ability to transfer beneficial interests in the Global Security.
 
  Conveyance of notices and other communications by DTC to Participants, by
Participants to Indirect Participants and Indirect Participants to beneficial
owners will be governed by arrangements among them, subject to any statutory
or regulatory requirements that may be in effect from time to time. Redemption
notices shall be sent to Cede. If less than all of the Convertible Preferred
Securities are being redeemed, DTC will reduce the amount of the interest of
each Participant in such Convertible Preferred Securities in accordance with
its procedures.
 
  Although voting with respect to the Convertible Preferred Securities is
limited, in those cases where a vote is required, neither DTC nor Cede will
itself consent or vote with respect to Convertible Preferred Securities. Under
its usual procedures, DTC would mail an Omnibus Proxy to the Trust as soon as
possible after the record date. The Omnibus Proxy assigns Cede consenting or
voting rights to those Participants to whose accounts the Convertible
Preferred Securities are credited on the record date (identified in a listing
attached to the Omnibus Proxy). McKesson and the Trust believe that the
arrangements among DTC, the Participants and Indirect Participants, and
beneficial owners will enable the beneficial owners to exercise rights
equivalent in substance to the rights that can be directly exercised by a
holder of a beneficial interest in the Trust.
 
  DTC may discontinue providing its services as securities depositary with
respect to the Convertible Preferred Securities at any time by giving notice
to the Trust. In the event that (i) DTC notifies the Trust that it is
unwilling or unable to continue as depositary for the Global Securities or if
at any time DTC ceases to be a clearing agency registered as such under the
Exchange Act when DTC is required to be so registered to act as such
depositary and no successor depositary shall have been appointed within 90
days of such notification or of the Trust becoming aware of DTC's ceasing to
be so registered, as the case may be, (ii) the Regular Trustees (with the
consent of the Company) in their sole discretion determine that the Global
Securities shall be exchanged for certificated Convertible Preferred
Securities or (iii) there shall have occurred and be continuing a Declaration
Event of Default, certificates for the Convertible Preferred Securities will
be printed and delivered in exchange for interests in the Global Securities.
Any Global Security that is exchangeable pursuant to the preceding sentence
shall be exchangeable for Convertible Preferred Securities registered in such
names as DTC shall direct. It is expected that such instructions will be based
upon directions received by DTC from its Participants with respect to
ownership of beneficial interests in such Global Security.
 
                                      31
<PAGE>
 
  The information in this section concerning DTC and DTC's book-entry system
has been obtained from sources that McKesson and the Trust believe to be
reliable, but neither McKesson nor the Trust takes responsibility for the
accuracy thereof.
 
INFORMATION CONCERNING THE INSTITUTIONAL TRUSTEE
 
  The Institutional Trustee, prior to the occurrence of a default with respect
to the Trust Securities and after the curing of any defaults that may have
occurred, undertakes to perform only such duties as are specifically set forth
in the Declaration and, after default, shall exercise the same degree of care
as a prudent person would exercise in the conduct of his or her own affairs.
Subject to such provisions, the Institutional Trustee is under no obligation
to exercise any of the powers vested in it by the Declaration at the request
of any holder of Convertible Preferred Securities, unless offered reasonable
indemnity by such holder against the costs, expenses and liabilities which
might be incurred thereby. The holders of Convertible Preferred Securities
will not be required to offer such indemnity in the event such holders, by
exercising their voting rights, direct the Institutional Trustee to take any
action it is empowered to take under the Declaration following a Declaration
Event of Default. The Institutional Trustee also serves as Guarantee Trustee
under the Guarantee and as Debt Trustee under the Indenture.
 
CONVERSION AGENT, PAYING AGENT, REGISTRAR AND TRANSFER AGENT
 
  The Institutional Trustee acts as Registrar, Transfer Agent, Conversion
Agent and Paying Agent for the Convertible Preferred Securities.
 
  Registration of transfers of Convertible Preferred Securities will be
effected without charge by or on behalf of the Trust, but upon payment in
respect of any tax or other government charges that may be imposed in relation
to it.
 
  The Trust will not be required to register or cause to be registered the
transfer of Convertible Preferred Securities after such Convertible Preferred
Securities have been selected for redemption.
 
GOVERNING LAW
 
  The Declaration and the Convertible Preferred Securities are governed by,
and construed in accordance with, the internal laws of the State of Delaware.
 
MISCELLANEOUS
 
  The Regular Trustees are authorized and directed to operate the Trust in
such a way so that the Trust will not be required to register as an
"investment company" under the 1940 Act or characterized as other than a
grantor trust for United States federal income tax purposes and so that the
Convertible Debentures will be treated as indebtedness of the Company for
United States federal income tax purposes. In this connection, McKesson and
the Regular Trustees are authorized to take any action, not inconsistent with
applicable law, the certificate of trust of the Trust, the Declaration or the
articles of incorporation of McKesson, that each of McKesson and the Regular
Trustees determine in their discretion to be necessary or desirable to achieve
such end, as long as such action does not adversely affect the interests of
the holders of the Convertible Preferred Securities or vary the terms thereof.
 
  Holders of the Convertible Preferred Securities have no preemptive rights.
 
                                      32
<PAGE>
 
                         DESCRIPTION OF THE GUARANTEE
 
  Set forth below is a summary of information concerning the Guarantee that
was executed and delivered by McKesson for the benefit of the holders from
time to time of Convertible Preferred Securities. The summary does not purport
to be complete and is subject in all respects to the provisions of, and is
qualified in its entirety by reference to, the Guarantee. The Guarantee
incorporates by reference the terms of the Trust Indenture Act. The Guarantee
will be qualified under the Trust Indenture Act. The Guarantee Trustee holds
the Guarantee for the benefit of the holders of the Convertible Preferred
Securities.
 
GENERAL
 
  Pursuant to and to the extent set forth in the Guarantee, McKesson agrees,
to the extent set forth therein, to pay in full to the holders of the
Convertible Preferred Securities (except to the extent paid by the Trust), as
and when due, regardless of any defense, right of set off or counterclaim
which the Trust may have or assert, the following payments (the "Guarantee
Payments"), without duplication: (i) all accrued and unpaid distributions that
are required to be paid on the Convertible Preferred Securities to the extent
the Trust has funds available therefor, (ii) the Redemption Price plus accrued
and unpaid distributions with respect to any Convertible Preferred Securities
called for redemption by the Trust, to the extent the Trust has funds
available therefor, and (iii) upon a voluntary or involuntary dissolution,
winding-up or termination of the Trust (other than in connection with the
distribution of Convertible Debentures to the holders of Convertible Preferred
Securities or the redemption of all the Convertible Preferred Securities), the
lesser of (a) the aggregate of the liquidation amount and all accrued and
unpaid distributions on the Convertible Preferred Securities to the date of
payment to the extent the Trust has funds available therefor and (b) the
amount of assets of the Trust remaining available for distribution to holders
of Convertible Preferred Securities then outstanding upon the liquidation of
the Trust. The holders of a majority in liquidation amount of the Convertible
Preferred Securities have the right to direct the time, method and place of
conducting any proceeding for any remedy available to the Guarantee Trustee or
to direct the exercise of any trust or power conferred upon the Guarantee
Trustee under the Guarantee. If the Guarantee Trustee fails to enforce the
Guarantee, any holder of Convertible Preferred Securities may directly
institute a legal proceeding against McKesson to enforce the Guarantee
Trustee's rights under the Guarantee without first instituting a legal
proceeding against the Trust, the Guarantee Trustee or any other person or
entity. If McKesson were to default on its obligation to pay amounts payable
on the Convertible Debentures, the Trust would lack available funds for the
payment of distributions or amounts payable on redemption of the Convertible
Preferred Securities or otherwise, and in such event holders of the
Convertible Preferred Securities would not be able to rely upon the Guarantee
for payment of such amounts. Instead, a holder of the Convertible Preferred
Securities would be required to rely on the enforcement (1) by the
Institutional Trustee of its rights, as registered holder of the Convertible
Debentures, against McKesson pursuant to the terms of the Convertible
Debentures or (2) by such holder of Convertible Preferred Securities of its
rights against McKesson to enforce payments on Convertible Debentures. See
"Description of the Convertible Debentures." The Declaration provides that
each holder of Convertible Preferred Securities, by acceptance thereof, agrees
to the provisions of the Guarantee, including the subordination provisions
thereof, and the Indenture.
 
  The Guarantee is a guarantee on a subordinated basis with respect to the
Convertible Preferred Securities from the time of issuance of such Convertible
Preferred Securities but does apply to any payment of distributions or
Redemption Price, or to payments upon the dissolution, winding-up or
termination of the Trust, except to the extent the Trust shall have funds
available therefor. If McKesson does not make interest payments on the
Convertible Debentures, the Trust will not pay distributions on the
Convertible Preferred Securities and will not have funds available therefor.
See "Risk Factors--Limitations of the Guarantee" and "Description of the
Convertible Debentures." The Guarantee, when taken together with McKesson's
obligations under the Convertible Debentures, the Indenture and the
Declaration, including its obligations to pay costs, expenses, debts and
liabilities of the Trust (other than with respect to the Trust Securities)
provides a full and unconditional guarantee on a subordinated basis by
McKesson on payments due on the Convertible Preferred Securities.
 
  McKesson has also agreed separately to irrevocably and unconditionally
guarantee the obligations of the Trust with respect to the Common Securities
(the "Common Securities Guarantee") to the same extent as the
 
                                      33
<PAGE>
 
Guarantee, except that upon the occurrence and during the continuation of a
Declaration Event of Default, holders of Convertible Preferred Securities
shall have priority over holders of Common Securities with respect to
Guarantee Payments.
 
CERTAIN COVENANTS OF MCKESSON
 
  In the Guarantee, McKesson has covenanted that, so long as any Convertible
Preferred Securities remain outstanding, if (i) the Company has exercised its
option to defer interest payments on the Convertible Debentures by extending
the interest payment period and such extension period, or any extension
thereof, shall be continuing, (ii) the Company shall be in default with
respect to its payment or other obligations under the Guarantee or (iii) there
shall have occurred and be continuing a Declaration Event of Default or any
event that, with the giving of notice or lapse of time or both, would
constitute a Declaration Event of Default, then McKesson shall not (a) declare
or pay dividends on, make distributions with respect to, or redeem, purchase
or acquire, or make a liquidation payment with respect to, any of its capital
stock or (b) make any payment of interest, principal or premium, if any, on or
repay, repurchase or redeem any debt securities of the Company that rank pari
passu with or junior in interest to the Convertible Debentures or make any
guarantee payment with respect to any guarantee by the Company of the debt
securities of any subsidiary of the Company if such guarantee ranks pari passu
with or junior in interest to the Convertible Debentures (other than (i) as a
result of a reclassification of McKesson capital stock or the exchange or
conversion of one class or series of McKesson capital stock for another class
or series of McKesson capital stock, (ii) the purchase of fractional interests
in shares of McKesson capital stock pursuant to the conversion or exchange
provisions of such capital stock of McKesson or the security being converted
into or exchanged for capital stock of McKesson, (iii) dividends or
distributions in McKesson Common Stock, (iv) any declaration of a dividend in
connection with the implementation of a stockholders' rights plan, or the
issuance of stock under any such plan in the future, or the redemption or
repurchase of any such rights pursuant thereto, (v) payments under the
Guarantee and Common Securities Guarantee, (vi) purchases of McKesson Common
Stock related to the issuance of McKesson Common Stock or rights under any of
the Company's benefit plans for its directors, officers or employees and (vii)
obligations under any dividend reinvestment and stock purchase plans).
 
  As part of the Guarantee, the Company agreed that it would honor all
obligations relating to the conversion of the Convertible Preferred Securities
into McKesson Common Stock as described in "Description of the Convertible
Preferred Securities--Conversion Rights."
 
AMENDMENTS AND ASSIGNMENT
 
  Except with respect to any changes that do not materially adversely affect
the rights of holders of Convertible Preferred Securities (in which case no
vote will be required), the Guarantee may be amended only with the prior
approval of the holders of at least a majority in liquidation amount of all
the Convertible Preferred Securities then outstanding. The manner of obtaining
any such approval of holders of the Convertible Preferred Securities will be
as set forth under "Description of the Convertible Preferred Securities--
Voting Rights." All guarantees and agreements contained in the Guarantee shall
bind the successors, assigns, receivers, trustees and representatives of
McKesson and shall inure to the benefit of the holders of the Convertible
Preferred Securities then outstanding. Except in connection with any permitted
merger or consolidation of McKesson with or into another entity or any
permitted sale, transfer or lease of McKesson's assets to another entity as
described under "Description of the Convertible Debentures--Certain
Covenants," the Company may not assign its rights or delegate its obligations
under the Guarantee without the prior approval of the holders of at least a
majority of the aggregate stated liquidation amount of the Convertible
Preferred Securities then outstanding.
 
TERMINATION OF THE GUARANTEE
 
  The Guarantee will terminate as to each holder of Convertible Preferred
Securities upon (i) full payment of the Redemption Price and accrued and
unpaid distributions with respect to all Convertible Preferred Securities,
(ii) distribution of the Convertible Debentures held by the Trust to the
holders of the Convertible Preferred
 
                                      34
<PAGE>
 
Securities, (iii) full payment of the amounts payable under the Declaration
upon liquidation of the Trust or (iv) the distribution of McKesson Common
Stock to such holder upon conversion of such holder's Convertible Preferred
Securities into McKesson Common Stock, and will terminate completely upon full
payment of the amounts payable in accordance with the Declaration. The
Guarantee will continue to be effective or will be reinstated, as the case may
be, if at any time any holder of Convertible Preferred Securities must restore
payment of any sum paid under such Convertible Preferred Securities or the
Guarantee.
 
EVENTS OF DEFAULT
 
  An event of default under the Guarantee will occur upon (a) the failure of
McKesson to perform any of its payment or other obligations thereunder or (b)
if applicable, the failure by McKesson to deliver McKesson Common Stock upon
an appropriate election by the holder or holders of Convertible Preferred
Securities to convert the Convertible Preferred Securities into shares of
McKesson Common Stock.
 
  The holders of a majority in liquidation amount of Convertible Preferred
Securities then outstanding relating to the Guarantee have the right to direct
the time, method and place of conducting any proceeding for any remedy
available to the Guarantee Trustee in respect of the Guarantee or to direct
the exercise of any trust or power conferred upon the Guarantee Trustee under
the Convertible Preferred Securities. If the Guarantee Trustee fails to
enforce the Guarantee, any holder of Convertible Preferred Securities may
institute a legal proceeding directly against McKesson to enforce the
Guarantee Trustee's rights under the Guarantee, without first instituting a
legal proceeding against the Trust, the Guarantee Trustee or any other person
or entity. Notwithstanding the foregoing, if McKesson has failed to make a
guarantee payment, a holder of Convertible Preferred Securities may directly
institute a proceeding against McKesson for enforcement of the Guarantee for
such payment. McKesson waives any right or remedy to require that any action
be brought first against the Trust or any other person or entity before
proceeding directly against McKesson.
 
STATUS OF THE GUARANTEE; SUBORDINATION
 
  The Guarantee constitutes an unsecured obligation of McKesson and ranks (i)
subordinate and junior in right of payment to all other liabilities of
McKesson (except any liabilities that may be pari passu expressly by their
terms), (ii) pari passu with the most senior preferred or preference stock now
or hereafter issued by McKesson and with any guarantee now or hereafter
entered into by McKesson in respect of any preferred or preference stock of
any affiliate of McKesson, and (iii) senior to McKesson Common Stock. The
terms of the Convertible Preferred Securities provide that each holder of
Convertible Preferred Securities issued by the Trust by acceptance thereof
agrees to the subordination provisions and other terms of the Guarantee
relating thereto. See, also, "Risk Factors--Subordinate Ranking of Obligations
Under the Guarantee and Convertible Debentures."
 
  The Guarantee constitutes a guarantee of payment and not of collection (that
is, the guaranteed party may institute a legal proceeding directly against the
Company to enforce its rights under the Guarantee without instituting a legal
proceeding against any other person or entity). The Guarantee does not place a
limitation on the amount of additional indebtedness that may be incurred by
McKesson. McKesson expects from time to time to incur additional indebtedness
senior to the Convertible Debentures.
 
INFORMATION CONCERNING THE GUARANTEE TRUSTEE
 
  The Guarantee Trustee, prior to the occurrence of a default with respect to
the Guarantee, undertakes to perform only such duties as are specifically set
forth in the Guarantee and, after default with respect to the Guarantee, shall
exercise the same degree of care as a prudent person would exercise in the
conduct of his or her own affairs. Subject to such provision, the Guarantee
Trustee is under no obligation to exercise any of the powers vested in it by
the Guarantee at the request of any holder of Convertible Preferred Securities
unless it is offered reasonable indemnity against the costs, expenses and
liabilities that might be incurred thereby.
 
GOVERNING LAW
 
  The Guarantee is governed by, and construed in accordance with, the laws of
the State of New York.
 
                                      35
<PAGE>
 
                   DESCRIPTION OF THE CONVERTIBLE DEBENTURES
 
  Set forth below is a description of certain terms of the Convertible
Debentures in which the Trust invested the proceeds from the issuance and sale
of the Trust Securities. The following description does not purport to be
complete and is subject to, and is qualified in its entirety by reference to
the Indenture entered into by McKesson and the Debt Trustee, a copy of which
may be obtained from McKesson upon request. Certain capitalized terms used
herein are defined in the Indenture. The Indenture will be qualified under the
Trust Indenture Act.
 
  Under certain circumstances involving the dissolution of the Trust following
the occurrence of a Special Event, Convertible Debentures may be distributed
to the holders of the Trust Securities in liquidation of the Trust. See
"Description of the Convertible Preferred Securities--Special Event
Distribution; Tax Event Redemption."
 
GENERAL
 
  The Convertible Debentures were issued as unsecured debt under the
Indenture. The Convertible Debentures are limited in aggregate principal
amount to $206,186,000, such amount being the sum of the aggregate stated
liquidation amount of the Convertible Preferred Securities and the capital
contributed by McKesson in exchange for the Common Securities.
 
  The Convertible Debentures are not subject to a sinking fund provision. The
entire principal amount of the Convertible Debentures will mature and become
due and payable, together with any accrued and unpaid interest thereon,
including Additional Sums (as defined herein), if any, and (to the extent
permitted by applicable law) Compound Interest, if any, on June 1, 2027.
McKesson has the right at any time to cause the Trust to be dissolved with the
result that, after satisfaction of creditors of the Trust, Convertible
Debentures with an aggregate principal amount equal to the aggregate stated
liquidation amount of the Convertible Preferred Securities and the Common
Securities would be distributed on a pro rata basis to the holders of the
Convertible Preferred Securities and the Common Securities in liquidation of
such holders' interests in the Trust, within 90 days following notice given to
the holders of the Convertible Preferred Securities, subject to the Regular
Trustees' having received an opinion of nationally recognized independent
counsel experienced in such matters to the effect that the holders will not
recognize any income, gain or loss for United States federal income tax
purposes as a result of the dissolution of the Trust and such distribution to
holders of Convertible Preferred Securities.
 
  If Convertible Debentures are distributed to holders of Convertible
Preferred Securities in liquidation of such holders' interests in the Trust,
such Convertible Debentures will initially be issued in the same form as the
Convertible Preferred Securities that such Convertible Debentures replace.
Under certain limited circumstances, Convertible Debentures may be issued in
certificated form in exchange for a Global Security. See "--Book-Entry and
Settlement" below. In the event that Convertible Debentures are issued in
certificated form, such Convertible Debentures will be in denominations of $50
and integral multiples thereof and may be transferred or exchanged at the
offices described below. Payments on Convertible Debentures issued as a Global
Security will be made to DTC, a successor depositary or, in the event that no
depositary is used, to a paying agent for the Convertible Debentures. With
respect to Convertible Debentures issued in certificated form, principal and
interest is payable, the transfer of the Convertible Debentures is registrable
and Convertible Debentures are exchangeable for Convertible Debentures of
other denominations of a like aggregate principal amount at the office or
agency of the Company maintained for such purpose in the Borough of Manhattan,
The City of New York; provided that payment of interest may be made at the
option of McKesson by check mailed to the address of the holder entitled
thereto or by wire transfer to an account appropriately designated by the
holder entitled thereto. Notwithstanding the foregoing, so long as the holder
of any Convertible Debenture is the Institutional Trustee, the payment of
principal and interest on such Convertible Debenture will be made at such
place and to such account as may be designated by the Institutional Trustee.
 
  The Indenture does not contain provisions that afford holders of the
Convertible Debentures protection in the event of a highly levered transaction
involving McKesson that would adversely affect such holders.
 
                                      36
<PAGE>
 
INTEREST
 
  Each Convertible Debenture shall bear interest at the rate of 5% per annum
from the first date of original issuance, payable quarterly in arrears on
March 1, June 1, September 1 and December 1 of each year (each an "Interest
Payment Date"), commencing June 1, 1997, to the person in whose name such
Convertible Debenture is registered, subject to certain exceptions, 15 days
prior to such Interest Payment Date.
 
  The amount of interest payable for any period will be computed on the basis
of a 360-day year of twelve 30-day months. The amount of interest payable for
any period shorter than a full quarterly period for which interest is computed
will be computed on the basis of the actual number of days elapsed per 30-day
month. In the event that any date on which interest is payable on the
Convertible Debentures is not a Business Day, then payment of the interest
payable on such date will be made on the next succeeding day that is a
Business Day (and without any interest or other payment in respect of any such
delay), except that, if such Business Day is in the next succeeding calendar
year, then such payment shall be made on the immediately preceding Business
Day, in each case with the same force and effect as if made on such date.
 
OPTION TO EXTEND INTEREST PAYMENT PERIOD
 
  So long as McKesson shall not be in default in the payment of interest on
the Convertible Debentures, McKesson shall have the right at any time, and
from time to time, during the term of the Convertible Debentures to defer
payments of interest by extending the interest payment period for a period not
exceeding 20 consecutive quarters, at the end of which Extension Period
McKesson shall pay all interest then accrued and unpaid; together with
interest thereon compounded quarterly at the rate specified for the
Convertible Debentures to the extent permitted by applicable law ("Compound
Interest") and any Additional Sums; provided that during any such Extension
Period, McKesson shall not (a) declare or pay dividends on, make any
distributions with respect to, or redeem, purchase, acquire or make a
liquidation payment with respect to, any of its capital stock or (b) make any
payment of interest, principal or premium, if any, on or repay, repurchase or
redeem any debt securities issued by McKesson that rank pari passu with or
junior in interest to the Convertible Debentures or make any guarantee
payments with respect to any guarantee by the Company of the debt securities
of any subsidiary of the Company if such guarantee ranks pari passu with or
junior in interest to the Convertible Debentures (other than (i) as a result
of a reclassification of McKesson capital stock or the exchange or conversion
of one class or series of McKesson capital stock for another class or series
of McKesson capital stock, (ii) the purchase of fractional interests in shares
of McKesson capital stock pursuant to the conversion or exchange provisions of
such McKesson capital stock or the security being converted into or exchanged
for McKesson capital stock, (iii) dividends or distributions in common stock
of the Company, (iv) any declaration of a dividend in connection with the
implementation of a stockholders' rights plan, or the issuance of stock under
any such plan in the future, or the redemption or repurchase of any such
rights pursuant thereto, (v) payments under the Guarantee and Common
Securities Guarantee, (vi) purchases of common stock related to the issuance
of common stock or rights under any of the Company's benefit plans for its
directors, officers or employees and (vii) obligations under any dividend
reinvestment and stock purchase plans). Prior to the termination of any such
Extension Period, McKesson may further defer payments of interest by extending
the interest payment period; provided, however, that, such Extension Period,
including all such previous and further extensions, may not exceed 20
consecutive quarters or extend beyond the maturity of the Convertible
Debentures. Upon the termination of any Extension Period and the payment of
all amounts then due, McKesson may commence a new Extension Period, subject to
the terms set forth in this section. Each Extension Period, if any, will end
on an Interest Payment Date. No interest shall be due and payable during an
Extension Period, except on the last day thereof, but McKesson may prepay at
any time all or any portion of the interest accrued during an Extension
Period. On the last day of each Extension Period, all accrued and unpaid
interest (including Additional Sums, if any, and, to the extent permitted by
applicable law, Compound Interest) shall be due and payable and shall be paid
to the holders of record of the Convertible Debentures at the close of
business on the record date next preceding such Interest Payment Date.
McKesson has no present intention of exercising its right to defer payments of
interest by extending the interest payment period on the Convertible
Debentures. If the Institutional Trustee shall be the sole holder of the
Convertible Debentures, McKesson shall give the Regular Trustees, the
Institutional Trustee and the Debt
 
                                      37
<PAGE>
 
Trustee notice of its selection of such Extension Period at least one Business
Day prior to the earlier of (i) the date distributions on the Convertible
Preferred Securities are payable or (ii) the date the Regular Trustees are
required to give notice to any applicable self-regulatory organization or to
holders of the Convertible Preferred Securities of the record or payment date
of such related distribution, but in any event not less than 10 Business Days
prior to such record date. McKesson shall cause the Trust to give notice of
McKesson's selection of such Extension Period to holders of the Convertible
Preferred Securities. If the Institutional Trustee shall not be the sole
holder of the Convertible Debentures, McKesson shall give the Debt Trustee,
the Institutional Trustee and the holders of the Convertible Debentures notice
of its selection of such Extension Period at least 10 Business Days prior to
the earlier of (i) the next succeeding Interest Payment Date and (ii) the date
McKesson is required to give notice to any applicable self-regulatory
organization or to holders of Convertible Debentures of the record or payment
date of such related interest payment, but in any event not less than two
Business Days prior to such record date.
 
ADDITIONAL SUMS
 
  If at any time the Trust shall be required to pay any taxes, duties,
assessments or governmental charges of whatever nature (other than withholding
taxes) imposed by the United States, or any other taxing authority, then, in
any such case, McKesson will pay as additional sums ("Additional Sums") such
additional amounts as shall be required so that the net amounts received and
retained by the Trust after paying any such taxes, duties, assessments or
other governmental charges will be not less than the amounts the Trust would
have received had no such taxes, duties, assessments or other governmental
charges been imposed so long as the Trust is the holder of the Convertible
Debentures.
 
PROPOSED TAX LEGISLATION
 
  Please refer to discussion above under the heading "Description of the
Convertible Preferred Securities--Proposed Tax Legislation."
 
SUBORDINATION
 
  The Indenture provides that the Convertible Debentures are subordinated and
junior in right of payment to all existing and future Senior Indebtedness of
McKesson. No payment of principal (including redemption payments, if any),
premiums, if any, or interest on the Convertible Debentures may be made (i) if
any principal, premium if any, interest or any other payment due on any Senior
Indebtedness of McKesson is not paid when due and any applicable grace period
with respect to such default has ended with such default not having been cured
or waived or ceasing to exist or (ii) if the maturity of any Senior
Indebtedness of McKesson has been accelerated because of a default and such
acceleration has not been rescinded.
 
  Upon any distribution of assets of McKesson to creditors upon any
dissolution, winding-up, liquidation or reorganization, whether voluntary or
involuntary, or in bankruptcy, insolvency, receivership or other proceedings,
all principal, premium, if any, and interest due or to become due on all
Senior Indebtedness of McKesson must be paid in full before the holders of
Convertible Debentures are entitled to receive or retain any payment. Upon
satisfaction of all claims of all Senior Indebtedness then outstanding, the
rights of the holders of the Convertible Debentures will be subrogated to the
rights of the holders of Senior Indebtedness of McKesson to receive payments
or distributions applicable to Senior Indebtedness until all amounts owing on
the Convertible Debentures are paid in full.
 
  The term "Senior Indebtedness" means, with respect to McKesson, (i) the
principal, premium, if any, and interest in respect of (A) indebtedness of
such obligor for money borrowed (but excluding trade accounts payable arising
in the ordinary course of business) under any credit agreements, notes,
guarantees or similar documents and (B) indebtedness evidenced by securities,
debentures, bonds or other similar instruments issued by such obligor, (ii)
all capital lease obligations of such obligor, (iii) all obligations of such
obligor issued or assumed as the deferred purchase price of property, all
conditional sale obligations of such obligor and all obligations of
 
                                      38
<PAGE>
 
such obligor under any title retention agreement (but excluding trade accounts
payable arising in the ordinary course of business), (iv) all obligations of
such obligor for the reimbursement on any letter of credit, bankers'
acceptance, security purchase facility or similar credit transaction, (v) all
obligations of such obligor (contingent or otherwise) with respect to an
interest rate or other swap, cap or collar agreements or other similar
instruments or agreements or foreign currency hedge, exchange, purchase or
similar instruments or agreements, (vi) all obligations of the types referred
to in clauses (i) through (v) above of other persons for the payment of which
such obligor is responsible or liable as obligor, guarantor or otherwise and
(vii) all obligations of the types referred to in clauses (i) through (vi)
above of other persons secured by any lien on any property or asset of such
obligor (whether or not such obligation is assumed by such obligor), whether
outstanding on the date of the Indenture or thereafter created, incurred,
assumed, guaranteed or in effect guaranteed by such obligor, except for any
such indebtedness that is by its terms subordinated to or pari passu with the
Convertible Debentures. Such Senior Indebtedness shall continue to be Senior
Indebtedness and be entitled to the benefits of the subordination provisions
irrespective of any deferrals, renewals, extensions or refundings of, or
amendments, modifications, supplements or waivers of any term of such Senior
Indebtedness. There was approximately $825 million of Senior Indebtedness
outstanding as of March 31, 1997.
 
  The Indenture does not limit the aggregate amount of Senior Indebtedness
that may be issued by McKesson.
 
  In the event of (i) any insolvency, bankruptcy, receivership, liquidation,
reorganization, readjustment, composition or other similar proceeding relating
to the Company, its creditors or its property, (ii) any proceeding for the
liquidation, dissolution or other winding up of the Company voluntary or
involuntary, whether or not involving insolvency or bankruptcy proceedings,
(iii) any assignment by the Company for the benefit of creditors or (iv) any
other marshalling of the assets of the Company, all Senior Indebtedness
(including any interest thereon accruing after the commencement of any such
proceedings) shall first be paid in full before any payment or distribution,
whether in cash, securities or other property, shall be made on account of the
principal of or premium, if any, or interest, if any, on the Convertible
Debentures. In such event, any payment or distribution on account of the
principal of or premium, if any, or interest, on the Convertible Debentures,
whether in cash, securities or other property (other than securities of the
Company or any other corporation provided for by a plan of reorganization or
readjustment the payment of which is subordinate, at least to the extent
provided in the subordination provisions with respect to the Convertible
Debentures, to the payment of all Senior Indebtedness at the time outstanding,
and to any securities issued in respect thereof under any such plan of
reorganization or readjustment), which would otherwise (but for the
subordination provisions) be payable or deliverable in respect of the
Convertible Debentures shall be paid or delivered directly to the holders of
Senior Indebtedness in accordance with the priorities then existing among such
holders until all Senior Indebtedness (including any interest thereon accruing
after the commencement of any such proceedings) shall have been paid in full.
 
  In the event of any such proceeding, after payment in full of all sums owing
with respect to Senior Indebtedness the holders of Convertible Debentures,
together with the holders of any obligations of the Company ranking on a
parity with the Convertible Debentures, shall be entitled to be paid from the
remaining assets of the Company the amounts at the time due and owing on
account of unpaid principal of and premium, if any, and interest, if any, on
the Convertible Debentures and such other obligations before any payment or
other distribution, whether in cash, property or otherwise, shall be made on
account of any capital stock or obligations of the Company ranking junior to
the Convertible Debentures and such other obligations. If any payment or
distribution on account of the principal of or interest on the Convertible
Debentures of any character or any security, whether in cash, securities or
other property (other than securities of the Company or any other corporation
provided for by a plan of reorganization or readjustment the payment of which
is subordinate, at least to the extent provided in the subordination
provisions with respect to the Convertible Debentures, to the payment of all
Senior Indebtedness at the time outstanding and to any securities issued in
respect thereof under any such plan of reorganization or readjustment) shall
be received by the Debt Trustee or any holder of any Convertible Debentures in
contravention of any of the terms hereof and before all the Senior
Indebtedness shall have been paid in full, such payment or distribution or
security shall be received in trust for the benefit of, and shall be paid over
or delivered and transferred to, the holders of the Senior Indebtedness at the
time outstanding
 
                                      39
<PAGE>
 
in accordance with the priorities then existing among such holders and
creditors for application to the payment of all Senior Indebtedness remaining
unpaid to the extent necessary to pay all such Senior Indebtedness in full. By
reason of such subordination, in the event of the insolvency of the Company
holders of Senior Indebtedness may receive more, ratably, and holders of the
Convertible Debentures having a claim pursuant to such securities may receive
less, ratably, than the other creditors of the Company. Such subordination
will not prevent the occurrence of any Event of Default in respect of the
Convertible Debentures.
 
CERTAIN COVENANTS
 
  In the Indenture, McKesson has covenanted that, so long as any Convertible
Debentures are outstanding, if (i) there shall have occurred and be continuing
any Indenture Event of Default or any event that, with the giving of notice or
lapse of time or both, would constitute an Indenture Event of Default, (ii)
McKesson shall be in default with respect to its payment or other obligations
under the Guarantee, or (iii) McKesson shall have given notice of its election
to defer interest payments on the Convertible Debentures by extending the
interest payment period and such period, or any extension thereof, shall be
continuing, then McKesson (a) shall not declare or pay dividends on, make
distributions with respect to, or redeem, purchase or acquire, or make a
liquidation payment with respect to, any of its capital stock or (b) shall not
make any payment of interest, principal or premium, if any, on or repay,
repurchase or redeem any debt securities issued by McKesson that rank pari
passu with or junior in interest to the Convertible Debentures or make any
guarantee payments with respect to any guarantee by the Company of the debt
securities of any subsidiary of the Company if such guarantee ranks pari passu
with or junior in interest to the Convertible Debentures (other than (i) as a
result of a reclassification of McKesson capital stock or the exchange or
conversion of one class or series of McKesson capital stock for another class
or series of McKesson capital stock, (ii) the purchase of fractional interests
in shares of McKesson capital stock pursuant to the conversion or exchange
provisions of such capital stock of McKesson or the security being converted
or exchanged for McKesson capital stock, (iii) dividends or distributions in
Common Stock of the Company, (iv) any declaration of a dividend in connection
with the implementation of a stockholders' rights plan, or the issuance of
stock under any such plan in the future, or the redemption or repurchase of
any such rights pursuant thereto, (v) payments under the Guarantee and Common
Securities Guarantee, (vi) purchases of Common Stock related to the issuance
of Common Stock or rights under any of the Company's benefit plans for its
directors, officers or employees and (vii) obligations under any dividend
reinvestment and stock purchase plan).
 
  McKesson has covenanted (i) to directly or indirectly maintain 100%
ownership of the Trust's Common Securities; provided, however, that any
permitted successor of McKesson under the Indenture may succeed to McKesson's
ownership of such Common Securities, (ii) to use its reasonable efforts to
cause the Trust (x) to remain a statutory business trust, except in connection
with the distribution of Convertible Debentures to the holders of Trust
Securities in liquidation of the Trust, the redemption of all the Trust
Securities of the Trust, or certain mergers, consolidations or amalgamations,
each as permitted by the Declaration, and (y) to continue to be classified as
a grantor trust for United States federal income tax purposes and (iii) to use
its reasonable efforts to cause each holder of Trust Securities to be treated
as owning an undivided beneficial interest in the Convertible Debentures.
 
  The Indenture provides that McKesson will not merge or consolidate with or
into any other person or entity or sell, transfer, lease or otherwise convey
all or substantially all of its assets on a consolidated basis to any person
unless (a)(i) McKesson is the surviving corporation in any such merger or (ii)
if McKesson is not the survivor, the successor is a corporation organized and
existing under the laws of the United States of America, any state thereof or
the District of Columbia and expressly assumes the due and punctual payment of
the principal of, premium, if any, and interest (including Additional Sums and
Compound Interest) on all Convertible Debentures issued thereunder and the
performance of every other covenant and agreement in the Indenture and the
Registration Rights Agreement on the part of the Company, (b) immediately
thereafter no Indenture Event of Default and no event which, after notice or
lapse of time or both, would become an Indenture Event of Default shall have
occurred and be continuing, and (c) McKesson has delivered to the Debt Trustee
the officers'
 
                                      40
<PAGE>
 
certificate and opinion of counsel required by the Indenture. Upon any such
consolidation, merger, sale, transfer, lease or conveyance, the successor
corporation shall succeed to and be substituted for McKesson under the
Indenture and thereafter (except in the case of a lease) the predecessor
corporation shall be relieved of all obligations and covenants under the
Indenture, the Convertible Debentures and the Registration Rights Agreement.
 
REDEMPTION AT THE OPTION OF MCKESSON
 
  McKesson has the right to redeem the Convertible Debentures, in whole or in
part, from time to time, on or after March 4, 2000, upon not less than 30 nor
more than 60 days notice, at the following prices (expressed as percentages of
the principal amount of the Convertible Debentures), together with accrued and
unpaid interest (including Additional Sums, if any, and, to the extent
permitted by applicable law, Compound Interest, if any), to but excluding the
redemption date, if redeemed during the 12-month period beginning March 4 of
the applicable year set forth below:
 
<TABLE>
<CAPTION>
            YEAR                         REDEMPTION PRICE
            ----                         ----------------
            <S>                          <C>
            2000........................      103.5%
            2001........................      103.0
            2002........................      102.5
            2003........................      102.0
            2004........................      101.5
            2005........................      101.0
            2006........................      100.5
</TABLE>
 
and 100.0% if redeemed on or after March 4, 2007.
 
  McKesson may not redeem fewer than all of the outstanding Convertible
Debentures unless all accrued and unpaid interest has been paid on all
Convertible Debentures for all quarterly interest payment periods terminating
on or prior to the date of redemption. If Convertible Debentures are redeemed
on any interest payment date, accrued and unpaid interest shall be payable to
holders of record on the relevant record date.
 
  McKesson also has the right to redeem the Convertible Debentures, in whole
or in part, at any time in certain circumstances upon the occurrence of a Tax
Event as described under "Description of the Convertible Preferred
Securities--Special Event Distribution; Tax Event Redemption" at 100% of the
principal amount thereof, together with accrued and unpaid interest (including
Additional Sums, if any, and, to the extent permitted by applicable law,
Compound Interest, if any) to the Redemption Date.
 
  Any redemption of Convertible Debentures shall be made on not less than 30
nor more than 60 days notice to holders of the Convertible Debentures. In the
event that fewer than all of the outstanding Convertible Debentures are to be
redeemed, the Convertible Debentures will be redeemed pro rata. So long as the
corresponding Trust Securities are outstanding, the proceeds from the
redemption of the Convertible Debentures will be used to redeem the Trust
Securities.
 
CONVERSION OF THE CONVERTIBLE DEBENTURES
 
  The Convertible Debentures are convertible into McKesson Common Stock at the
option of the holders of the Convertible Debentures at any time beginning May
21, 1997 and prior to the close of business on the Business Day prior to the
maturity date of the Convertible Debentures (or, in the case of Convertible
Debentures called for redemption, the close of business on the Business Day
prior to the Redemption Date) at an initial conversion rate of .6709 shares of
McKesson Common Stock for each $50 in principal amount of Convertible
Debentures (equivalent to a conversion price of $74.53 per share of McKesson
Common Stock), subject to adjustment and reset as described under "Description
of the Convertible Preferred Securities--Conversion Rights." The Trust has
agreed not to convert Convertible Debentures held by it except pursuant to a
notice of
 
                                      41
<PAGE>
 
conversion delivered to the Conversion Agent by a holder of Convertible
Preferred Securities. Upon surrender of a Convertible Preferred Security to
the Conversion Agent for conversion, the Trust will distribute $50 principal
amount of Convertible Debentures for each $50 in liquidation amount of
Convertible Preferred Securities surrendered to the Conversion Agent on behalf
of the holder of the Convertible Preferred Securities so converted, whereupon
the Conversion Agent will convert such Convertible Debentures into McKesson
Common Stock on behalf of such holder. McKesson's delivery to the holders of
the Convertible Debentures (through the Conversion Agent) of the fixed number
of shares of McKesson Common Stock into which the Convertible Debentures are
convertible (together with the cash payment, if any, in lieu of fractional
shares) will be deemed to satisfy McKesson's obligation to pay the principal
amount of the Convertible Debentures so converted, and the accrued and unpaid
interest thereon attributable to the period from the last date to which
interest has been paid or duly provided for; provided, however, that if any
Convertible Debenture is converted after the close of business on a record
date for payment of interest, the interest payable on the related Interest
Payment Date with respect to such Convertible Debenture shall be paid on such
Interest Payment Date to the person who was the registered holder thereof on
such record date, despite such conversion, unless such Convertible Debenture
has been called for redemption on a Redemption Date falling between such
record date and the corresponding Interest Payment Date, in which case the
amount of such payment shall include interest accrued to, but excluding, such
Redemption Date and such payment shall be made to the converting holder.
 
INDENTURE EVENTS OF DEFAULT
 
  The Indenture provides that any one or more of the following described
events, which has occurred and is continuing, constitutes an "Indenture Event
of Default" with respect to the Convertible Debentures: (i) failure for 30
days to pay interest on the Convertible Debentures, including any Additional
Sums, Compound Interest and Liquidated Damages in respect thereof, when due;
provided that a valid extension of an interest payment period will not
constitute a default in the payment of interest (including any Additional
Sums, Compound Interest or Liquidated Damages) for this purpose; or (ii)
failure to pay principal of or premium, if any, on the Convertible Debentures
when due whether at maturity, upon redemption, by declaration or otherwise, or
(iii) failure by McKesson to deliver shares of McKesson Common Stock upon an
election by a holder of Convertible Preferred Securities or Convertible
Debentures to convert such Convertible Preferred Securities or Convertible
Debentures, as the case may be, (iv) failure to observe or perform any other
covenant contained in the Indenture for 30 days after notice to McKesson by
the Debt Trustee or by the holders of at least 25% in aggregate outstanding
principal amount of the Convertible Debentures; (v) the dissolution, winding
up or termination of the Trust, except in connection with the distribution of
Convertible Debentures to the holders of Convertible Preferred Securities in
liquidation of the Trust upon the occurrence of a Special Event or upon the
occurrence of events as described under "Description of the Convertible
Preferred Securities--Liquidation of Trust and Distribution of Convertible
Debentures to Holders," upon the redemption of all outstanding Convertible
Preferred Securities, upon the conversion of all outstanding Convertible
Preferred Securities into McKesson Common Stock or in connection with certain
mergers, consolidations or amalgamations permitted by the Declaration; or (vi)
certain events of bankruptcy, insolvency or reorganization of McKesson which
are voluntary or, if involuntary, continue for a period of 90 days.
 
  If any Indenture Event of Default shall occur and be continuing, the
Institutional Trustee or the holders of not less than 25% in aggregate
principal amount of the Convertible Debentures then outstanding may declare
the principal of and the accrued and unpaid interest on the Convertible
Debentures (including Additional Sums, if any, and (to the extent permitted by
applicable law) Compound Interest, if any) and any other amounts payable under
the Indenture to be forthwith due and payable and to enforce its other rights
as a creditor with respect to the Convertible Debentures; provided, however,
that after such acceleration, but before a judgment or decree based on such
acceleration is obtained, the holders of a majority in aggregate principal
amount of the Convertible Debentures then outstanding may, under certain
circumstances, rescind and annul such acceleration if all Indenture Events of
Default, other than the nonpayment of accelerated principal and interest, have
been cured or waived as provided in the Indenture. An Indenture Event of
Default also constitutes a Declaration Event of Default. The holders of
Convertible Preferred Securities in certain circumstances have the right to
direct the Institutional Trustee to exercise its rights as the holder of the
Convertible Debentures. See "Description of the
 
                                      42
<PAGE>
 
Convertible Preferred Securities--Declaration Events of Default" and "--Voting
Rights." Notwithstanding the foregoing, if an Indenture Event of Default has
occurred and is continuing and such event is attributable to the failure of
McKesson to pay interest or principal on the Convertible Debentures on the
date such interest or principal is otherwise payable (or in the case of
redemption, the Redemption Date), then a holder of Convertible Preferred
Securities may institute a Direct Action for payment on or after the
respective due dates specified in the Convertible Debentures. Notwithstanding
any payments made to such holder of Convertible Preferred Securities by
McKesson in connection with a Direct Action, McKesson shall remain obligated
to pay the principal of and interest on the Convertible Debentures held by the
Trust or the Institutional Trustee of the Trust, and McKesson shall be
subrogated to the rights of the holder of such Convertible Preferred
Securities with respect to payments on the Convertible Preferred Securities to
the extent of any payments made by McKesson to such holder in any Direct
Action. The holders of Convertible Preferred Securities will not be able to
exercise directly any other remedy available to the holders of the Convertible
Debentures.
 
  The Indenture contains provisions permitting the holders of a majority in
aggregate principal amount of the Convertible Debentures then outstanding, on
behalf of all of the holders of the Convertible Debentures, to waive any past
default in the performance of any of the covenants contained in the Indenture,
except a default in the payment of the principal of or premium, if any, or
interest on any of the Convertible Debentures and certain other defaults;
provided, however, that if the Convertible Debentures are held by the Trust or
the Institutional Trustee of the Trust, such waiver shall not be effective
until the holders of a majority in aggregate liquidation amount of Trust
Securities shall have consented to such waiver; provided, further, that if the
consent of the holder of each outstanding Convertible Debenture affected is
required, such waiver shall not be effective until each holder of the Trust
Securities shall have consented to such waiver.
 
  A default under any other indebtedness of the Company would not constitute
an Indenture Event of Default.
 
  Subject to the provisions of the Indenture relating to the duties of the
Debt Trustee in case an Indenture Event of Default shall occur and be
continuing, the Debt Trustee is under no obligation to exercise any of its
rights or powers under the Indenture at the request or direction of any
holders of Convertible Debentures, unless such holders shall have offered to
the Debt Trustee reasonable indemnity. Subject to such provisions for the
indemnification of the Debt Trustee, the holders of a majority in aggregate
principal amount of the Convertible Debentures then outstanding have the right
to direct the time, method and place of conducting any proceeding for any
remedy available to the Debt Trustee, or exercising any trust or power
conferred on the Debt Trustee.
 
  No holder of any Convertible Debenture has any right to institute any
proceeding with respect to the Indenture or for any remedy thereunder, unless
(i) such holder shall have previously given to the Debt Trustee written notice
of a continuing Indenture Event of Default, (ii) if the Trust is not the sole
holder of Convertible Debentures, the holders of at least 25% in aggregate
principal amount of the Convertible Debentures then outstanding shall have
made written request to the Debt Trustee to institute proceedings, (iii) such
holder has offered reasonable indemnity to the Debt Trustee to institute such
proceeding as Indenture Trustee, (iv) the Debt Trustee shall have failed to
institute such proceeding within 60 days of such notice and offer of
indemnity, and (v) the Debt Trustee shall not have received from the holders
of a majority in aggregate principal amount of the outstanding Convertible
Debentures a direction inconsistent with such request. However, such
limitations do not apply to a suit instituted by a holder of a Convertible
Debenture for enforcement of payment of the principal of, premium, if any, or
interest on such Convertible Debenture on or after the respective due dates
expressed in such Convertible Debenture.
 
  The Company is required to file annually with the Debt Trustee and the
Institutional Trustee a certificate as to whether or not the Company is in
compliance with all the conditions and covenants under the Indenture.
 
BOOK-ENTRY AND SETTLEMENT
 
  If distributed to holders of Convertible Preferred Securities in connection
with the involuntary or voluntary dissolution, winding-up or liquidation of
the Trust as a result of the occurrence of a Special Event, the
 
                                      43
<PAGE>
 
Convertible Debentures will be issued in the same form as the Convertible
Preferred Securities that such Convertible Debentures replace. Except under
the limited circumstances described below, Convertible Debentures represented
by a global security (a "Global Debenture") are not exchangeable for, and are
not otherwise issuable as, Convertible Debentures in definitive form. The
Global Debenture may not be transferred except by DTC to a nominee of DTC or
by a nominee of DTC to DTC or another nominee of DTC or to successor
depositary or its nominee.
 
  The laws of some jurisdictions require that certain purchasers of securities
take physical delivery of such securities in definitive form. Such laws may
impair the ability to transfer or pledge beneficial interests in a Global
Debenture.
 
  Except as provided below, owners of beneficial interests in a Global
Debenture are not entitled to receive physical delivery of Convertible
Debentures in definitive form and are not considered the holders (as defined
in the Indenture) thereof for any purpose under the Indenture, and no Global
Debenture representing Convertible Debentures shall be exchangeable, except
for another Global Debenture of like denomination and tenor to be registered
in the name of DTC or its nominee or a successor depositary or its nominee.
Accordingly, each beneficial owner must rely on the procedures of DTC or if
such person is not a Participant, on the procedures of the Participant through
which such person owns its interest to exercise any rights of a holder under
the Indenture.
 
THE DEPOSITARY
 
  If Convertible Debentures are distributed to holders of Convertible
Preferred Securities in liquidation of such holders' interests in the Trust
and a Global Debenture is issued, DTC will act as securities depositary for
the Global Debenture. For a description of DTC and the specific terms of the
depositary arrangements, see "Description of the Convertible Preferred
Securities--Form, Denomination and Registration--Global Convertible Preferred
Securities; Book-Entry Form." As of the date of this Prospectus, the
description therein of DTC's book-entry system and DTC's practices as they
relate to purchases, transfers, notices and payments with respect to the
Convertible Preferred Securities apply in all material respects to any debt
obligations represented by one or more global securities held by DTC. McKesson
may appoint a successor to DTC or any successor depositary in the event DTC or
such successor depositary is unable or unwilling to continue as a depositary
for such Global Debenture.
 
  None of McKesson, the Trust, the Debt Trustee, any paying agent and any
other agent of McKesson or the Debt Trustee have any responsibility or
liability for any aspect of the records relating to or payments made on
account of beneficial ownership interests in a Global Debenture or for
maintaining, supervising or reviewing any records relating to such beneficial
ownership interests.
 
DISCONTINUANCE OF THE DEPOSITARY'S SERVICES
 
  DTC may discontinue providing its services as securities depositary with
respect to the Global Debenture at any time by giving notice to the Company.
In the event that (i) DTC notifies the Company that it is unwilling or unable
to continue as a depositary for the Global Debenture or if at any time DTC
ceases to be a clearing agency registered as such under the Securities
Exchange Act of 1934 when DTC is required to be so registered to act as such
depositary and no successor depositary shall have been appointed within 90
days of such notification or of the Company becoming aware of DTC's ceasing to
be so registered, as the case may be, (ii) the Company in its sole discretion
determines that the Global Debenture shall be exchanged for certificated
Convertible Debentures or (iii) there shall have occurred and be continuing an
Indenture Event of Default, certificates for the Convertible Debentures will
be printed and delivered in exchange for interests in the Global Debentures.
Any Global Debenture that is exchangeable pursuant to the preceding sentence
shall be exchangeable for Convertible Debentures registered in such names as
DTC shall direct. It is expected that such instructions will be based upon
directions received by DTC from its Participants with respect to ownership of
beneficial interests in such Global Debenture.
 
                                      44
<PAGE>
 
MODIFICATIONS AND AMENDMENTS OF THE INDENTURE
 
  The Indenture contains provisions permitting the Company and the Debt
Trustee, with the consent of the holders of not less than a majority in
aggregate principal amount of the outstanding Convertible Debentures, to
modify the Indenture or the rights of the holders of Convertible Debentures;
provided, however, that no such modification may, without the consent of the
holder of each outstanding Convertible Debenture affected thereby, (i) extend
the stated maturity of the Convertible Debentures or reduce the principal
amount thereof, or reduce the rate or extend the time for payment of interest
thereon, or reduce any premium payable upon the redemption thereof, or
adversely affect the right to convert Convertible Debentures or the
subordination provisions of the Indenture, or (ii) reduce the percentage in
aggregate principal amount of outstanding Convertible Debentures, the holders
of which are required to consent to any such supplemental indenture.
 
  In addition, the Company and the Debt Trustee may execute, without the
consent of any holder of Convertible Debentures, any supplemental indenture to
cure any ambiguities, defects or inconsistencies, comply with the Trust
Indenture Act and for certain other customary purposes.
 
INFORMATION CONCERNING THE DEBT TRUSTEE
 
  The Debt Trustee, prior to default, undertakes to perform only such duties
as are specifically set forth in the Indenture and, after default, shall
exercise the same degree of care as a prudent person would exercise in the
conduct of his or her own affairs. Subject to such provision, the Debt Trustee
is under no obligation to exercise any of the powers vested in it by the
Indenture at the request of any holder of Convertible Debentures, unless
offered reasonable indemnity by such holder against the costs, expenses and
liabilities which might be incurred thereby. The Debt Trustee is not required
to expend or risk its own funds or otherwise incur personal financial
liability in the performance of its duties if the Debt Trustee reasonably
believes that repayment or adequate indemnity is not reasonably assured to it.
 
  The Indenture also contains limitations on the right of the Debt Trustee, as
a creditor of McKesson, to obtain payment of claims in certain cases or to
realize on certain property received in respect of any such claim as security
or otherwise. In addition, the Debt Trustee may be deemed to have a
conflicting interest and may be required to resign as Debt Trustee if at the
time of a default under the Indenture it is a creditor of McKesson. The
Company may from time to time maintain deposit accounts and conduct its
banking transactions with the Debt Trustee in the ordinary course of business.
 
GOVERNING LAW
 
  The Indenture and the Convertible Debentures are governed by, and construed
in accordance with, the internal laws of the State of New York.
 
MISCELLANEOUS
 
  The Indenture provides that McKesson is to pay all fees and expenses related
to (i) the original offering of the Trust Securities and the Convertible
Debentures, (ii) the organization, maintenance and dissolution of the Trust,
(iii) the retention of the MFT Trustees and (iv) the enforcement by the
Institutional Trustee of the rights of the holders of the Convertible
Preferred Securities.
 
  McKesson will have the right at all times to assign any of its respective
rights or obligations under the Indenture to a direct or indirect wholly-owned
subsidiary of McKesson; provided that, in the event of any such assignment,
McKesson will remain liable for all of its obligations. Subject to the
foregoing, the Indenture is binding upon and inures to the benefit of the
parties thereto and their respective successors and assigns. The Indenture
provides that it may not otherwise be assigned by the parties thereto.
 
                                      45
<PAGE>
 
                        EFFECT OF OBLIGATIONS UNDER THE
                   CONVERTIBLE DEBENTURES AND THE GUARANTEE
 
  As set forth in the Declaration, the sole purpose of the Trust is to issue
the Trust Securities evidencing undivided beneficial interests in the assets
of the Trust, and to invest the proceeds from such issuance and sale in the
Convertible Debentures.
 
  As long as payments of interest and other payments are made when due on the
Convertible Debentures, such payments will be sufficient to cover
distributions and payments due on the Trust Securities because of the
following factors: (i) the aggregate principal amount of Convertible
Debentures is equal to the sum of the aggregate stated liquidation amount of
the Trust Securities; (ii) the interest rate and the interest and other
payment dates on the Convertible Debentures match the distribution rate and
distribution and other payment dates for the Convertible Preferred Securities;
(iii) McKesson shall pay all, and the Trust shall not be obligated to pay,
directly or indirectly, any costs, expenses, debt and obligations of the Trust
(other than with respect to the Trust Securities); and (iv) the Declaration
further provides that the MFT Trustees shall not take or cause or permit the
Trust to, among other things, engage in any activity that is not consistent
with the purposes of the Trust.
 
  Payments of distributions (to the extent funds therefor are available) and
other payments due on the Convertible Preferred Securities (to the extent
funds therefor are available) are guaranteed by McKesson as and to the extent
set forth under "Description of the Guarantee" herein. If McKesson does not
make interest payments on the Convertible Debentures purchased by the Trust,
it is expected that the Trust will not have sufficient funds to pay
distributions on the Convertible Preferred Securities. The Guarantee is a full
guarantee on a subordinated basis with respect to the Convertible Preferred
Securities issued by the Trust from the time of its issuance but does not
apply to any payment of distributions unless and until the Trust has
sufficient funds for the payment of such distributions. The Guarantee covers
the payment of distributions and other payments on the Convertible Preferred
Securities only if and to the extent that McKesson has made a payment of
interest or principal on the Convertible Debentures held by the Trust as its
sole asset. See "Risk Factors--Limitations of the Guarantee." The Guarantee,
when taken together with McKesson's obligations under the Convertible
Debentures, the Indenture and the Declaration, including its obligations to
pay costs, expenses, debts and liabilities of the Trust (other than with
respect to the Trust Securities), provides a full and unconditional guarantee
of amounts on the Convertible Preferred Securities.
 
  If McKesson fails to make interest or other payments on the Convertible
Debentures when due (taking account of any Extension Period), the Declaration
provides a mechanism whereby a holder of the Convertible Preferred Securities,
using the procedures described in "Description of the Convertible Preferred
Securities--Voting Rights," may direct the Institutional Trustee to enforce
its rights under the Convertible Debentures. If the Institutional Trustee
fails to enforce its rights under the Convertible Debentures, any holder of
Convertible Preferred Securities may directly institute a legal proceeding
against McKesson to enforce the Institutional Trustee's rights under the
Convertible Debentures without first instituting legal proceedings against the
Institutional Trustee or any other person or entity. Notwithstanding the
foregoing, if a Declaration Event of Default has occurred and is continuing
and such event is attributable to the failure of the Company to pay interest
or principal on the Convertible Debentures on the date such interest or
principal is otherwise payable (or in the case of redemption on the Redemption
Date), a holder of Convertible Preferred Securities may institute a Direct
Action for payment on or after the respective due dates specified in the
Convertible Debentures. In connection with such Direct Action, McKesson will
be subrogated to the rights of such holder of Convertible Preferred Securities
under the Declaration to the extent of any payment made by McKesson to such
holder of Convertible Preferred Securities in such Direct Action. McKesson,
under the Guarantee, acknowledges that the Guarantee Trustee shall enforce the
Guarantee on behalf of holders of the Convertible Preferred Securities. If
McKesson fails to make payments under the Guarantee, the Guarantee provides a
mechanism whereby the holders of the Convertible Preferred Securities may
direct the Guarantee Trustee to enforce its rights thereunder. Any holder of
Convertible Preferred Securities may institute a legal proceeding directly
against McKesson to enforce such holder's right to receive payment under the
Guarantee without first instituting a legal proceeding against the Trust, the
Guarantee Trustee or any other person or entity.
 
                                      46
<PAGE>
 
                         DESCRIPTION OF CAPITAL STOCK
 
  The description of the Company's capital stock and of certain provisions of
Delaware law do not purport to be complete and are subject to and qualified in
their entirety by reference to the Company's Restated Certificate of
Incorporation (the "Certificate") and Restated By-Laws (the "By-Laws") and
Delaware law, and, with respect to certain rights of holders of shares of
Common Stock, the Rights Agreement (as hereinafter defined). Copies of such
documents have been filed with the Commission.
 
  As of the date hereof, the capital stock of McKesson consists of 200,000,000
authorized shares of Common Stock and 100,000,000 authorized shares of
preferred stock.
 
COMMON STOCK
 
  As of March 31, 1997, there were 45,784,949 shares of Common Stock issued
and outstanding. The holders of outstanding shares of Common Stock are
entitled to receive dividends out of assets legally available therefor at such
times and in such amounts as the McKesson Board of Directors (the "Board") may
from time to time determine. The shares of Common Stock are neither redeemable
nor convertible, and the holders thereof have no preemptive or subscription
rights to purchase any securities of McKesson. Upon liquidation, dissolution
or winding up of McKesson, the holders of Common Stock are entitled to receive
the assets of McKesson, which are legally available for distribution, after
payment of all debts, other liabilities and any liquidation preferences of
outstanding preferred stock. Each outstanding share of Common Stock is
entitled to one vote on all matters submitted to a vote of stockholders. There
is no cumulative voting.
 
SERIES PREFERRED STOCK
 
  As of March 31, 1997, there were no shares of series preferred stock issued
and outstanding. The Board is authorized to issue series preferred stock in
classes or series and to fix the designations, preferences, qualifications,
limitations, or restrictions of any class or series with respect to the rate
and nature of dividends, the price and terms and conditions on which shares
may be redeemed, the amount payable in the event of voluntary or involuntary
liquidation, the terms and conditions for conversion or exchange into any
other class or series of the stock, voting rights and other terms.
 
ANTI-TAKEOVER EFFECTS OF PROVISIONS OF THE COMPANY'S RESTATED CERTIFICATE OF
INCORPORATION AND BYLAWS
 
  The Certificate and By-Laws of McKesson contain certain provisions that may
be deemed to have an anti-takeover effect and may delay, deter or prevent a
tender offer or takeover attempt that a stockholder might consider in its best
interest, including those attempts that might result in a premium over the
market price for the shares held by stockholders.
 
  Pursuant to the Certificate, the Board is divided into three classes serving
staggered three-year terms. Directors can be removed from office only for
cause and only by the affirmative vote of the holders of at least a majority
of the voting power of the then outstanding shares of any class or series of
capital stock of the Company entitled to vote generally in the election of
directors. Vacancies and newly created directorships on the Board may be
filled only by a majority of the remaining directors or by the plurality vote
of the stockholders.
 
  The Certificate also provides that any action required or permitted to be
taken by the holders of Common Stock may be effected only at an annual or
special meeting of such holders, and that stockholders may act in lieu of such
meetings only by unanimous written consent. The By-Laws provide that special
meetings of holders of Common Stock may be called only by the Chairman or the
President of the Company or the Board. Holders of Common Stock are not
permitted to call a special meeting or to require that the Board call a
special meeting of stockholders.
 
  The By-Laws establish an advance notice procedure for the nomination, other
than by or at the direction of the Board, of candidates for election as
directors as well as for other stockholder proposals to be considered at
 
                                      47
<PAGE>
 
annual meetings of stockholders. In general, notice of intent to nominate a
director or raise business at such meetings must be received by the Company
not less than 60 nor more than 90 days prior to the date of the annual meeting
and must contain certain specified information concerning the person to be
nominated or the matters to be brought before the meeting and concerning the
stockholder submitting the proposal.
 
  The Certificate also provides that certain provisions of the By-Laws may
only be amended by the affirmative vote of the holders of 75% of the shares of
the Company outstanding and entitled to vote. The Certificate also provides
that, in addition to any affirmative vote required by law, the affirmative
vote of holders of 80% of the voting stock of the Company and two-thirds of
the voting stock other than voting stock held by an interested stockholder
shall be necessary to approve certain business combinations proposed by an
interested stockholder.
 
  The foregoing summary is qualified in its entirety by the provisions of the
Certificate and By-Laws, copies of which have been filed with the Commission.
 
RIGHTS PLAN
 
  Pursuant to the Company's Rights Agreement (as defined below), the Board
declared a dividend distribution of one right (a "Right") for each outstanding
share of Common Stock to stockholders of record of the Company at November 1,
1994 (the "Record Date"). Each Right entitles the registered holder to
purchase from the Company a unit consisting of one one-hundredth of a share of
Series A Junior Participating Preferred Stock (the "Series A Preferred Stock")
at a purchase price of $100 per unit. The terms of the Rights are set forth in
a Rights Agreement between the Company and a Rights Agent (the "Rights
Agreement"), a copy of which is filed with the Commission. The following
summary outlines certain provisions of the Rights Agreement and is qualified
by reference to the full text of the form of the Rights Agreement.
 
  The Rights are attached to all Common Stock certificates representing shares
outstanding at the Record Date and shares issued between the Record Date and
the Distribution Date (as hereinafter defined), and no separate rights
certificates (the "Rights Certificates") have been distributed. The Rights
will separate from the Common Stock, separate Rights Certificates will be
issued and a distribution date (the "Distribution Date") will occur upon the
earlier to occur of (i) ten business days following the date of a public
announcement that there is an Acquiring Person (as defined below) (such date,
the "Stock Acquisition Date"), (ii) ten business days following commencement
of a tender or exchange offer that would result in the offeror beneficially
owning 15% or more of the Common Stock or (iii) ten business days after the
Board determines that the ownership of 10% or more of the Company's
outstanding Common Stock by a person is (A) intended to cause the Company to
repurchase the Common Stock beneficially owned by such person or (B) is
causing, or is reasonably likely to cause, a material adverse impact on the
Company.
 
  The term "Acquiring Person" means any person who, together with affiliates
and associates, acquires beneficial ownership of shares of Common Stock
representing 15% or more of the Common Stock, but shall not include the
Company, any subsidiary of the Company, any employee benefit plan of the
Company or of any Subsidiary of the Company, or any person or entity
organized, appointed or established by the Company for or pursuant to the
terms of such plan.
 
  In the event that a person becomes an Acquiring Person (except pursuant to
an offer for all outstanding shares of Common Stock which the independent
directors determine to be fair to and otherwise in the best interests of the
Company and its stockholders), each holder of a Right will thereafter have the
right to receive, upon exercise, Common Stock (or, in certain circumstances,
cash, property or other securities of the Company) having a calculated value
equal to two times the exercise price of the Right. Notwithstanding the
foregoing, following the occurrence of such event, all Rights that are, or
(under certain circumstances specified in the Rights Agreement) were,
beneficially owned by an Acquiring Person and certain related persons and
transferees will be null and void. However, Rights are not exercisable
following the occurrence of such event until such time as the Rights are no
longer redeemable as set forth below.
 
                                      48
<PAGE>
 
  The Rights expire on September 14, 2004, unless redeemed earlier by the
Board.
 
  At any time prior to the tenth day following the Stock Acquisition Date, the
Company may redeem the Rights, in whole, but not in part, at a price of $.01
per Right.
 
  Until a Right is exercised, the holder thereof, as such, will have no rights
as a stockholder of the Company, including without limitation, the right to
vote or to receive dividends.
 
  In general, the Rights Agreement may be amended by the Board (i) prior to
the Distribution Date in any manner, and (ii) on or after the Distribution
Date in certain respects including (a) to shorten or lengthen any time period
and (b) in a manner not adverse to the interests of Rights holders. However,
amendments extending the redemption period must be made while the Rights are
still redeemable.
 
  The Rights have certain anti-takeover effects and will cause substantial
dilution to a person or group that attempts to acquire the Company on terms
not approved by the Board. The Rights should not interfere with any merger or
other business combination approved by the Board, since the Board may redeem
the Rights as provided above.
 
SECTION 203 OF DELAWARE GENERAL CORPORATION LAW
 
  The Company is subject to the "business combination" statute of the Delaware
General Corporation Law (Section 203). In general, such statute prohibits a
publicly held Delaware corporation from engaging in a "business combination"
with any "interested stockholder" for a period of three years after the date
of the transaction in which the person became an "interested stockholder,"
unless (i) such transaction is approved by the board of directors prior to the
date the interested stockholder obtains such status, (ii) upon consummation of
such transaction, the "interested stockholder" beneficially owned at least 85%
of the voting stock of the corporation outstanding at the time the transaction
commenced, excluding for purposes of determining the number of shares
outstanding those shares owned by (a) persons who are directors and also
officers and (b) employee stock plans in which employee participants do not
have the right to determine confidentially whether shares held subject to the
plan will be tendered in a tender or exchange offer, or (iii) the "business
combination" is approved by the board of directors and authorized at an annual
or special meeting of stockholders by the affirmative vote of at least 66 2/3%
of the outstanding voting stock which is not owned by the "interested
stockholder." A "business combination" includes mergers, asset sales and other
transactions resulting in financial benefit to the "interested stockholder."
An "interested stockholder" is a person who, together with affiliates and
associates, owns (or within three years, did own) beneficially 15% or more of
a corporation's voting stock. The statute could prohibit or delay mergers or
other takeover or change in control attempts with respect to the Company and,
accordingly, may discourage attempts to acquire the Company.
 
CERTAIN EFFECTS OF AUTHORIZED BUT UNISSUED STOCK
 
  The Company's authorized but unissued shares of Common Stock and series
preferred stock may be issued without additional stockholder approval and may
be utilized for a variety of corporate purposes, including future offerings to
raise additional capital or to facilitate corporate acquisitions.
 
  The issuance of series preferred stock could have the effect of delaying or
preventing a change in control of the Company. The issuance of preferred stock
could decrease the amount of earnings and assets available for distribution to
the holders of Common Stock or could adversely affect the rights and powers,
including voting rights, of the holders of the Common Stock. In certain
circumstances, such issuance could have the effect of decreasing the market
price of the Common Stock.
 
  One of the effects of the existence of unissued and unreserved Common Stock
or series preferred stock may be to enable the Board to issue shares to
persons friendly to current management which could render more difficult or
discourage an attempt to obtain control of the Company by means of a merger,
tender offer, proxy
 
                                      49
<PAGE>
 
contest or otherwise, and thereby protect the continuity of management. Such
additional shares also could be used to dilute the stock ownership of persons
seeking to obtain control of the Company.
 
  The Company plans to issue additional shares of Common Stock (i) upon the
exercise of options which have been granted or which may be granted in the
future to directors, officers and employees of the Company and (ii) upon
conversion of the Trust Securities. The Company does not currently have any
plans to issue shares of preferred stock, although, 10,000,000 shares of
Series A Preferred Stock have been designated pursuant to the Company's Rights
Plan. See "--Rights Plan."
 
LIMITATION OF DIRECTORS LIABILITY
 
  The Certificate contains a provision that limits the liability of McKesson's
directors for monetary damages for breach of fiduciary duty as a director to
the fullest extent permitted by the Delaware General Corporation Law. Such
limitation does not, however, affect the liability of a director (i) for any
breach of the director's duty of loyalty to the Company or its stockholders,
(ii) for acts or omissions not in good faith or that involve intentional
misconduct or a knowing violation of law, (iii) in respect of certain unlawful
dividend payments or stock redemptions or purchases and (iv) for any
transaction from which the director derives an improper personal benefit. The
effect of this provision is to eliminate the rights of the Company and its
stockholders (through stockholders' derivative suits on behalf of the Company)
to recover monetary damages against a director for breach of the fiduciary
duty of care as a director (including breaches resulting from negligent or
grossly negligent behavior) except in the situations described in clauses (i)
through (iv) above. This provision does not limit or eliminate the rights of
the Company or any stockholder to seek non-monetary relief such as an
injunction or rescission in the event of a breach of a director's duty of
care. In addition, the directors and officers of the Company have
indemnification protection.
 
                                      50
<PAGE>
 
                     UNITED STATES FEDERAL INCOME TAXATION
 
GENERAL
 
  The following is a summary of certain United States federal income tax
consequences of the purchase, ownership and disposition of the Convertible
Preferred Securities. Unless otherwise stated, this summary only deals with
Convertible Preferred Securities held as capital assets (generally, assets
held for investment). The tax treatment of a holder of Convertible Preferred
Securities may vary depending on his particular situation. This summary does
not address all of the tax consequences that may be relevant to holders who
may be subject to special tax treatment such as, for example, insurance
companies, broker-dealers, tax-exempt organizations, or, except to the extent
described below, foreign taxpayers. In addition, this summary does not address
any aspects of state, local, or foreign tax laws. This summary is based on the
United States federal income tax law in effect as of the date hereof, which is
subject to change, possibly on a retroactive basis. Each investor is urged to
consult his tax advisor as to the particular tax consequences of purchasing,
owning, and disposing of the Convertible Preferred Securities, including the
application and effect of United States federal, state, local, foreign, and
other tax laws.
 
CLASSIFICATION OF THE CONVERTIBLE DEBENTURES
 
  In connection with the issuance of the Convertible Debentures, Skadden,
Arps, Slate, Meagher & Flom LLP, special tax counsel to the Company and the
Trust ("Tax Counsel"), will render an opinion generally to the effect that
under current law and assuming full compliance with the terms of the Indenture
and certain other documents, and based on certain facts and assumptions
contained in such opinion, the Convertible Debentures to be held by the Trust
will be classified, for United States federal income tax purposes, as
indebtedness of the Company.
 
CLASSIFICATION OF THE TRUST
 
  In connection with the issuance of the Convertible Preferred Securities, Tax
Counsel will render an opinion generally to the effect that, under current law
and assuming full compliance with the terms of the Declaration, the Indenture,
and certain other documents, and based on certain facts and assumptions
contained in such opinion, the Trust will be classified for United States
federal income tax purposes, as a grantor trust and not as an association
taxable as a corporation. Accordingly, for United States federal income tax
purposes, each holder of Convertible Preferred Securities will generally be
treated as the owner of an undivided interest in the Convertible Debentures,
and as further discussed below, each holder will be required to include in
ordinary income his allocable share of interest (or OID, if any) paid or
accrued on the Convertible Debentures.
 
POTENTIAL EXTENSION OF INTEREST PAYMENT PERIOD AND ORIGINAL ISSUE DISCOUNT
 
  Under recently issued Treasury regulations (the "Regulations"), a debt
instrument will be deemed to be issued with OID if there is more that a
"remote" contingency that periodic stated interest payments due on the
instrument will not be timely paid. Because the exercise by the Company of its
option to defer the payment of stated interest on the Convertible Debentures
would prevent the Company from declaring dividends on any class of equity, the
Company believes that the likelihood of its exercising the option is "remote"
within the meaning of the Regulations. As a result, the Company intends to
take the position, based on the advice of Tax Counsel, that the Convertible
Debentures will not be deemed to be issued with OID. Accordingly, based on
this position, stated interest payments on the Convertible Debentures will be
includible in the ordinary income of a holder at the time that such payments
are paid or accrued in accordance with the holder's regular method of
accounting. Because the Regulations have not yet been addressed in any
published rulings or other published interpretations issued by the Internal
Revenue Service, it is possible that the Internal Revenue Service could take a
position contrary the position taken by the Company.
 
  Exercise of Deferral Option. If the Company were to exercise its option to
defer the payment of stated interest on the Convertible Debentures, the
Convertible Debentures would be treated, solely for purpose of the
 
                                      51
<PAGE>
 
OID rules, as being "re-issued" at such time with OID. Under these rules, a
holder of the Convertible Debentures would be required to include OID in
ordinary income, on a current basis, over the period that the instrument is
held even though the Company would not be making any actual cash payments
during the extended interest payment period. The amount of interest income
includible in the taxable income of a holder of the Convertible Debentures
would be determined on the basis of a constant yield method over the remaining
term of the instrument and the actual receipt of future payments of stated
interest on the Convertible Debentures would no longer be separately reported
as taxable income. The amount of OID that would accrue, in the aggregate,
during the extended interest payment period would be approximately equal to
the amount of the cash payment due at the end of such period. Any OID included
in income would increase the holder's adjusted tax basis in the Convertible
Debentures and the holder's actual receipt of interest payments would reduce
such basis.
 
  Because income on the Convertible Preferred Securities will constitute
interest income for United States Federal income tax purposes, corporate
holders of Convertible Preferred Securities will not be entitled to claim a
dividends received deduction in respect of such income.
 
MARKET DISCOUNT AND BOND PREMIUM
 
  To the extent a holder acquires Convertible Preferred Securities at a price
that is greater or less than the adjusted issue price (which should generally
approximate the face amount plus accrued but unpaid interest on the
Convertible Debentures) of such holder's proportionate share of the
Convertible Debentures, the holder may be deemed to have acquired its
undivided interest in the Convertible Debentures with acquisition premium or
market discount.
 
  A holder who acquires an undivided beneficial interest in the Convertible
Debentures at a market discount will generally be required to recognize
ordinary income to the extent of accrued market discount on the Convertible
Debentures upon their retirement or, to the extent of any gain, upon the
disposition of the Convertible Preferred Securities. Such market discount will
accrue ratably or, at the election of the holder, under a constant yield
method over the remaining term of the Convertible Debentures. A holder will
also be required to defer the deduction of a portion of the interest paid or
accrued on indebtedness incurred to purchase or carry Convertible Preferred
Securities that represent an undivided interest in Convertible Debentures
acquired with market discount. In lieu of the foregoing, a holder may elect to
include market discount in income currently as it accrues on all market
discount instruments acquired by such holder in the taxable year of the
election or thereafter, in which case the interest deferral rule will not
apply. A holder will not recognize income for any accrued market discount
attributable to Convertible Preferred Securities surrendered for conversion
into McKesson Common Stock. Upon disposition of the McKesson Common Stock
received however, any gain will be treated as ordinary income to the extent of
such accrued market discount.
 
  A holder who acquires an undivided beneficial interest in the Convertible
Debentures at a premium will be able to offset the amount of such holder's
amortizable bond premium attributable to that taxable year against such
holder's allocable share of interest (or OID, if any) paid or accrued on the
Convertible Debentures.
 
  Holders are advised to consult their tax advisors regarding the market
discount and acquisition premium rules.
 
RECEIPT OF CONVERTIBLE DEBENTURES OR CASH UPON LIQUIDATION OF THE TRUST
 
  If Company exercises its right to liquidate the Trust and cause the
Convertible Debentures to be distributed on a pro rata basis to the holders of
the Convertible Preferred Securities, such distribution would be treated as a
nontaxable event to the holders. In such event, each holder of Convertible
Preferred Securities would have an adjusted tax basis in the Convertible
Debentures received in the liquidation equal to the adjusted tax basis in his
Convertible Preferred Securities surrendered therefor and the holding period
of the Convertible Debentures would include the period during which the holder
had held the Convertible Preferred Securities. If, however, the Trust is
characterized, for United States Federal income tax purposes, as an
association taxable as a corporation
 
                                      52
<PAGE>
 
at the time of such liquidation, the distribution of the Convertible
Debentures would constitute a taxable event to the holders of Convertible
Preferred Securities.
 
  If the Convertible Debentures are redeemed for cash and the proceeds of such
redemption are distributed to holders in redemption of their Convertible
Preferred Securities, the redemption would be treated as a sale of the
Convertible Preferred Securities, in which gain or loss would be recognized,
as described immediately below.
 
SALE OF CONVERTIBLE PREFERRED SECURITIES
 
  Upon the sale of the Convertible Preferred Securities, a holder will
recognize gain or loss in an amount equal to the difference between his
adjusted tax basis in the Convertible Preferred Securities and the amount
realized in the sale (except to the extent of any amount received in respect
of accrued but unpaid interest not previously included in income). Subject to
the market discount rules described above, such gain or loss will be a capital
gain or loss and will be a long term capital gain or loss if the Convertible
Preferred Securities have been held for more than one year.
 
  The Convertible Preferred Securities may trade at a price that does not
accurately reflect the value of accrued but unpaid interest (or OID if the
Convertible Debentures are treated as having been issued, or reissued, with
OID) with respect to the underlying Convertible Debentures. A holder who
disposes of his Convertible Preferred Securities will be required to include
in ordinary income (i) any portion of the amount realized that is attributable
to such accrued but unpaid interest to the extent not previously included in
income or (ii) any amount of OID, in either case, that has accrued on his pro
rata share of the underlying Convertible Debentures during the taxable year of
sale through the date of disposition. Any such income inclusion will increase
the holder's adjusted tax basis in his Convertible Preferred Securities
disposed of. To the extent that the amount realized in the sale is less than
the holder's adjusted tax basis, a holder will recognize a capital loss.
Subject to certain limited exceptions, capital losses cannot be applied to
offset ordinary income for United States Federal income tax purposes.
 
CONVERSION OF CONVERTIBLE PREFERRED SECURITIES INTO MCKESSON COMMON STOCK
 
  Except possibly to the extent attributable to accrued and unpaid interest
(including OID, if any) on the Convertible Debentures, a holder of Convertible
Preferred Securities will not recognize income, gain or loss upon the
conversion of the Convertible Preferred Securities into McKesson Common Stock
through the Conversion Agent. A holder of Convertible Preferred Securities
will, however, recognize gain upon the receipt of cash in lieu of a fractional
share of McKesson Common Stock equal to the amount of cash received less such
holder's tax basis in such fractional share. Such a holder's tax basis in the
McKesson Common Stock received upon conversion should generally be equal to
such holder's tax basis in the Convertible Preferred Securities delivered to
the Conversion Agent for exchange less the basis allocated to any fractional
share for which cash is received and such holder's holding period in the
McKesson Common Stock received upon conversion should generally begin on the
date such holder acquired the Convertible Preferred Securities delivered to
the Conversion Agent for exchange.
 
ADJUSTMENT OF CONVERSION PRICE
 
  If at any time the Company makes a distribution of property to stockholders
that would be taxable to such stockholders as a dividend for United States
federal income tax purposes and, in accordance with the antidilution
provisions of the Convertible Preferred Securities, the Conversion Price of
the Convertible Preferred Securities is decreased, the amount of such decrease
may be deemed to be the payment of a taxable dividend to holders of the
Convertible Preferred Securities. For example, a decrease in the Conversion
Price in the event of distributions of evidences of indebtedness or assets of
the Company will generally result in deemed dividend treatment to holders of
the Convertible Preferred Securities, but generally a decrease in the event of
stock dividends or the distribution of rights to subscribe for McKesson Common
Stock will not. See "Description of the Convertible Preferred Securities--
Conversion Rights."
 
                                      53
<PAGE>
 
PROPOSED TAX LEGISLATION
 
  On February 6, 1997, as part of President Clinton's Fiscal 1998 Budget
Proposal, the United States Treasury Department proposed legislation that
would, among other things, deny an issuer a deduction for United States
federal income tax purposes for the payment of interest on instruments with
characteristics similar to the Convertible Debentures. If the proposed
legislation were enacted in its current form, it is not expected to apply to
the Convertible Debentures since the proposed effective date for this
provision is the date of first Congressional committee action. There can be no
assurances, however, that the proposed legislation, if enacted, or similar
legislation enacted after the date hereof, would not adversely affect the tax
treatment of the Convertible Debentures, resulting in a Tax Event which would
allow the Company to redeem the Convertible Preferred Securities. See
"Description of the Convertible Preferred Securities--Special Event
Distribution; Tax Redemption."
 
NON-U.S. HOLDERS
 
  For purposes of this discussion, a "Non-U.S. Holder" is any corporation,
individual, partnership, estate or trust that is, as to the United States, a
foreign corporation, a nonresident alien individual, a foreign partnership, or
a nonresident fiduciary of a foreign estate or trust.
 
  Payments made to a holder of Convertible Preferred Securities who is a Non-
U.S. Holder will not be subject to withholding of United States federal income
tax, provided that (a) the beneficial owner of the Convertible Preferred
Securities does not actually or constructively own 10% or more of the total
combined voting power of all classes of stock of the Company entitled to vote,
(b) the beneficial owner of the Convertible Preferred Securities is not a
controlled foreign corporation that is related to the Company through stock
ownership, and (c) either (A) the beneficial owner of the Convertible
Preferred Securities certifies to the Trust or its agent, under the penalty of
perjury, that it is not a United States holder and provides his name and
address or (B) a securities clearing organization, bank or other financial
institution that holds customers' securities in the ordinary course of its
trade or business (a "Financial Institution"), and holds the Convertible
Preferred Securities in such capacity, certifies to the Trust or its agent,
under the penalty of perjury, that such statement has been received from the
beneficial owner by it or by a Financial Institution between it and the
beneficial owner and furnishes the Trust or its agent with a copy thereof. In
addition, a Non-U.S. Holder of Convertible Preferred Securities will not be
subject to withholding of United States federal income tax on any gain
realized upon the sale or other disposition of a Preferred Security.
 
  If the Convertible Preferred Securities are converted into McKesson Common
Stock, any dividends paid to a Non-U.S. Holder will be subject to withholding
of United States Federal income tax at a 30% rate or such lower rate as may be
specified by an applicable income tax treaty unless the dividend is
effectively connected with the conduct of a trade or business of a Non-U.S.
Holder with the U.S.
 
INFORMATION REPORTING
 
  Generally, income on the Convertible Preferred Securities will be reported
to holders on Forms 1099, which forms should be mailed to holders of
Convertible Preferred Securities by January 31 following each calendar year.
 
                                      54
<PAGE>
 
                             ERISA CONSIDERATIONS
 
  The Employee Retirement Income Security Act of 1974, as amended ("ERISA"),
and the United States Internal Revenue Code of 1986, as amended (the "Code"),
impose certain restrictions on (a) employee benefit plans (as defined in
Section 3(3) of ERISA), (b) plans described in section 4975(e)(1) of the Code,
including individual retirement accounts or Keogh plans, (c) any entities
whose underlying assets include plan assets by reason of a plan's investment
in such entities (each a "Plan") and (d) persons who have certain specified
relationships to such Plans ("Parties-in-Interest" under ERISA and
"Disqualified Persons" under the Code). Moreover, based on the reasoning of
the United States Supreme Court in John Hancock Life Ins. Co. v. Harris Trust
and Sav. Bank, 114 S. Ct. 517 (1993), an insurance company's general account
may be deemed to include assets of the Plans investing in the general account
(e.g., through the purchase of an annuity contract), and the insurance company
might be treated as a Party-in-Interest with respect to a Plan by virtue of
such investment. ERISA also imposes certain duties on persons who are
fiduciaries of Plans subject to ERISA and prohibits certain transactions
between a Plan and Parties-in-Interest or Disqualified Persons with respect to
such Plans.
 
  The Department of Labor ("DOL") has issued a regulation (29 C.F.R.
(S) 2510.3-101) concerning the definition of what constitutes the assets of a
Plan (the "Plan Assets Regulation"). This regulation provides that, as a
general rule, the underlying assets and properties of corporations,
partnerships, trusts and certain other entities in which a Plan purchases an
"equity interest" will be deemed for purposes of ERISA to be assets of the
investing Plan unless certain exceptions apply.
 
  The Plan Assets Regulation defines an "equity interest" as any interest in
an entity other than an instrument that is treated as indebtedness under
applicable local law and which has no substantial equity features. It is
likely that the Convertible Preferred Securities would be treated as "equity
interests" for purposes of the Plan Assets Regulation. In addition, there can
be no assurance that any of the exceptions set forth in the Plan Assets
Regulation will apply to the purchase of the Convertible Preferred Securities.
Information regarding the potential applicability of any such exceptions will
be provided in the Prospectus Supplement.
 
  Under the terms of the Plan Assets Regulation, if the Trust were deemed to
hold Plan assets by reason of a Plan's investment in the Convertible Preferred
Securities, such Plan assets would include an undivided interest in the assets
held by the Trust, including the Convertible Debentures. In such event, any
party exercising authority or control regarding the management or disposition
of the Convertible Debentures may be deemed to be a Plan "fiduciary," and thus
subject to the fiduciary requirements and prohibited transaction provisions of
ERISA and the Code. Furthermore, inasmuch as the Trustee may become a
fiduciary with respect to the ERISA Plans that purchase the Convertible
Preferred Securities, there may be an improper delegation by such ERISA Plans
of the responsibility to manage Plan assets.
 
  In addition, if McKesson or any affiliate is a Party-in-Interest or
Disqualified Person with respect to an investing Plan, such Plan's investment
could be deemed to constitute a transaction prohibited under Title I of ERISA
or Section 4975 of the Code (e.g., the extension of credit between a Plan and
a Party-in-Interest or Disqualified Person). Such transactions may, however,
be subject to one or more statutory or administrative exemptions such as
Prohibited Transaction Class Exemption ("PTCE") 90-1, which exempts certain
transactions involving insurance company pooled separate accounts; PTCE 95-60,
which exempts certain transactions involving insurance company general
accounts; PTCE 91-38, which exempts certain transactions involving bank
collective investment funds; PTCE 84-14, which exempts certain transactions
effected on behalf of a Plan by a "qualified professional asset manager"; and
PTCE 96-23, which exempts certain transactions effected on behalf of a Plan by
an "in-house asset manager"; or pursuant to any other available exemption.
Such exemptions may not, however, apply to all of the transactions that could
be deemed prohibited transactions in connection with the Convertible Preferred
Securities.
 
  Each purchaser of the Convertible Preferred Securities will be deemed to
have represented and agreed that either (i) it is not purchasing the
Convertible Preferred Securities with the assets of any Plan or (ii) one or
more exemptions from the prohibited transaction rules of ERISA and the Code
applies to such purchase, such that the
 
                                      55
<PAGE>
 
use of such assets to acquire and hold the Convertible Preferred Securities
does not and will not constitute a non-exempt prohibited transaction for
purposes of Section 406 of ERISA and Section 4975 of the Code.
 
  Any purchaser that is an insurance company using the assets of an insurance
company general account should note that the Small Business Job Protection Act
of 1996 added new Section 401(c) of ERISA relating to the status of the assets
of insurance company general accounts under ERISA and Section 4975 of the
Code. Pursuant to Section 401(c), the Department of Labor is required to issue
final regulations (the "General Account Regulations") not later than December
31, 1997 with respect to insurance policies issued on or before December 31,
1998 that are supported by an insurer's general account. The General Account
Regulations are to provide guidance on which assets held by the insurer
constitute "plan assets" for purposes of the fiduciary responsibility
provisions of ERISA and Section 4975 of the Code. Section 401(c) also provides
that, except in the case of avoidance of the General Account Regulation and
actions brought by the Secretary of Labor relating to certain breaches of
fiduciary duties that also constitute breaches of state or federal criminal
law, until the date that is 18 months after the General Account Regulations
become final, no liability under the fiduciary responsibility and prohibited
transaction provisions of ERISA and Section 4975 may result on the basis of a
claim that the assets of the general account of an insurance company
constitute the plan assets of any such plan. The plan asset status of
insurance company separate accounts is unaffected by new Section 401(c) of
ERISA, and separate account assets continue to be treated as the assets of any
Plan invested in a separate account.
 
  Any Plan fiduciary that proposes to cause a Plan to purchase Convertible
Preferred Securities should consult with its counsel as to the potential
applicability of ERISA and the Code to such investment and whether any
exemption from the prohibited transaction rules would be applicable and
determine on its own whether all conditions of such exemption or exemptions
are satisfied. Moreover, each Plan fiduciary should take into account, among
other considerations, whether the fiduciary has the authority to make the
investment; the composition of the Plan's portfolio with respect to
diversification by type of asset; the Plan's funding objectives; the tax
effects of the investment; and whether under the general fiduciary standards
of investment prudence and diversification an investment in the Convertible
Preferred Securities is appropriate for the Plan, taking into account the
overall investment policy of the Plan and the composition of the Plan's
investment portfolio.
 
                                SELLING HOLDERS
 
  The Convertible Preferred Securities were originally issued by the Trust and
sold by Morgan Stanley & Co. Incorporated (the "Initial Purchaser"), in a
transaction exempt from the registration requirements of the Securities Act,
to persons reasonably believed by such Initial Purchaser to be "qualified
institutional buyers" (as defined in Rule 144A under the Securities Act), to
certain qualified institutional buyers acting on behalf of institutional
"accredited investors" (as defined in Rule 501(a)(1), (2), (3) or (7) under
the Securities Act), or outside the United States to non-U.S. persons in
offshore transactions in reliance on Regulation S under the Securities Act.
The Selling Holders may from time to time offer and sell pursuant to this
Prospectus any or all of the Convertible Preferred Securities, any Convertible
Debentures and McKesson Common Stock issued upon conversion of the Preferred
Securities. The term Selling Holder includes the record holders and the
beneficial owners of the Convertible Preferred Securities and their
transferees, pledgees, donees or other successors.
 
  The following table sets forth information with respect to the record
holders of the Convertible Preferred Securities as of April 7, 1997.
 
<TABLE>
<CAPTION>
                                                                      NUMBER OF
                                                                     CONVERTIBLE
                                                                      PREFERRED
                             SELLING HOLDER                          SECURITIES
                             --------------                          -----------
     <S>                                                             <C>
     1.CEDE & CO....................................................  3,981,000
     2.SALKELD & CO.................................................     13,400
     3.MORGAN STANLEY & CO. INCORPORATED............................      5,600
                                                                      ---------
       Total........................................................  4,000,000
                                                                      =========
</TABLE>
 
 
                                      56
<PAGE>
 
Because the Selling Holders may, pursuant to this Prospectus, offer all or
some portion of the Convertible Preferred Securities, the Convertible
Debentures or the McKesson Common Stock issuable upon conversion of the
Convertible Preferred Securities, no estimate can be given as to the amount of
the Convertible Preferred Securities, the Convertible Debentures or the
McKesson Common Stock issuable upon conversion of the Convertible Preferred
Securities that will be held by the Selling Holders upon termination of any
such sales. In addition, the Selling Holders identified above may have sold,
transferred or otherwise disposed of all or a portion of their Convertible
Preferred Securities since the date on which they provided the information
regarding their Convertible Preferred Securities, in transactions exempt from
the registration requirements of the Securities Act.
 
                             PLAN OF DISTRIBUTION
 
  The Selling Holders may offer the Offered Securities from time to time
following effectiveness of the Registration Statement of which this Prospectus
constitutes a part. The Selling Holders may sell the Offered Securities (i) to
or through underwriters, brokers or dealers; (ii) directly to one or more
other purchasers; (iii) through agents on a best-efforts basis or otherwise;
or (iv) through a combination of any such methods of sale. The Offered
Securities may be sold from time to time in one or more transactions at a
fixed price or prices, which may be changed, or at market prices prevailing at
the time of sale, at prices related to such prevailing market prices, or at
negotiated prices. The Selling Holders and any underwriters, broker-dealers or
agents that participate in the distribution of Offered Securities may be
deemed to be "underwriters" within the meaning of the Securities Act and any
profit on the sale of such securities and any discounts, commissions,
concessions or other compensation received by any such underwriter, broker-
dealer or agent may be deemed to be underwriting discounts and commissions
under the Securities Act. At the time a particular offering of the Offered
Securities is made, a Prospectus Supplement, if required, will be distributed
which will set forth the aggregate amount and type of Offered Securities being
offered and the terms of the offering, including the name or names of any
underwriters, broker-dealers or agents, any discounts, commissions and other
terms constituting compensation from the Selling Holders and any discounts,
commissions or concessions allowed or reallowed or paid to broker-dealers.
 
  To comply with the securities laws of certain jurisdictions, if applicable,
the Offered Securities will be offered or sold in such jurisdictions only
through registered or licensed brokers or dealers. In addition, in certain
jurisdictions the Offered Securities may not be offered or sold unless they
have been registered or qualified for sale in such jurisdictions or any
exemption from registration or qualification is available and is complied
with.
 
  In order to facilitate the offering of the Offered Securities, the
underwriters, if any, may engage in transactions that stabilize, maintain or
otherwise affect the price of the Offered Securities. Specifically, the
underwriters, if any, may overallot in connection with the offering, creating
a short position in the Offered Securities for their own account. In addition,
to cover overallotments or to stabilize the price of the Offered Securities,
the underwriters, if any, may bid for, and purchase, the Offered Securities in
the open market. Finally, the underwriting syndicate, if any, may reclaim
selling concessions allowed to an underwriter or a dealer for distributing the
Offered Securities in the offering, if the syndicate repurchases previously
distributed Offered Securities in transactions to cover syndicate short
positions, in stabilization transactions or otherwise. Any of these activities
may stabilize or maintain the market price of the Offered Securities above
independent market levels. The underwriters, if any, are not required to
engage in these activities, and may end any of these activities at any time.
 
  Pursuant to the Registration Rights Agreement, all expenses of the
registration of the Offered Securities will be paid by the Company, including,
without limitation, Commission filing fees and expenses of compliance with
state securities or "blue sky" laws; provided, however, that the Selling
Holders will pay all underwriting discounts and selling commissions, if any.
The Selling Holders will be indemnified by the Company and the Trust, jointly
and severally, against certain civil liabilities, including certain
liabilities under the Securities Act, or will be entitled to contribution in
connection therewith. The Company and the Trust will be indemnified by the
Selling Holders severally against certain civil liabilities, including certain
liabilities under the Securities Act, or will be entitled to contribution in
connection therewith.
 
                                      57
<PAGE>
 
                                    EXPERTS
 
  The consolidated financial statements of McKesson and the related financial
statement schedule incorporated in this Prospectus by reference from the
Company's Annual Report on Form 10-K/A for the year ended March 31, 1996 and
the consolidated financial statements of FoxMeyer Corporation for the year
ended March 31, 1996 incorporated in this Prospectus by reference from the
Company's Current Report on Form 8-K/A filed with the Commission on April 28,
1997 have been audited by Deloitte & Touche LLP, independent auditors, as
stated in their reports incorporated herein by reference (which report dated
May 13, 1996 (December 31, 1996 as to Notes 8 and 17) on the Company's
consolidated financial statements expresses an unqualified opinion and
includes an explanatory paragraph relating to a change in the Company's method
of accounting for post employment benefits to conform with Statement of
Financial Accounting Standards No. 112 and report on FoxMeyer Corporation's
consolidated financial statements dated June 28, 1996 (March 18, 1997 as to
paragraph seven of Note Q), which report expresses an unqualified opinion and
includes an explanatory paragraph relating to the sale of the principal assets
of FoxMeyer Corporation and its Chapter 7 bankruptcy filing. Such consolidated
financial statements and financial statement schedule have been so
incorporated in reliance upon the reports of such firm given upon their
authority as experts in accounting and auditing.
 
                                 LEGAL MATTERS
 
  Certain legal matters with respect to the Convertible Preferred Securities,
the Convertible Debentures and the Guarantee being offered hereby and the
Common Stock issuable upon conversion of the Convertible Debentures and
certain United States federal income taxation matters have been passed upon
for McKesson and the Trust by Skadden, Arps, Slate, Meagher & Flom LLP.
 
                                      58
<PAGE>
 
- - -------------------------------------------------------------------------------
- - -------------------------------------------------------------------------------
 
  NO PERSON IS AUTHORIZED TO GIVE ANY INFORMATION OR TO MAKE ANY
REPRESENTATIONS OTHER THAN THOSE CONTAINED IN THIS PROSPECTUS IN CONNECTION
WITH THE OFFERING MADE BY THIS PROSPECTUS. IF GIVEN OR MADE, SUCH INFORMATION
OR REPRESENTATIONS MUST NOT BE RELIED UPON AS HAVING BEEN AUTHORIZED BY
MCKESSON FINANCING TRUST, MCKESSON CORPORATION, THE SELLING HOLDERS OR ANY OF
THEIR AGENTS. THIS PROSPECTUS DOES NOT CONSTITUTE AN OFFER TO SELL, OR A
SOLICITATION OF AN OFFER TO BUY, ANY OF THE SECURITIES OFFERED HEREBY IN ANY
JURISDICTION WHERE, OR TO ANY PERSON TO WHOM, IT IS UNLAWFUL TO MAKE SUCH
OFFER OR SOLICITATION. NEITHER THE DELIVERY OF THIS PROSPECTUS NOR ANY SALE
MADE HEREUNDER SHALL, UNDER ANY CIRCUMSTANCES, CREATE AN IMPLICATION THAT
THERE HAS NOT BEEN ANY CHANGE IN THE FACTS SET FORTH IN THIS PROSPECTUS OR IN
THE AFFAIRS OF MCKESSON FINANCING TRUST OR MCKESSON CORPORATION SINCE THE DATE
HEREOF.
 
                               ----------------
 
                               TABLE OF CONTENTS
 
<TABLE>
<CAPTION>
                                                                            PAGE
                                                                            ----
<S>                                                                         <C>
Available Information......................................................   4
Incorporation of Certain Documents by Reference............................   5
Special Note Regarding Forward-Looking Statements                             5
Risk Factors...............................................................   6
The Company................................................................  10
Use of Proceeds............................................................  13
Accounting Treatment.......................................................  13
Ratio of Earnings to Fixed Charges.........................................  13
McKesson Financing Trust...................................................  14
Description of the Convertible Preferred Securities........................  15
Description of the Guarantee...............................................  33
Description of the Convertible Debentures..................................  36
Effect of Obligations Under the Convertible Debentures and the Guarantee...  46
Description of Capital Stock...............................................  47
United States Federal Income Taxation......................................  51
ERISA Considerations.......................................................  55
Selling Holders............................................................  56
Plan of Distribution.......................................................  57
Experts....................................................................  58
Legal Matters..............................................................  58
</TABLE>
 
- - -------------------------------------------------------------------------------
- - -------------------------------------------------------------------------------
- - -------------------------------------------------------------------------------
- - -------------------------------------------------------------------------------
 
                             4,000,000 CONVERTIBLE
                             PREFERRED SECURITIES
 
                                   MCKESSON
                                FINANCING TRUST
 
                             5% TRUST CONVERTIBLE
                             PREFERRED SECURITIES
                           GUARANTEED TO THE EXTENT
                             SET FORTH HEREIN BY,
 
                                   MCKESSON
                                  CORPORATION
 
                               ----------------
                                  PROSPECTUS
                               ----------------
 
- - -------------------------------------------------------------------------------
- - -------------------------------------------------------------------------------
<PAGE>
 
                                    PART II
 
                    INFORMATION NOT REQUIRED IN PROSPECTUS
 
ITEM 14. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION.
 
  The following expenses (other than the SEC filing fee) are estimated.
 
<TABLE>
      <S>                                                           <C>
      SEC registration fee......................................... $ 68,181.82
      Printing and engraving expenses..............................   55,000.00
      Legal fees and expenses......................................   30,000.00
      Accounting fees and expenses.................................   10,000.00
      Transfer agent and trustee fees..............................   12,500.00
      Information agent fees and expenses..........................    5,000.00
      Miscellaneous................................................    9,318.18
                                                                    -----------
         Total..................................................... $190,000.00
                                                                    ===========
</TABLE>
 
ITEM 15. INDEMNIFICATION OF DIRECTOR AND OFFICERS.
 
    Article VIII of the By-Laws of the Company, in accordance with the
  provisions of Section 145 of the General Corporation Law of Delaware (the
  "Delaware Corporation Law"), provides that the Company shall indemnify any
  person in connection with any threatened, pending or completed legal
  proceeding (other than a legal proceeding by or in the right of the
  Company) by reason of the fact that he is or was a director or officer of
  the Company or is or was serving at the request of the Company as a
  director, officer, employee or agent of another corporation, partnership or
  other enterprise against expenses (including attorneys' fees), judgments,
  fines and amounts paid in settlement actually and reasonably incurred in
  connection with such legal proceeding if he acted in good faith and in a
  manner that he reasonably believed to be in or not opposed to the best
  interests of the Company, and, with respect to any criminal action or
  proceeding, if he had no reasonable cause to believe that his conduct was
  unlawful. If the legal proceeding is by or in the right of the Company, the
  director or officer may be indemnified by the Company against expenses
  (including attorneys' fees) actually and reasonably incurred in connection
  with the defense or settlement of such legal proceeding if he acted in good
  faith and in a manner he reasonably believed to be in or not opposed to the
  best interests of the Company, except that he may not be indemnified in
  respect of any claim, issue or matter as to which he shall have been
  adjudged to be liable to the Company unless a court determines otherwise.
 
    Article VIII of the Company's By-Laws allows the Company to maintain
  director and officer liability insurance on behalf of any person who is or
  was a director or officer of the Company or such person who serves or
  served as director, officer, employee or agent of another corporation,
  partnership or other enterprise at the request of the Company.
 
    Article VI of the Company's Certificate, in accordance with Section
  102(b)(7) of the Delaware Corporation Law, provides that no director of the
  Company shall be personally liable to the Company or its stockholders for
  monetary damages for any breach of his fiduciary duty as a director;
  provided, however, that such clause shall not apply to any liability of a
  director (1) for any breach of his duty of loyalty to the Company or its
  stockholders, (2) for acts or omissions that are not in good faith or
  involve intentional misconduct or a knowing violation of the law, (3) under
  Section 174 of the Delaware Corporation Law, or (4) for any transaction
  from which the director derived an improper personal benefit.
 
    The Declaration of the Trust limits the liability to the Trust and
  certain other persons, and provides for the indemnification by the Company
  of Trustees, their officers, directors and employees and certain other
  persons.
 
                                     II-1
<PAGE>
 
ITEM 16. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES.
 
  A. EXHIBITS
 
  The Exhibits listed in the following Exhibit Index are filed as part of the
Registration Statement:
 
<TABLE>
<CAPTION>
 EXHIBIT
 NUMBER                                DESCRIPTION
 -------                               -----------
 <S>     <C>
   4.1   Certificate of Trust of McKesson Financing Trust.
   4.2   Amended and Restated Declaration of Trust of McKesson Financing Trust,
         dated as of February 20, 1997, among McKesson Corporation, as Sponsor,
         The First National Bank of Chicago, as Institutional Trustee, First
         Chicago Delaware Inc., as Delaware Trustee and William A. Armstrong,
         Ivan D. Meyerson and Nancy A. Miller, as Regular Trustees.
   4.3   Indenture for the 5% Convertible Junior Subordinated Debentures, dated
         as of February 20, 1997, among McKesson Corporation and The First
         National Bank of Chicago, as Debt Trustee.
   4.4   Form of 5% Trust Convertible Preferred Securities (included in Exhibit
         A-1 to Exhibit 4.2 above).
   4.5   Form of 5% Convertible Junior Subordinated Debentures (included in
         Exhibit A to Exhibit 4.3 above).
   4.7   McKesson Corporation Preferred Securities Guarantee Agreement, dated
         as of February 20, 1997, between McKesson Corporation, as Guarantor,
         and The First National Bank of Chicago, as Preferred Guarantor
         Trustee.
   4.8   Restated Certificate of Incorporation of the Company (Exhibit 3.1(1)).
   4.9   Restated By-Laws of the Company, as amended through April 1, 1997
         (Exhibit 4.2(2)).
   4.10  Rights Agreement, dated as of September 14, 1994, by and between the
         Company and First Chicago Trust Company of New York, as Rights Agent
         (Exhibit 4.1(3)).
   5.1   Opinion of Skadden, Arps, Slate, Meagher & Flom LLP as to the legality
         of the Convertible Preferred Securities, Convertible Junior
         Subordinated Debentures, Guarantee and Common Stock of McKeeson
         Corporation being registered hereby.
   8.1   Opinion of Skadden, Arps, Slate, Meagher & Flom LLP as to certain tax
         matters.
  10.1   Registration Rights Agreement, dated February 20, 1997, among McKesson
         Corporation, McKesson Financing Trust and Morgan Stanley & Co.
         Incorporated, as Initial Purchaser.
  12.1   Ratio of Earnings to Fixed Charges of McKesson Corporation.
  23.1   Consent of Skadden, Arps, Slate, Meagher & Flom LLP (included in
         Exhibits 5.1 and 8.1).
  23.2   Independent Auditors' Consent.
  24     Power of Attorney.
  25.1   Form T-1 Statement of Eligibility under the Trust Indenture Act of
         1939, as amended, of The First National Bank of Chicago, as Debt
         Trustee under the 5% Convertible Junior Subordinated Debenture
         Indenture.
  25.2   Form T-1 Statement of Eligibility under the Trust Indenture Act of
         1939, as amended, of The First National Bank of Chicago, as
         Institutional Trustee under the Amended and Restated Declaration of
         Trust.
  25.3   Form T-1 Statement of Eligibility under the Trust Indenture Act of
         1939, as amended, of The First National Bank of Chicago, as Preferred
         Guarantee Trustee under the Guarantee.
- - --------
 
  (1)    Incorporated by reference to designated exhibit to the Company's
         Annual Report on Form 10-K for the fiscal year ended March 31, 1996,
         as amended by Amendment No. 1 on Form 10-K/A, filed on February 13,
         1997.
  (2)    Incorporated by reference to designated exhibit to the Company's
         Registration Statement on Form S-3 filed with the Commission on April
         29, 1997, Registration No. 333-26103.
  (3)    Incorporated by reference to designated exhibit to Amendment No. 3 to
         the Company's Registration Statement on Form 10 filed with the
         Commission on October 27, 1994, File No. 1-13252.
</TABLE>
 
                                      II-2
<PAGE>
 
  B. FINANCIAL STATEMENTS AND SCHEDULES
 
  All schedules for which provision is made in Regulation S-X of the
Securities and Exchange Commission either are not required under the related
instructions or the information required to be included therein has been
included in the financial statements of the Company.
 
ITEM 17. UNDERTAKINGS.
 
  (a) The undersigned registrant hereby undertakes as follows:
 
    (1) To file, during any period in which offers or sales are being made, a
  post-effective amendment to this registration statement:
 
      (i) To include any prospectus required by Section 10(a)(3) of the
    Securities Act of 1933;
 
      (ii) To reflect in the prospectus any facts or events arising after
    the effective date of the registration statement (or the most recent
    post-effective amendment thereof) which, individually or in the
    aggregate, represent a fundamental change in the information set forth
    in the registration statement. Notwithstanding the foregoing, any
    increase or decrease in volume of securities offered (if the total
    dollar value of securities offered would not exceed that which was
    registered) and any deviation from the lower high end of the estimated
    maximum offering range may be reflected in the form of prospectus filed
    with the commission pursuant to Rule 424(b) if, in the aggregate, the
    changes in volume and price represent no more than a 20% change in the
    maximum aggregate offering price set forth in the "Calculation of
    Registration Fee" table in the effective registration statement;
 
    (iii) To include any material information with respect to the plan of
    distribution not previously disclosed in the registration statement or
    any material change to such information in the registration statement;
 
  provided, however, that paragraphs (a)(l)(i) and (a)(l)(ii) do not apply if
  the registration statement is on Form S-3, Form S-8 or Form F-3, and the
  information required to be included in a post-effective amendment by those
  paragraphs is contained in periodic reports filed by the registrant
  pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of
  1934 that are incorporated by reference in the registration statement.
 
    (2) That, for the purpose of determining any liability under the
  Securities Act of 1933, each such post-effective amendment shall be deemed
  to be a new registration statement relating to the securities offered
  therein, and the offering of such securities at that time shall be deemed
  to be the initial bona fide offering thereof.
 
    (3) To remove from registration by means of a post-effective amendment
  any of the securities which remain unsold at the termination of the
  offering.
 
  (b) The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act of 1933, each filing of the
registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Securities Exchange Act of 1934 (and, where applicable, each filing of an
employee benefit plan's annual report pursuant to Section 15(d) of the
Securities Exchange Act of 1934) that is incorporated by reference in the
registration statement shall be deemed to be a new registration statement
relating to the securities offered therein, and the offering of such
securities at that time shall be deemed to be the initial bona fide offering
thereof.
 
  (c) Insofar as indemnification for liabilities arising under the Securities
Act of 1933 may be permitted to directors, officers and controlling persons of
the registrant pursuant to the foregoing provisions, or otherwise, the
registrant has been advised that in the opinion of the Securities and Exchange
Commission such indemnification is against public policy as expressed in the
Securities Act of 1933 and is, therefore, unenforceable. In the event that a
claim for indemnification against such liabilities (other than the payment by
the registrant of expenses incurred or paid by a director, officer or
controlling person of the registrant in the successful defense of any action,
suit or proceeding) is asserted by such director, officer or controlling
person in connection with the securities being registered, the registrant
will, unless in the opinion of its counsel the matter has been settled by
controlling precedent, submit to a court of appropriate jurisdiction the
question of whether such indemnification by it is against public policy as
expressed in the Securities Act of 1933 and will be governed by the final
adjudication of such issue.
 
                                     II-3
<PAGE>
 
  (d) The undersigned registrant hereby undertakes to file an application for
the purpose of determining the eligibility of the trustee to act under
subsection (a) of Section 310 of the Trust Indenture Act in accordance with the
rules and regulations prescribed by the Commission under Section 305(b)(2) of
the Trust Indenture Act.
 
  (e) The Company hereby undertakes that:
 
    (1) For purposes of determining any liability under the Securities Act of
  1933, the information omitted from the form of Prospectus filed as part of
  this Registration Statement in reliance upon Rule 430A and contained in a
  form of Prospectus filed by the Registrants pursuant to Rule 424(b)(1) or
  (4) or 497(h) under the Securities Act shall be deemed to be part of this
  Registration Statement as of the time it was declared effective; and
 
    (2) For purposes of determining any liability under the Securities Act of
  1933, each post-effective amendment that contains a form of Prospectus
  shall be deemed to be a new registration statement relating to the
  securities offered therein, and the offering of such securities at that
  time shall be deemed to be the initial bona fide offering thereof.
 
                                      II-4
<PAGE>

 
                                  SIGNATURES
 
  PURSUANT TO THE REQUIREMENTS OF THE SECURITIES ACT OF 1933, THE REGISTRANT
CERTIFIES THAT IT HAS REASONABLE GROUNDS TO BELIEVE THAT IT MEETS ALL THE
REQUIREMENTS FOR FILING ON FORM S-3 AND HAS DULY CAUSED THIS REGISTRATION
STATEMENT TO BE SIGNED ON ITS BEHALF BY THE UNDERSIGNED, THEREUNTO DULY
AUTHORIZED, IN THE CITY OF SAN FRANCISCO, STATE OF CALIFORNIA, ON MAY 2, 1997.
 
 
                                          McKESSON CORPORATION
 
                                                  /s/ Richard H. Hawkins
                                          By: _________________________________
                                            Name:Richard H. Hawkins
                                            Title: Vice President and Chief
                                                   Financial Officer
 
  Pursuant to the requirements of the Securities Act of 1933, the registration
statement has been signed below by the following persons on behalf of the
Registrant and in the capacities indicated on May 2, 1997.
 
              SIGNATURE                                   TITLE
 
<TABLE>
<CAPTION> 
<S>                                                <C>
                  *                                Chairman of the Board
- - -------------------------------------
          ALAN SEELENFREUND
 
         /s/ Mark A. Pulido                    President and Chief Executive
- - -------------------------------------                     Officer
           MARK A. PULIDO                              and Director
                                               (principal executive officer)
 
       /s/ Richard H. Hawkins                    Vice President and Chief
- - -------------------------------------                Financial Officer
         RICHARD H. HAWKINS                    (principal financial officer)
 
        /s/ Heidi E. Yodowitz                           Controller
- - -------------------------------------         (principal accounting officer)
          HEIDI E. YODOWITZ
 
                  *                                      Director
- - -------------------------------------
         MARY G.F. BITTERMAN
 
                  *                                      Director
- - -------------------------------------
          TULLY M. FRIEDMAN
 
                  *                                      Director
- - -------------------------------------
          JOHN M. PIETRUSKI
 
                  *                                      Director
- - -------------------------------------
          CARL E. REICHARDT
 
                  *                                      Director
- - -------------------------------------
            JANE E. SHAW
 
                  *                                      Director
- - -------------------------------------
       ROBERT H. WATERMAN, JR.
 
           /s/ Nancy A. Miller
*By: ________________________________
           NANCY A. MILLER
          ATTORNEY-IN-FACT
 
</TABLE> 
                                     II-5
<PAGE>

 
                                  SIGNATURES
 
  PURSUANT TO THE REQUIREMENTS OF THE SECURITIES ACT OF 1933, MCKESSON
FINANCING TRUST CERTIFIES THAT IT HAS REASONABLE GROUNDS TO BELIEVE THAT IT
MEETS ALL THE REQUIREMENTS FOR FILING ON FORM S-3 AND HAS DULY CAUSED THIS
REGISTRATION STATEMENT TO BE SIGNED ON ITS BEHALF BY THE UNDERSIGNED,
THEREUNTO DULY AUTHORIZED, IN THE CITY OF SAN FRANCISCO, STATE OF CALIFORNIA,
ON MAY 2, 1997.
 
                                          McKESSON FINANCING TRUST
 
                                          By __________________________________
                                                  /s/ Ivan D. Meyerson
                                                    Ivan D. Meyerson
                                                         Trustee
 
                                          By __________________________________
                                                   /s/ Nancy A. Miller
                                                     Nancy A. Miller
                                                         Trustee
 
                                          By __________________________________
                                                /s/ William A. Armstrong
                                                  William A. Armstrong
                                                         Trustee
 
 
                                     II-6

<PAGE>
 
                                                                     Exhibit 4.1
                                                                     -----------

                             CERTIFICATE OF TRUST

          The undersigned, the trustees of McKesson Financing Trust, desiring
to form a business trust pursuant to Delaware Business Trust Act, 12 Del. C. (S)
                                                                     ---- --    
3801 et seq., hereby certify as follows:
     -- ---                             

          1.   The name of the business trust being formed hereby (the "Trust")
               is "McKesson Financing Trust".

          2.   The name and business address of the trustee of the Trust which
               has its principal place of business in the State of Delaware is
               as follows:
 
               First Chicago Delaware Inc.
               300 King Street
               Wilmington, DE 19801
 
          3.   This Certificate of Trust shall be effective as of the date of
               its filing.

Dated:  February 5, 1997
                                      /s/ William A. Armstrong
                              -----------------------------------
                              Name:  William A. Armstrong
                              Title: Regular Trustee


                                      /s/ Ivan D. Meyerson
                              -----------------------------------
                              Name:  Ivan D. Meyerson
                              Title: Regular Trustee


                                      /s/ Nancy Miller
                              -----------------------------------
                              Name:  Nancy Miller
                              Title: Regular Trustee
<PAGE>
 
                              THE FIRST NATIONAL BANK OF
                              CHICAGO, as Institutional Trustee
                              By:    /s/ Richard D. Manella
                                  -------------------------------
                                    Name:  Richard D. Manella
                                    Title: Vice President


                              FIRST CHICAGO DELAWARE 
                              INC., as Delaware Trustee
                              By:    /s/ Richard D. Manella
                                  -------------------------------
                                    Name:  Richard D. Manella
                                    Title: Vice President

                                       2

<PAGE>
 
                                                                     Exhibit 4.2
                                                                     -----------
- - --------------------------------------------------------------------------------


                       AMENDED AND RESTATED DECLARATION

                                   OF TRUST



                           MCKESSON FINANCING TRUST



                         DATED AS OF FEBRUARY 20, 1997


- - --------------------------------------------------------------------------------
<PAGE>
 
                               TABLE OF CONTENTS

<TABLE> 
<CAPTION> 
                                                                            Page
                                                                            ----
<S>                                                                         <C> 
                                   ARTICLE I

                        INTERPRETATION AND DEFINITIONS

SECTION 1.1.   Definitions..................................................   1


                                  ARTICLE II

                              TRUST INDENTURE ACT

SECTION 2.1.   Trust Indenture Act: Application.............................   8
SECTION 2.2.   Lists of Holders of Securities...............................   9
SECTION 2.3.   Reports by the Institutional Trustee.........................   9
SECTION 2.4.   Periodic Reports to Institutional Trustee....................   9
SECTION 2.5.   Evidence of Compliance with Conditions Precedent.............  10
SECTION 2.6.   Events of Default; Waiver....................................  10
SECTION 2.7.   Event of Default; Notice.....................................  11
                                                                
                                  ARTICLE III                                  
                                                                               
                                 ORGANIZATION                                  
                                                                               
SECTION 3.1.   Name.........................................................  12
SECTION 3.2.   Office.......................................................  12
SECTION 3.3.   Purpose......................................................  12
SECTION 3.4.   Authority....................................................  13
SECTION 3.5.   Title to Property of the Trust...............................  13
SECTION 3.6.   Powers and Duties of the Regular Trustees....................  13
SECTION 3.7.   Prohibition of Actions by the Trust and the Trustees.........  17
SECTION 3.8.   Powers and Duties of the Institutional Trustee...............  17
SECTION 3.9.   Certain Duties and Responsibilities of the Institutional         
                Trustee.....................................................  19
SECTION 3.10.  Certain Rights of Institutional Trustee......................  21
SECTION 3.11.  Delaware Trustee.............................................  23
SECTION 3.12.  Execution of Documents.......................................  23
SECTION 3.13.  Not Responsible for Recitals or Issuance of Securities.......  24
SECTION 3.14.  Duration of Trust............................................  24
SECTION 3.15.  Mergers......................................................  24
</TABLE>

                                       i
<PAGE>
 
<TABLE> 
<S>                                                                          <C>
                                  ARTICLE IV

                                    SPONSOR

SECTION 4.1.   Sponsor's Purchase of Common Securities...................... 25
SECTION 4.2.   Responsibilities of the Sponsor.............................. 26

                                   ARTICLE V

                                   TRUSTEES
 
SECTION 5.1.   Number of Trustees........................................... 27
SECTION 5.2.   Delaware Trustee............................................. 27
SECTION 5.3.   Institutional Trustee; Eligibility........................... 27
SECTION 5.4.   Certain Qualifications of Regular Trustees and Delaware      
                Trustee Generally........................................... 28
SECTION 5.5.   Regular Trustees...........................                   28
SECTION 5.6.   Appointment, Removal and Resignation of Trustees............. 29
SECTION 5.7.   Vacancies Among Trustees..................................... 30
SECTION 5.8.   Effect of Vacancies.......................................... 30
SECTION 5.9.   Meetings..................................................... 30
SECTION 5.10.  Delegation of Power.......................................... 31
SECTION 5.11.  Merger, Conversion, Consolidation or Succession to            
                Business.................................................... 31
 
                                  ARTICLE VI

                                 DISTRIBUTIONS

SECTION 6.1.   Distributions................................................ 32 

                                  ARTICLE VII

                            ISSUANCE OF SECURITIES
SECTION 7.1.   General Provisions Regarding Securities...................... 32 
SECTION 7.2.   Execution and Authentication................................. 32 
SECTION 7.3.   Form and Dating.............................................. 33 
SECTION 7.4.   Paying Agent................................................. 34
</TABLE>

                                      ii
<PAGE>
 
<TABLE>
<S>                                                                          <C>
                                 ARTICLE VIII

                             TERMINATION OF TRUST

SECTION 8.1.   Termination of Trust......................................... 34 
                                                                                
                                                                                
                                  ARTICLE IX                                    
                                                                                
                             TRANSFER OF INTERESTS                              
                                                                                
SECTION 9.1.   Transfer of Securities....................................... 35 
SECTION 9.2.   Transfer of Certificates..................................... 38 
SECTION 9.3.   Deemed Security Holders...................................... 38 
SECTION 9.4.   Book Entry Interests......................................... 38 
SECTION 9.5.   Notices to Clearing Agency................................... 41 
SECTION 9.6.   Appointment of Successor Clearing Agency..................... 41 
SECTION 9.7.   Definitive Convertible Preferred Security Certificates Under     
                Certain Circumstances....................................... 41 
SECTION 9.8.   Mutilated, Destroyed, Lost or Stolen Certificates............ 42 
                                                                                
                                   ARTICLE X                                    
                                                                                
               LIMITATION OF LIABILITY OF HOLDERS OF SECURITIES,                
                              TRUSTEES OR OTHERS                                
                                                                                
SECTION 10.1.  Liability.................................................... 43 
SECTION 10.2.  Exculpation.................................................. 43 
SECTION 10.3.  Fiduciary Duty............................................... 44 
SECTION 10.4.  Indemnification.............................................. 44 
SECTION 10.5.  Outside Business............................................. 47 
                                                                                
                                  ARTICLE XI                                    
                                                                                
                                  ACCOUNTING                                    
                                                                                
SECTION 11.1.  Fiscal Year.................................................. 48 
SECTION 11.2.  Certain Accounting Matters................................... 48 
SECTION 11.3.  Banking...................................................... 48 
SECTION 11.4.  Withholding.................................................. 49 
</TABLE>                                  

                                      iii
<PAGE>
 
<TABLE>                                                                         
<S>                                                                          <C>
                                  ARTICLE XII

                            AMENDMENTS AND MEETINGS

SECTION 12.1.  Amendments................................................... 49 
SECTION 12.2.  Meetings of the Holders of Securities; Action by Written  
                Consent..................................................... 51

                                 ARTICLE XIII

                 REPRESENTATIONS OF INSTITUTIONAL TRUSTEE AND
                               DELAWARE TRUSTEE

SECTION 13.1.  Representations and Warranties of Institutional Trustee...... 53 
SECTION 13.2.  Representations and Warranties of Delaware Trustee........... 53 


                                  ARTICLE XIV

                                 MISCELLANEOUS

SECTION 14.1.  Notices...................................................... 54
SECTION 14.2.  Governing Law................................................ 55
SECTION 14.3.  Intention of the Parties..................................... 55
SECTION 14.4.  Headings..................................................... 56
SECTION 14.5.  Successors and Assign........................................ 56
SECTION 14.6.  Partial Enforceability....................................... 56
SECTION 14.7.  Counterparts................................................. 56
</TABLE>

                                      iv
<PAGE>
 
                            CROSS-REFERENCE TABLE*

<TABLE>
<CAPTION>
Section of
Trust Indenture Act                                               Section of   
of 1939, as amended                                               Declaration  
- - -------------------                                               -----------  
<S>                                                               <C>          
310(a)   .......................................................   5.3(a)      
310(c)   .......................................................   Inapplicable
311(c)   .......................................................   Inapplicable
312(a)   .......................................................   2.2(a)      
312(b)   .......................................................   2.2(b)      
313      .......................................................   2.3         
314(a)   .......................................................   2.4         
314(b)   .......................................................   Inapplicable
314(c)   .......................................................   2.5         
314(d)   .......................................................   Inapplicable
314(f)   .......................................................   Inapplicable
315(a)   .......................................................   3.9(b)      
315(c)   .......................................................   3.9(a)      
315(d)   .......................................................   3.9(a)      
316(a)   .......................................................   Annex I      
316(c)   .......................................................   3.6(e)       
</TABLE> 

__________

* This Cross-Reference table does not constitute part of the Declaration and
  shall not affect the interpretation of any of its terms or provisions.

                                       v
<PAGE>
 
                             AMENDED AND RESTATED
                             DECLARATION OF TRUST
                                      OF
                           McKESSON FINANCING TRUST

                               February 20, 1997

     AMENDED AND RESTATED DECLARATION OF TRUST ("Declaration") dated and
effective as of February 20, 1997, by the Trustees (as defined herein), the
Sponsor (as defined herein) and by the holders, from time to time, of undivided
beneficial interests in the Trust to be issued pursuant to this Declaration;

     WHEREAS, the Trustees and the Sponsor established McKesson Financing Trust
(the "Trust"), a trust under the Delaware Business Trust Act pursuant to a
Declaration of Trust dated as of February 5, 1997 (the "Original Declaration"),
and a Certificate of Trust filed with the Secretary of State of the State of
Delaware on February 5, 1997, for the sole purpose of issuing and selling
certain securities representing undivided beneficial interests in the assets of
the Trust and investing the proceeds thereof in certain Debentures (as defined
herein) of the Debenture Issuer (as defined herein);

     WHEREAS, as of the date hereof, no interests in the Trust have been issued;
and

     WHEREAS, all of the Trustees and the Sponsor, by this Declaration, amend
and restate each and every term and provision of the Original Declaration;

     NOW, THEREFORE, it being the intention of the parties hereto to continue
the Trust as a business trust under the Business Trust Act and that this
Declaration constitutes the governing instrument of such business trust, the
Trustees declare that all assets contributed to the Trust will be held in trust
for the benefit of the holders, from time to time, of the securities
representing undivided beneficial interests in the assets of the Trust issued
hereunder, subject to the provisions of this Declaration.


                                   ARTICLE I

                        INTERPRETATION AND DEFINITIONS

     SECTION 1.1.  Definitions.

     Unless the context otherwise requires:

     (a) Capitalized terms used in this Declaration but not defined in the
preamble above have the respective meanings assigned to them in this Section
1.1;

     (b) a term defined anywhere in this Declaration has the same meaning
throughout;

                                       1
<PAGE>
 
     (c) all references to "the Declaration" or "this Declaration" are to this
Declaration as modified, supplemented or amended from time to time;

     (d) all references in this Declaration to Articles and Sections and Annexes
and Exhibits are to Articles and Sections of and Annexes and Exhibits of or to
this Declaration unless otherwise specified;

     (e) a term defined in the Trust Indenture Act has the same meaning when
used in this Declaration unless otherwise defined in this Declaration or unless
the context otherwise requires; and

     (f) a reference to the singular includes the plural and vice versa.

     "144A Global Certificate" has the meaning assigned such term in Section
9.4(b).

     "Affiliate" has the same meaning as given to that term in Rule 405 of the
Securities Act or any successor rule thereunder.

     "Agent" means any Paying Agent or Conversion Agent.

     "Authorized Officer" of a Person means any Person that is authorized to
bind such Person.

     "Book Entry Interest" means a beneficial interest in a Global Certificate,
ownership and transfers of which shall be maintained and made through book
entries by a Clearing Agency as described in Section 9.4.

     "Business Day" means any day other than a Saturday, Sunday or any other day
on which banking institutions in New York, New York or Wilmington, Delaware are
permitted or required by any applicable law to close.

     "Business Trust Act" means Chapter 38 of Title 12 of the Delaware Code, 12
Del. Code (S)3801 et seq., as it may be amended from time to time, or any
successor legislation.

     "Certificate" means a Common Security Certificate or a Convertible
Preferred Security Certificate.

     "Clearing Agency" means an organization registered as a "Clearing Agency"
pursuant to Section 17A of the Exchange Act that is acting as depositary for the
Convertible Preferred Securities and in whose name or in the name of a nominee
of that organization shall be registered a Global Certificate and which shall
undertake to effect book entry transfers and pledges of the Convertible
Preferred Securities.

     "Clearing Agency Participant" means a broker, dealer, bank, other financial
institution or other Person for whom from time to time the Clearing Agency
effects book entry transfers and pledges of securities deposited with the
Clearing Agency.

                                       2
<PAGE>
 
     "Closing Date" means February 20, 1997.

     "Closing Price" has the meaning specified in Annex I.

     "Code" means the Internal Revenue Code of 1986, as amended from time to
time, or any successor legislation.

     "Commission" means the Securities and Exchange Commission.

     "Common Securities Guarantee" means the guarantee agreement to be dated as
of February 20, 1997 of the Sponsor in respect of the Common Securities.

     "Common Securities Registration Rights Agreement" means the Registration
Rights Agreement dated February 20, 1997, between McKesson Corporation and the
Trust, relating to the Common Securities.

     "Common Security" has the meaning specified in Section 7.1.

     "Common Security Certificate" means a definitive certificate in fully
registered form representing a Common Security substantially in the form of
Exhibit A-2.

     "Common Stock" means the common stock of McKesson Corporation, a Delaware
corporation, par value $.01 per share, and any other shares of common stock as
may constitute "Common Stock" under the Indenture.

     "Company Indemnified Person" means (a) any Regular Trustee; (b) any
Affiliate of any Regular Trustee; (c) any officers, directors, shareholders,
members, partners, employees, representatives or agents of any Regular Trustee;
or (d) any officer, employee or agent of the Trust or its Affiliates.

     "Conversion Agent" has the meaning specified in Section 7.4.

     "Convertible Preferred Securities Guarantee" means the guarantee agreement
to be dated as of February 20, 1997, of the Sponsor in respect of the
Convertible Preferred Securities.

     "Convertible Preferred Security" has the meaning specified in Section 7.1.

     "Convertible Preferred Security Beneficial Owner" means, with respect to a
Book Entry Interest, a Person who is the beneficial owner of such Book Entry
Interest, as reflected on the books of the Clearing Agency, or on the books of a
Person maintaining an account with such Clearing Agency (directly as a Clearing
Agency Participant or as an indirect participant, in each case in accordance
with the rules of such Clearing Agency).

     "Convertible Preferred Security Certificate" means a certificate
representing a Preferred Security substantially in the form of Exhibit A-1.

                                       3
<PAGE>
 
     "Corporate Trust Office" means the office of the Institutional Trustee at
which the corporate trust business of the Institutional Trustee shall, at any
particular time, be principally administered, which office at the date of
execution of this Agreement is located at One First National Plaza, Suite 0126,
Chicago, Illinois 60670-0126, Attention: Corporate Trust Services Division.

     "Covered Person" means: (a) any officer, director, shareholder, partner,
member, representative, employee or agent of (i) the Trust or (ii) the Trust's
Affiliates; and (b) any Holder of Securities.

     "Debenture Issuer" means McKesson Corporation, a Delaware corporation, in
its capacity as issuer of the Debentures under the Indenture.

     "Debenture Trustee" means The First National Bank of Chicago, as trustee
under the Indenture until a successor is appointed thereunder, and thereafter
means such successor trustee.

     "Debentures" means the series of Debentures to be issued by the Debenture
Issuer under the Indenture to be held by the Institutional Trustee, a specimen
certificate for such series of Debentures being Exhibit B.

     "Delaware Trustee" has the meaning set forth in Section 5.1.

     "Definitive Convertible Preferred Security Certificates" has the meaning
set forth in Section 9.4.

     "Distribution" means a distribution payable to Holders of Securities in
accordance with Section 6.1.

     "DTC" means The Depository Trust Company, the initial Clearing Agency.

     "Event of Default" in respect of the Securities means an Event of Default
(as defined in the Indenture) has occurred and is continuing in respect of the
Debentures.

     "Exchange Act" means the Securities Exchange Act of 1934, as amended from
time to time, or any successor legislation.

     "Fiduciary Indemnified Person" has the meaning set forth in Section
10.4(b).

     "Global Certificate" has the meaning set forth in Section 9.4(b).

     "Holder" means a Person in whose name a Certificate representing a Security
is registered, such Person being a beneficial owner within the meaning of the
Business Trust Act.

     "Indemnified Person" means each Company Indemnified Person and each
Fiduciary Indemnified Person.

                                       4
<PAGE>
 
     "Indenture" means the Indenture dated as of February 20, 1997 between the
Debenture Issuer and the Debenture Trustee.

     "Institutional Trustee" means the Trustee meeting the eligibility
requirements set forth in Section 5.3.

     "Institutional Trustee Account" has the meaning set forth in Section
3.8(c).

     "Investment Company" means an investment company as defined in the
Investment Company Act.

     "Investment Company Act" means the Investment Company Act of 1940, as
amended from time to time, or any successor legislation.

     "Investment Company Event" has the meaning set forth in Annex I hereto.

     "Legal Action" has the meaning set forth in Section 3.6(g).

     "Liquidated Distribution" has the meaning specified in the terms of the
Securities as set forth in Annex I.

     "Majority in liquidation amount of the Securities" means, except as
provided in the terms of the Convertible Preferred Securities or by the Trust
Indenture Act, Holder(s) of outstanding Securities voting together as a single
class or, as the context may require, Holders of outstanding Convertible
Preferred Securities or Holders of outstanding Common Securities voting
separately as a class, who are the record owners of more than 50% of the
aggregate liquidation amount (including the stated amount that would be paid on
redemption, liquidation or otherwise, plus accrued and unpaid Distributions to
the date upon which the voting percentages are determined) of all outstanding
Securities of the relevant class.

     "Ministerial Action" has the meaning set forth in the terms of the
Securities as set forth in Annex I.

     "Non-U.S. Person" means a Person other than a U.S. person (as such term is
defined in Regulation S).

     "Offered Securities" means the Convertible Preferred Securities, the
Convertible Preferred Securities Guarantee, the Debentures, the shares of Common
Stock issuable upon conversion of the Debentures and the Rights attached
thereto.

     "Officers' Certificate" means, with respect to any Person, a certificate
signed by two Authorized Officers of such Person.  Any Officers' Certificate
delivered with respect to compliance with a condition or covenant provided for
in this Declaration shall include:

     (a) a statement that each officer signing the Certificate has read the
covenant or condition and the definitions relating thereto;

                                       5
<PAGE>
 
     (b) a brief statement of the nature and scope of the examination or
investigation undertaken by each officer in rendering the Certificate;

     (c) a statement that each such officer has made such examination or
investigation as, in such officer's opinion, is necessary to enable such officer
to express an informed opinion as to whether or not such covenant or condition
has been complied with; and

     (d) a statement as to whether, in the opinion of each such officer, such
condition or covenant has been complied with.

     "Option Closing Date" means the date of closing of any sale of Additional
Securities (as defined in the Placement Agreement).

     "Paying Agent" has the meaning specified in Section 3.8(h).

     "Payment Amount" has the meaning set forth in Section 6.1.

     "Person" means any individual, corporation, estate, partnership, joint
venture, association, joint stock company, limited liability company, trust,
unincorporated association, or government or any agency or political subdivision
thereof, or any other entity of whatever nature.

     "Placement Agreement" means the Placement Agreement for the offering and
sale of Convertible Preferred Securities in the form of Exhibit C.

     "PORTAL Market" means the Private Offerings, Resales and Trading through
Automated Linkages Market operated by the National Association of Securities
Dealers, Inc. or any successor thereto.

     "Preferred Securities Registration Rights Agreement" means the Registration
Rights Agreement dated February 20, 1997, among McKesson Corporation, the Trust
and Morgan Stanley & Co. Incorporated, as Initial Purchaser, relating to the
Convertible Preferred Securities.

     "QIB" means a "qualified institutional buyer" as defined in Rule 144A.

     "Quorum" means a majority of the Regular Trustees or, if there are only two
Regular Trustees, both of them.

     "Registration Rights Agreements" means the Preferred Securities
Registration Rights Agreement and the Common Securities Registration Rights
Agreement.

     "Regular Trustee" has the meaning set forth in Section 5.1.

     "Regulation S" means Regulation S under the Securities Act or any successor
provision.

     "Regulation S Global Certificate" has the meaning assigned such term in
Section 9.4(b).

                                       6
<PAGE>
 
     "Related Party" means, with respect to the Sponsor, any direct or indirect
wholly owned subsidiary of the Sponsor or any other Person that owns, directly
or indirectly, 100% of the outstanding voting securities of the Sponsor.

     "Responsible Officer" means, with respect to the Institutional Trustee, any
officer within the Corporate Trust Office of the Institutional Trustee,
including any vice president, any assistant vice president, any assistant
secretary, the treasurer, any assistant treasurer or other officer of the
Corporate Trust Office of the Institutional Trustee customarily performing
functions similar to those performed by any of the above designated officers and
also means, with respect to a particular corporate trust matter, any other
officer to whom such matter is referred because of that officer's knowledge of
and familiarity with the particular subject.

     "Restricted Security" has the meaning specified in Section 9.1(d).

     "Rights" has the meaning specified in the Rights Agreement, dated September
14, 1994, between the Sponsor and The First Chicago Trust Company of New York.

     "Rule 144A" means Rule 144A as promulgated under the Securities Act, or any
successor rule.

     "Rule 144(k)" means Rule 144(k) as promulgated under the Securities Act, or
any successor rule.

     "Rule 3a-5" means Rule 3a-5 under the Investment Company Act or any
successor rule.

     "Securities" means the Common Securities and the Convertible Preferred
Securities.

     "Securities Act" means the Securities Act of 1933, as amended from time to
time, or any successor legislation.

     "Securities Guarantees" means the Common Securities Guarantee and the
Convertible Preferred Securities Guarantee.

     "Special Event" has the meaning set forth in Annex I hereto.

     "Sponsor" or "McKesson" means McKesson Corporation, a Delaware corporation,
or any successor entity in a merger, consolidation or amalgamation, in its
capacity as sponsor of the Trust.

     "Super Majority" has the meaning set forth in Section 2.6(a)(ii).

     "Tax Event" has the meaning set forth in Annex I hereto.

     "Transfer Restriction Termination Date" means the earlier of the first date
on which (i) the Securities and any Common Stock issued or issuable upon the
conversion or exchange thereof (other than (A) Securities acquired by the Trust
or any Affiliate thereof and (B) Common 

                                       7
<PAGE>
 
Stock issued upon the conversion or exchange of any Security described in clause
(A) above) may be sold pursuant to Rule 144(k) and (ii) all the Securities have
been sold pursuant to an effective registration statement.

     "Treasury Regulations" means the income tax regulations, including
temporary and proposed regulations, promulgated under the Code by the United
States Treasury.

     "Trustee" or "Trustees" means each Person who has signed this Declaration
as a trustee, so long as such Person shall continue in office in accordance with
the terms hereof, and all other Persons who may from time to time be duly
appointed, qualified and serving as Trustees in accordance with the provisions
hereof, and references herein to a Trustee or the Trustees shall refer to such
Person or Persons solely in their capacity as trustees hereunder.

     "Trust Indenture Act" means the Trust Indenture Act of 1939, as amended
from time to time, or any successor legislation.

     "Trust Property" means (i) the Debentures, (ii) any cash on deposit in, or
owing to, the Institutional Trustee Account and (iii) all proceeds and rights in
respect of the foregoing to be held by the Institutional Trustee pursuant to the
terms of this Declaration for the benefit of the Securityholders.

     "25% in liquidation amount of the Securities" means, except as provided in
the terms of the Convertible Preferred Securities or by the Trust Indenture Act,
Holder(s) of outstanding Securities voting together as a single class or, as the
context may require, Holders of outstanding Convertible Preferred Securities or
Holders of outstanding Common Securities voting separately as a class, who are
the record owners of 25% or more of the aggregate liquidation amount (including
the stated amount that would be paid on redemption, liquidation or otherwise,
plus accrued and unpaid Distributions to the date upon which the voting
percentages are determined) of all outstanding Securities of the relevant class.


                                  ARTICLE II

                              TRUST INDENTURE ACT

     SECTION 2.1.  Trust Indenture Act: Application.

     (a) This Declaration is subject to the provisions of the Trust Indenture
Act that are required to be part of this Declaration and shall, to the extent
applicable, be governed by such provisions.  The Trust Indenture Act shall be
applicable to this Declaration except as otherwise set forth herein, as if the
Securities had been sold pursuant to an effective registration statement.

     (b) The Institutional Trustee shall be the only Trustee which is a Trustee
for the purposes of the Trust Indenture Act.

                                       8
<PAGE>
 
     (c) If, and to the extent that, any provision of this Declaration limits,
qualifies or conflicts with the duties imposed by (S)(S) 310 to 317, inclusive,
of the Trust Indenture Act, such duties imposed under the Trust Indenture Act
shall control.

     (d) The application of the Trust Indenture Act to this Declaration shall
not affect the nature of the Securities as equity securities representing
undivided beneficial interests in the assets of the Trust.

     SECTION 2.2.  Lists of Holders of Securities.

     (a) Each of the Sponsor and the Regular Trustees on behalf of the Trust
shall provide the Institutional Trustee (i) within 14 days after each record
date for payment of Distributions, a list in such form as the Institutional
Trustee may reasonably require of the names and addresses of the Holders of the
Securities ("List of Holders") as of such record date, provided that, neither
the Sponsor nor the Regular Trustees on behalf of the Trust shall be obligated
to provide such List of Holders at any time the List of Holders does not differ
from the most recent List of Holders given to the Institutional Trustee by the
Sponsor and the Regular Trustees on behalf of the Trust, and (ii) at any other
time, within 30 days of receipt by the Trust of a written request for a List of
Holders as of a date no more than 14 days before such List of Holders is given
to the Institutional Trustee.  The Institutional Trustee shall preserve, in as
current a form as is reasonably practicable, all information contained in the
Lists of Holders given to it or which it receives in the capacity as Paying
Agent (if acting in such capacity), provided that, the Institutional Trustee may
destroy any List of Holders previously given to it on receipt of a new List of
Holders.

     (b) The Institutional Trustee shall comply with its obligations under
(S)(S) 311(a), 311(b) and 312(b) of the Trust Indenture Act.

     SECTION 2.3.  Reports by the Institutional Trustee.

     Within 60 days after May 15 of each year, the Institutional Trustee shall
provide to the Holders of the Convertible Preferred Securities such reports as
are required by (S) 313 of the Trust Indenture Act, if any, in the form and in
the manner provided by (S) 313 of the Trust Indenture Act.  The Institutional
Trustee shall also comply with the requirements of (S) 313(d) of the Trust
Indenture Act.

     SECTION 2.4.  Periodic Reports to Institutional Trustee.

     Each of the Sponsor and the Regular Trustees on behalf of the Trust shall
provide to the Institutional Trustee such documents, reports and information as
required by (S) 314 (if any) and the compliance certificate required by (S) 314
of the Trust Indenture Act in the form, in the manner and at the times required
by (S) 314 of the Trust Indenture Act.

     Delivery of such reports, information and documents to the Institutional
Trustee is for informational purposes only and the Institutional Trustee's
receipt of such shall not constitute constructive notice of any information
contained therein or determinable from information

                                       9
<PAGE>
 
contained therein, including the Sponsor's compliance with any of its covenants
hereunder (as to which the Institutional Trustee is entitled to rely exclusively
on Officers' Certificates).

     SECTION 2.5.  Evidence of Compliance with Conditions Precedent.

     Each of the Sponsor and the Regular Trustees on behalf of the Trust shall
provide to the Institutional Trustee such evidence of compliance with any
conditions precedent, if any, provided for in this Declaration that relate to
any of the matters set forth in (S) 314(c) of the Trust Indenture Act.  Any
certificate or opinion required to be given by an officer pursuant to (S)
314(c)(1) may be given in the form of an Officers' Certificate.

     SECTION 2.6.  Events of Default; Waiver.

     (a) The Holders of a Majority in liquidation amount of Convertible
Preferred Securities may by vote on behalf of the Holders of all of the
Convertible Preferred Securities, waive any past Event of Default in respect of
the Convertible Preferred Securities and its consequences, provided that, if the
underlying Event of Default under the Indenture:

         (i) is not waivable under the Indenture, the Event of Default under the
     Declaration shall also not be waivable; or

        (ii) requires the consent or vote of greater than a majority in
     principal amount of the holders of the Debentures (a "Super Majority") to
     be waived under the Indenture, the Event of Default under the Declaration
     may only be waived by the vote of the Holders of at least the proportion in
     liquidation amount of the Convertible Preferred Securities that the
     relevant Super Majority represents of the aggregate principal amount of the
     Debentures outstanding.

     The foregoing provisions of this Section 2.6(a) shall be in lieu of (S)
316(a)(1)(B) of the Trust Indenture Act and such (S) 316(a)(1)(B) of the Trust
Indenture Act is hereby expressly excluded from this Declaration and the
Securities, as permitted by the Trust Indenture Act.  Upon such waiver, any such
default shall cease to exist, and any Event of Default with respect to the
Convertible Preferred Securities arising therefrom shall be deemed to have been
cured, for every purpose of this Declaration, but no such waiver shall extend to
any subsequent or other default or an Event of Default with respect to the
Convertible Preferred Securities or impair any right consequent thereon.  Any
waiver by the Holders of the Convertible Preferred Securities of an Event of
Default with respect to the Convertible Preferred Securities shall also be
deemed to constitute a waiver by the Holders of the Common Securities of any
such Event of Default with respect to the Common Securities for all purposes of
this Declaration without any further act, vote, or consent of the Holders of the
Common Securities.

     (b) The Holders of a Majority in liquidation amount of the Common
Securities may, by vote, on behalf of the Holders of all of the Common
Securities, waive any past Event of Default with respect to the Common
Securities and its consequences, provided that, if the underlying Event of
Default under the Indenture:

                                       10
<PAGE>
 
         (i) is not waivable under the Indenture, except where the Holders of
     the Common Securities are deemed to have waived such Event of Default under
     the Declaration as provided below in this Section 2.6(b), the Event of
     Default under the Declaration shall also not be waivable; or

        (ii) requires the consent or vote of a Super Majority to be waived,
     except where the Holders of the Common Securities are deemed to have waived
     such Event of Default under the Declaration as provided below in this
     Section 2.6(b), the Event of Default under the Declaration may only be
     waived by the vote of the Holders of at least the proportion in liquidation
     amount of the Common Securities that the relevant Super Majority represents
     of the aggregate principal amount of the Debentures outstanding;

provided further, that each Holder of Common Securities will be deemed to have
waived any such Event of Default and all Events of Default with respect to the
Common Securities and its consequences until all Events of Default with respect
to the Convertible Preferred Securities have been cured, waived or otherwise
eliminated, and until such Events of Default have been so cured, waived or
otherwise eliminated, the Institutional Trustee shall act solely on behalf of
the Holders of the Convertible Preferred Securities and only the Holders of the
Convertible Preferred Securities will have the right to direct the Institutional
Trustee to act in accordance with the terms of the Securities.  The foregoing
provisions of this Section 2.6(b) shall be in lieu of (S)(S) 316(a)(1)(A) and
316(a)(1)(B) of the Trust Indenture Act and such (S)(S) 316(a)(1)(A) and
316(a)(1)(B) of the Trust Indenture Act are hereby expressly excluded from this
Declaration and the Securities, as permitted by the Trust Indenture Act.
Subject to the foregoing provisions of this Section 2.6(b), upon such waiver,
any such default shall cease to exist and any Event of Default with respect to
the Common Securities arising therefrom shall be deemed to have been cured for
every purpose of this Declaration, but no such waiver shall extend to any
subsequent or other default or Event of Default with respect to the Common
Securities or impair any right consequent thereon.

     (c) A waiver of an Event of Default under the Indenture by the
Institutional Trustee at the direction of the Holders of the Convertible
Preferred Securities, constitutes a waiver of the corresponding Event of Default
under this Declaration.  The foregoing provisions of this Section 2.6(c) shall
be in lieu of (S) 316(a)(1)(B) of the Trust Indenture Act and such (S)
316(a)(1)(B) of the Trust Indenture Act is hereby expressly excluded from this
Declaration and the Securities, as permitted by the Trust Indenture Act.

     SECTION 2.7.  Event of Default; Notice.

     (a) The Institutional Trustee shall, within 90 days after the occurrence of
an Event of Default actually known to a Responsible Officer of the Institutional
Trustee, transmit by mail, first class postage prepaid, to the Holders of the
Securities, notices of all such defaults with respect to the Securities unless
such defaults have been cured before the giving of such notice (the term
"defaults" for the purposes of this Section 2.7(a) being hereby defined to be an
Event of Default as defined in the Indenture, not including any periods of grace
provided for therein and irrespective of the giving of any notice provided
therein); provided that, except for a default in the payment of principal of (or
premium, if any) or interest on any of the Debentures or in the

                                       11
<PAGE>
 
payment of any sinking fund installment established for the Debentures, the
Institutional Trustee shall be protected in withholding such notice if and so
long as a Responsible Officer of the Institutional Trustee in good faith
determines that the withholding of such notice is in the interests of the
Holders of the Securities.  Any such notice given pursuant to this Section
2.7(a) shall state that an Event of Default under the Indenture also constitutes
an Event of Default under this Declaration.

     (b) The Institutional Trustee shall not be deemed to have knowledge of any
default except:

         (i) a default under Sections 5.1(a) and 5.1(b) of the Indenture; or

        (ii) any default as to which the Institutional Trustee shall have
     received written notice or of which a Responsible Officer of the
     Institutional Trustee charged with the administration of the Declaration
     shall have actual knowledge.


                                  ARTICLE III

                                 ORGANIZATION

     SECTION 3.1.  Name.

     The Trust is named "McKesson Financing Trust" as such name may be modified
from time to time by the Regular Trustees following written notice to the
Holders of Securities.  The Trust's activities may be conducted under the name
of the Trust or any other name deemed advisable by the Regular Trustees.

     SECTION 3.2.  Office.

     The address of the principal office of the Trust is c/o McKesson
Corporation, McKesson Plaza, One Post Street, San Francisco, CA, 94104.  On at
least ten Business Days written notice to the Holders of Securities, the Regular
Trustees may designate another principal office.

     SECTION 3.3.  Purpose.

     The exclusive purposes and functions of the Trust are (a) to issue and sell
Securities and use the proceeds from such sale to acquire the Debentures, and
(b) except as otherwise limited herein, to engage in only those other activities
necessary, or incidental thereto.  The Trust shall not borrow money, issue debt
or reinvest proceeds derived from investments, pledge any of its assets, or
otherwise undertake (or permit to be undertaken) any activity that would cause
the Trust not to be classified for United States federal income tax purposes as
a grantor trust.

                                       12
<PAGE>
 
     SECTION 3.4.  Authority.

     (a) Subject to the limitations provided in this Declaration and to the
specific duties of the Institutional Trustee, the Regular Trustees shall have
exclusive and complete authority to carry out the purposes of the Trust.  An
action taken by the Regular Trustees in accordance with their powers shall
constitute the act of and serve to bind the Trust and an action taken by the
Institutional Trustee on behalf of the Trust in accordance with its powers shall
constitute the act of and serve to bind the Trust.  In dealing with the Trustees
acting on behalf of the Trust, no person shall be required to inquire into the
authority of the Trustees to bind the Trust.  Persons dealing with the Trust are
entitled to rely conclusively on the power and authority of the Trustees as set
forth in this Declaration.

     (b) Except as expressly set forth in this Declaration and except if a
meeting of the Regular Trustees is called with respect to any matter over which
the Regular Trustees have power to act, any power of the Regular Trustees may be
exercised by, or with the consent of, any one such Regular Trustee.

     (c) Unless otherwise determined by the Regular Trustees, and except as
otherwise required by the Business Trust Act or applicable law, any Regular
Trustee is authorized to execute on behalf of the Trust any documents which the
Regular Trustees have the power and authority to cause the Trust to execute
pursuant to Section 3.6, provided, that the registration statement referred to
in Section 3.6, including any amendments thereto, shall, subject to Section
3.4(d), be signed by all of the Regular Trustees; and

     (d) A Regular Trustee may, by power of attorney consistent with applicable
law, delegate to any other natural person over the age of 21 his or her power
for the purposes of executing any documents which the Regular Trustees have
power and authority to cause the Trust to execute pursuant to Section 3.6.

     SECTION 3.5.  Title to Property of the Trust.

     Except as provided in Section 3.8 with respect to the Debentures and the
Institutional Trustee Account or as otherwise provided in this Declaration,
legal title to all assets of the Trust shall be vested in the Trust.  The
Holders of Securities shall not have legal title to any part of the assets of
the Trust, but shall have an undivided beneficial interest in the assets of the
Trust.

     SECTION 3.6.  Powers and Duties of the Regular Trustees.

     The Regular Trustees shall have the exclusive power, duty and authority to
cause the Trust to engage in the following activities:

     (a) to issue and sell the Securities in accordance with this Declaration;
provided, however, that the Trust may issue no more than one series of
Convertible Preferred Securities and no more than one series of Common
Securities, and provided further, that there shall be no interests in the Trust
other than the Securities, and the issuance of Securities shall be limited to

                                       13
<PAGE>
 
a simultaneous issuance of both Convertible Preferred Securities and Common
Securities on the Closing Date and Option Closing Date, if any;

     (b) in connection with the issue and sale of the Securities, at the
direction of the Sponsor, to:

         (i) prepare and execute, if necessary, an offering memorandum (the
     "Offering Memorandum") in preliminary and final form prepared by the
     Sponsor, in relation to the offering and sale of Convertible Preferred
     Securities to qualified institutional buyers in reliance on Rule 144A under
     the Securities Act, to institutional "accredited investors" (as defined in
     Rule 501(a)(1), (2), (3) or (7) under the Securities Act) and outside the
     United States to non-U.S. persons in offshore transactions in reliance on
     Regulation S under the Securities Act and to execute and file with the
     Commission, at such time as determined by the Sponsor, a registration
     statement on Form S-3 prepared by the Sponsor, including any amendments
     thereto in relation to the Convertible Preferred Securities;

        (ii) execute and file an application, prepared by the Sponsor, to the
     Private Offerings, Resale and Trading through Automated Linkages ("PORTAL")
     Market and, at such time as determined by the Sponsor, to the New York
     Stock Exchange or any other national stock exchange or the Nasdaq Stock
     Market's National Market for listing or quotation of the Preferred
     Securities;

       (iii) execute and deliver letters, documents, or instruments with The
     Depository Trust Company relating to the Convertible Preferred Securities;

        (iv) execute and file with the Commission, at such time as determined
     by the Sponsor, a registration statement on Form 8-A, including any
     amendments thereto, prepared by the Sponsor relating to the registration of
     the Convertible Preferred Securities under Section 12(b) of the Exchange
     Act;

         (v) execute and enter into the Placement Agreement, Registration
     Rights Agreements and other related agreements providing for the sale of
     the Securities;

        (vi) execute and file any documents prepared by the Sponsor, or take any
     acts as determined by the Sponsor to be necessary in order to qualify or
     register all or part of the Convertible Preferred Securities in any State
     in which the Sponsor has determined to qualify or register such Convertible
     Preferred Securities for sale or resale, as the case may be; and

       (vii) take all actions and perform such duties as may be required of
     the Regular Trustees to open checking, deposit or similar banking accounts
     as may be necessary in connection with the issuance and sale of the
     Securities;

     (c) to acquire the Debentures with the proceeds of the sale of the
Convertible Preferred Securities and the Common Securities; provided, however,
that the Regular Trustees shall cause legal title to the Debentures to be held
of record in the name of the Institutional 

                                       14
<PAGE>
 
Trustee for the benefit of the Holders of the Convertible Preferred Securities
and the Holders of Common Securities;

     (d) to give the Sponsor and the Institutional Trustee prompt written notice
of the occurrence of a Special Event; provided that the Regular Trustees shall
consult with the Sponsor and the Institutional Trustee before taking or
refraining from taking any Ministerial Action in relation to a Special Event;

     (e) to establish a record date with respect to all actions to be taken
hereunder that require a record date be established, including and with respect
to, for the purposes of (S)316 (c) of the Trust Indenture Act, Distributions,
voting rights, redemptions and exchanges, and to issue relevant notices to the
Holders of Convertible Preferred Securities and Holders of Common Securities as
to such actions and applicable record dates;

     (f) to take all actions and perform such duties as may be required of the
Regular Trustees pursuant to the terms of the Securities;

     (g) to bring or defend, pay, collect, compromise, arbitrate, resort to
legal action, or otherwise adjust claims or demands of or against the Trust
("Legal Action"), unless pursuant to Section 3.8(e), the Institutional Trustee
has the exclusive power to bring such Legal Action;

     (h) to employ or otherwise engage employees and agents (who may be
designated as officers with titles) and managers, contractors, advisors and
consultants, and pay reasonable compensation for such services;

     (i) to cause the Trust to comply with the Trust's obligations under the
Trust Indenture Act;

     (j) to give the certificate required by (S) 314(a)(4) of the Trust
Indenture Act to the Institutional Trustee, which certificate may be executed by
any Regular Trustee;

     (k) to incur expenses that are necessary or incidental to carry out any of
the purposes of the Trust;

     (l) to act as, or appoint another Person to act as, registrar, transfer
agent, Paying Agent and Conversion Agent for the Securities;

     (m) to give prompt written notice to the Holders of the Securities of any
notice received from the Debenture Issuer of its election to defer payments of
interest on the Debentures by extending the interest payment period under the
Indenture;

     (n) to execute all documents or instruments, perform all duties and powers,
and do all things for and on behalf of the Trust in all matters necessary or
incidental to the foregoing;

     (o) to take all action that may be necessary or appropriate for the
preservation and the continuation of the Trust's valid existence, rights,
franchises and privileges as a statutory 

                                       15
<PAGE>
 
business trust under the laws of the State of Delaware and of each other
jurisdiction in which such existence is necessary to protect the limited
liability of the Holders of the Convertible Preferred Securities or to enable
the Trust to effect the purposes for which the Trust was created;

     (p) to take any action, not inconsistent with this Declaration or with
applicable law, that the Regular Trustees determine in their discretion to be
necessary or desirable in carrying out the activities of the Trust as set out in
this Section 3.6, including, but not limited to:

         (i) causing the Trust not to be deemed to be an Investment Company
     required to be registered under the Investment Company Act;

        (ii) causing the Trust to be classified for United States federal income
     tax purposes as a grantor trust; and

       (iii) cooperating with the Debenture Issuer to ensure that the Debentures
     will be treated as indebtedness of the Debenture Issuer for United States
     federal income tax purposes,

provided that such action does not adversely affect the interests of Holders or
vary the terms of the Convertible Preferred Securities;

     (q) to take all action necessary to cause all applicable tax returns and
tax information reports that are required to be filed with respect to the Trust
to be duly prepared and filed by the Regular Trustees, on behalf of the Trust;

     (r) to take all actions and perform such duties as may be required of the
Regular Trustees pursuant to Section 11.2 herein; and

     (s) to the extent provided in this Declaration, the winding up of the
affairs of and liquidation of the Trust and the preparation, execution and
filing of the Certificate of Cancellation with the Secretary of State of the
State of Delaware.

     The Regular Trustees must exercise the powers set forth in this Section 3.6
in a manner that is consistent with the purposes and functions of the Trust set
out in Section 3.3, and the Regular Trustees shall not take any action that is
inconsistent with the purposes and functions of the Trust set forth in Section
3.3.

     Subject to this Section 3.6, the Regular Trustees shall have none of the
powers or the authority of the Institutional Trustee set forth in Section 3.8.

     Any expenses incurred by the Regular Trustees pursuant to this Section 3.6
shall be reimbursed by the Sponsor.

     The Trust initially appoints the Institutional Trustee as transfer agent
and registrar for the Convertible Preferred Securities.

                                       16
<PAGE>
 
     SECTION 3.7.  Prohibition of Actions by the Trust and the Trustees.

     (a) The Trust shall not, and the Trustees (including the Institutional
Trustee) shall cause the Trust not to engage in any activity other than as
required or authorized by this Declaration.  In particular the Trust shall not
and the Trustees (including the Institutional Trustee) shall cause the Trust not
to:

         (i) invest any proceeds received by the Trust from holding the
     Debentures, but shall distribute all such proceeds to Holders of Securities
     pursuant to the terms of this Declaration and of the Securities;

        (ii) acquire any assets other than as expressly provided herein;

       (iii) possess Trust property for other than a Trust purpose;

        (iv) make any loans or incur any indebtedness other than loans
     represented by the Debentures;

        (v) possess any power or otherwise act in such a way as to vary the
     Trust assets or the terms of the Securities in any way whatsoever except as
     permitted by the terms of this Declaration;

       (vi) issue any securities or other evidences of beneficial ownership of,
     or beneficial interest in, the Trust other than the Securities; or

      (vii) other than as provided in this Declaration or Annex I hereto, (A)
     direct the time, method and place of exercising any trust or power
     conferred upon the Debenture Trustee with respect to the Debentures, (B)
     waive any past default that is not waivable under the Indenture, (C)
     exercise any right to rescind or annul any declaration that the principal
     of all the Debentures shall be due and payable, or (D) consent to any
     amendment, modification or termination of the Indenture or the Debentures
     where such consent shall be required unless the Trust shall have received
     an opinion of counsel to the effect that such modification will not cause
     more than an insubstantial risk that (x) the Trust will be deemed an
     Investment Company required to be registered under the Investment Company
     Act or (y) the Trust will not be classified as a grantor trust for United
     States federal income tax purposes.

     SECTION 3.8.  Powers and Duties of the Institutional Trustee.

     (a) The legal title to the Debentures shall be owned by and held of record
in the name of the Institutional Trustee in trust for the benefit of the Trust
and the Holders of the Securities.  The right, title and interest of the
Institutional Trustee to the Debentures shall vest automatically in each Person
who may hereafter be appointed as Institutional Trustee in accordance with
Section 5.6. Such vesting and cessation of title shall be effective whether or
not conveyancing documents with regard to the Debentures have been executed and
delivered.

                                       17
<PAGE>
 
     (b) The Institutional Trustee shall not transfer its right, title and
interest in the Debentures to the Regular Trustees or to the Delaware Trustee
(if the Institutional Trustee does not also act as Delaware Trustee).

     (c) The Institutional Trustee shall:

         (i) establish and maintain a segregated non-interest bearing trust
     account (the "Institutional Trustee Account") in the name of and under the
     exclusive control of the Institutional Trustee on behalf of the Holders of
     the Securities and, upon the receipt of payments of funds made in respect
     of the Debentures held by the Institutional Trustee, deposit such funds
     into the Institutional Trustee Account and make payments to the Holders of
     the Convertible Preferred Securities and Holders of the Common Securities
     from the Institutional Trustee Account in accordance with Section 6.1.
     Funds in the Institutional Trustee Account shall be held uninvested until
     disbursed in accordance with this Declaration. The Institutional Trustee
     Account shall be an account that is maintained with a banking institution
     the rating on whose long-term unsecured indebtedness is at least equal to
     the rating assigned to the Convertible Preferred Securities (or, if the
     Convertible Preferred Securities are not rated, the rating assigned to
     McKesson's senior debt) by a "nationally recognized statistical rating
     organization," as that term is defined for purposes of Rule 436(g)(2) under
     the Securities Act;

        (ii) engage in such ministerial activities as shall be necessary or
     appropriate to effect the redemption of the Convertible Preferred
     Securities and the Common Securities to the extent the Debentures are
     redeemed or mature;

       (iii) engage in such ministerial activities as shall be necessary or
     appropriate to effect the distribution of the Trust Property in accordance
     with the terms of this Declaration; and

        (iv) to the extent provided for in this Declaration, take such
     ministerial actions necessary in connection with the winding up of the
     affairs of and liquidation of the Trust and the preparation, execution and
     filing of the Certificate of Cancellation with the Secretary of State of
     the State of Delaware.

     (d) The Institutional Trustee shall take all actions and perform such
duties as may be specifically required of the Institutional Trustee pursuant to
the terms of the Securities.

     (e) The Institutional Trustee shall take any Legal Action which arises out
of or in connection with, an Event of Default of which a Responsible Officer of
the Institutional Trustee has actual knowledge, or the Institutional Trustee's
duties and obligations under this Declaration or the Trust Indenture Act;
provided however, that if a Declaration Event of Default has occurred and is
continuing and such event is attributable to the failure of the Debenture Issuer
to pay interest or principal on the Debentures on the date such interest or
principal is otherwise payable (or in the case of redemption, on the redemption
date), then a Holder of Convertible Preferred Securities may directly institute
a proceeding for enforcement of payment to such Holder of the principal of or
interest on the Debentures having a principal amount equal to the 

                                       18
<PAGE>
 
aggregate liquidation amount of the Convertible Preferred Securities of such
Holder (a "Direct Action") on or after the respective due date specified in the
Debentures and provided, further, that if the Institutional Trustee fails to
enforce its rights under the Debentures, any Holder of Convertible Preferred
Securities may institute a legal proceeding against any person to enforce the
Institutional Trustee's rights under the Debentures. In connection with such
Direct Action, the rights of the Holders of the Common Securities will be
subrogated to the rights of such Holder of Convertible Preferred Securities to
the extent of any payment made by the Debenture Issuer to such Holder of
Convertible Preferred Securities in such Direct Action. Except as provided in
the preceding sentences, the Holders of Convertible Preferred Securities will
not be able to exercise directly any other remedy available to the holders of
the Debentures.

     (f) The Institutional Trustee shall continue to serve as a Trustee until
either:

         (i) the Trust has been completely liquidated and the proceeds of the
     liquidation distributed to the Holders of Securities pursuant to the terms
     of the Securities; or

        (ii) a Successor Institutional Trustee has been appointed and has
     accepted that appointment in accordance with Section 5.6.

     (g) The Institutional Trustee shall have the legal power to exercise all of
the rights, powers and privileges of a holder of Debentures under the Indenture
and, if an Event of Default actually known to a Responsible Officer of the
Institutional Trustee occurs and is continuing, the Institutional Trustee shall,
for the benefit of Holders of the Securities, enforce its rights as holder of
the Debentures subject to the rights of the Holders pursuant to the terms of
such Securities.

     (h) The Institutional Trustee may authorize one or more Persons (each, a
"Paying Agent") to pay Distributions, redemption payments or Liquidation
Distributions on behalf of the Trust with respect to all Securities and any such
Paying Agent shall comply with (S) 317(b) of the Trust Indenture Act.  Any
Paying Agent may be removed by the Institutional Trustee at any time and a
successor Paying Agent or additional Paying Agents may be appointed at any time
by the Institutional Trustee.

     (i) Subject to this Section 3.8, the Institutional Trustee shall have none
of the duties, liabilities, powers or the authority of the Regular Trustees set
forth in Section 3.6.

     The Institutional Trustee must exercise the powers set forth in this
Section 3.8 in a manner that is consistent with the purposes and functions of
the Trust set out in Section 3.3, and the Institutional Trustee shall not take
any action that is inconsistent with the purposes and functions of the Trust set
out in Section 3.3.

     SECTION 3.9.  Certain Duties and Responsibilities of the Institutional
Trustee.

     (a) The Institutional Trustee, before the occurrence of any Event of
Default and after the curing of all Events of Default that may have occurred,
shall undertake to perform only such duties as are specifically set forth in
this Declaration and no implied covenants shall be read into 

                                       19
<PAGE>
 
this Declaration against the Institutional Trustee. In case an Event of Default
has occurred (that has not been cured or waived pursuant to Section 2.6) of
which a Responsible Officer of the Institutional Trustee has actual knowledge,
the Institutional Trustee shall exercise such of the rights and powers vested in
it by this Declaration, and use the same degree of care and skill in their
exercise, as a prudent person would exercise or use under the circumstances in
the conduct of his or her own affairs.

     (b) No provision of this Declaration shall be construed to relieve the
Institutional Trustee from liability for its own negligent action, its own
negligent failure to act, or its own willful misconduct, except that:

         (i) prior to the occurrence of an Event of Default and after the curing
     or waiving of all such Events of Default that may have occurred:

               (A) the duties and obligations of the Institutional Trustee shall
         be determined solely by the express provisions of this Declaration and
         the Institutional Trustee shall not be liable except for the
         performance of such duties and obligations as are specifically set
         forth in this Declaration, and no implied covenants or obligations
         shall be read into this Declaration against the Institutional Trustee;
         and

               (B) in the absence of bad faith on the part of the Institutional
         Trustee, the Institutional Trustee may conclusively rely, as to the
         truth of the statements and the correctness of the opinions expressed
         therein, upon any certificates or opinions furnished to the
         Institutional Trustee and conforming to the requirements of this
         Declaration; but in the case of any such certificates or opinions that
         by any provision hereof are specifically required to be furnished to
         the Institutional Trustee, the Institutional Trustee shall be under a
         duty to examine the same to determine whether or not they conform to
         the requirements of this Declaration;

        (ii) the Institutional Trustee shall not be liable for any error of
     judgment made in good faith by a Responsible Officer of the Institutional
     Trustee, unless it shall be proved that the Institutional Trustee was
     negligent in ascertaining the pertinent facts;

       (iii) the Institutional Trustee shall not be liable with respect to any
     action taken or omitted to be taken by it in good faith in accordance with
     the direction of the Holders of not less than a Majority in liquidation
     amount of the Securities relating to the time, method and place of
     conducting any proceeding for any remedy available to the Institutional
     Trustee, or exercising any trust or power conferred upon the Institutional
     Trustee under this Declaration;

        (iv) no provision of this Declaration shall require the Institutional
     Trustee to expend or risk its own funds or otherwise incur personal
     financial liability in the performance of any of its duties or in the
     exercise of any of its rights or powers, if it shall have reasonable
     grounds for believing that the repayment of such funds or liability is not
     reasonably assured to it under the terms of this Declaration or indemnity

                                       20
<PAGE>
 
     reasonably satisfactory to the Institutional Trustee against such risk or
     liability is not reasonably assured to it;

          (v)  the Institutional Trustee's sole duty with respect to the
     custody, safe keeping and physical preservation of the Debentures and the
     Institutional Trustee Account shall be to deal with such property in a
     similar manner as the Institutional Trustee deals with similar property for
     its own account, subject to the protections and limitations on liability
     afforded to the Institutional Trustee under this Declaration and the Trust
     Indenture Act;

         (vi)  the Institutional Trustee shall have no duty or liability for
     or with respect to the value, genuineness, existence or sufficiency of the
     Debentures or the payment of any taxes or assessments levied thereon or in
     connection therewith;

        (vii)  the Institutional Trustee shall not be liable for any interest
     on any money received by it except as it may otherwise agree in writing
     with the Sponsor.  Money held by the Institutional Trustee need not be
     segregated from other funds held by it except in relation to the
     Institutional Trustee Account maintained by the Institutional Trustee
     pursuant to Section 3.8(c)(i) and except to the extent otherwise required
     by law; and

       (viii)  the Institutional Trustee shall not be responsible for monitoring
     the compliance by the Regular Trustees or the Sponsor with their respective
     duties under this Declaration, nor shall the Institutional Trustee be
     liable for any default or misconduct of the Regular Trustees or the
     Sponsor.

     SECTION 3.10.  Certain Rights of Institutional Trustee.

     (a)  Subject to the provisions of Section 3.9:

          (i)  the Institutional Trustee may conclusively rely and shall be
     fully protected in acting or refraining from acting upon any resolution,
     certificate, statement, instrument, opinion, report, notice, request,
     direction, consent, order, bond, debenture, note, other evidence of
     indebtedness or other paper or document believed by it to be genuine and to
     have been signed, sent or presented by the proper party or parties;

         (ii)  any direction or act of the Sponsor or the Regular Trustees
     contemplated by this Declaration shall be sufficiently evidenced by an
     Officers' Certificate;

        (iii)  whenever in the administration of this Declaration, the
     Institutional Trustee shall deem it desirable that a matter be proved or
     established before taking, suffering or omitting any action hereunder, the
     Institutional Trustee (unless other evidence is herein specifically
     prescribed) may, in the absence of bad faith on its part, request and
     conclusively rely upon an Officers' Certificate which, upon receipt of such
     request, shall be promptly delivered by the Sponsor or the Regular
     Trustees;

                                       21
<PAGE>
 
         (iv)  the Institutional Trustee shall have no duty to see to any
     recording, filing or registration of any instrument (including any
     financing or continuation statement or any filing under tax or securities
     laws) or any rerecording, refiling or registration thereof;

          (v)  the Institutional Trustee may consult with counsel of its
     selection or other experts and the advice or opinion of such counsel and
     experts with respect to legal matters or advice within the scope of such
     experts' area of expertise shall be full and complete authorization and
     protection in respect of any action taken, suffered or omitted by it
     hereunder in good faith and in accordance with such advice or opinion.
     Such counsel may be counsel to the Sponsor or any of its Affiliates, and
     may include any of its employees.  The Institutional Trustee shall have the
     right at any time to seek instructions concerning the administration of
     this Declaration from any court of competent jurisdiction;

         (vi)  the Institutional Trustee shall be under no obligation to
     exercise any of the rights or powers vested in it by this Declaration at
     the request or direction of any Holder, unless such Holder shall have
     provided to the Institutional Trustee security and indemnity, reasonably
     satisfactory to the Institutional Trustee, against the costs, expenses
     (including attorneys' fees and expenses and the expenses of the
     Institutional Trustee's agents, nominees or custodians) and liabilities
     that might be incurred by it in complying with such request or direction,
     including such reasonable advances as may be requested by the Institutional
     Trustee provided, that, nothing contained in this Section 3.10(a)(vi) shall
     be taken to (a) require the Holders of Convertible Preferred Securities to
     offer such indemnity in the event such Holders direct the Institutional
     Trustee to take any action it is empowered to take under this Declaration
     following an Event of Default or (b) relieve the Institutional Trustee,
     upon the occurrence of an Event of Default, of its obligation to exercise
     the rights and powers vested in it by this Declaration;

        (vii)  the Institutional Trustee shall not be bound to make any
     investigation into the facts or matters stated in any resolution,
     certificate, statement, instrument, opinion, report, notice, request,
     direction, consent, order, bond, debenture, note, other evidence of
     indebtedness or other paper or document, but the Institutional Trustee, in
     its discretion, may make such further inquiry or investigation into such
     facts or matters as it may see fit;

       (viii)  the Institutional Trustee may execute any of the trusts or
     powers hereunder or perform any duties hereunder either directly or by or
     through agents, custodians, nominees or attorneys and the Institutional
     Trustee shall not be responsible for any misconduct or negligence on the
     part of any agent or attorney appointed with due care by it hereunder;

         (ix)  any action taken by the Institutional Trustee or its agents
     hereunder shall bind the Trust and the Holders of the Securities, and the
     signature of the Institutional Trustee or its agents alone shall be
     sufficient and effective to perform any such action and no third party
     shall be required to inquire as to the authority of the Institutional
     Trustee to so act or as to its compliance with any of the terms and
     provisions of this 

                                       22
<PAGE>
 
     Declaration, both of which shall be conclusively evidenced by the
     Institutional Trustee's or its agent's taking such action;

          (x)  whenever in the administration of this Declaration the
     Institutional Trustee shall deem it desirable to receive written
     instructions with respect to enforcing any remedy or right or taking any
     other action hereunder, the Institutional Trustee (i) may request written
     instructions from the Holders of the Securities which instructions may only
     be given by the Holders of the same proportion in liquidation amount of the
     Securities as would be entitled to direct the Institutional Trustee under
     the terms of the Securities in respect of such remedy, right or action,
     (ii) may refrain from enforcing such remedy or right or taking such other
     action until such instructions are received, and (iii) shall be protected
     in conclusively relying on or acting in or accordance with such
     instructions;

         (xi)  except as otherwise expressly provided by this Declaration,
     the Institutional Trustee shall not be under any obligation to take any
     action that is discretionary under the provisions of this Declaration; and

        (xii)  the Institutional Trustee shall not be liable for any action
     taken, suffered, or omitted to be taken by it in good faith and reasonably
     believed by it to be authorized or within the discretion or rights or
     powers conferred upon it by this Declaration.

     (b)   No provision of this Declaration shall be deemed to impose any duty
or obligation on the Institutional Trustee to perform any act or acts or
exercise any right, power, duty or obligation conferred or imposed on it, in any
jurisdiction in which it shall be illegal, or in which the Institutional Trustee
shall be unqualified or incompetent in accordance with applicable law, to
perform any such act or acts, or to exercise any such right, power, duty or
obligation. No permissive power or authority available to the Institutional
Trustee shall be construed to be a duty.

     SECTION 3.11.  Delaware Trustee.

     Notwithstanding any other provision of this Declaration other than Section
5.2, the Delaware Trustee shall not be entitled to exercise any powers, nor
shall the Delaware Trustee have any of the duties and responsibilities of the
Regular Trustees, the Institutional Trustee or the Trustees generally (except as
may be required under the Business Trust Act) described in this Declaration.
Except as set forth in Section 5.2, the Delaware Trustee shall be a Trustee for
the sole and limited purpose of fulfilling the requirements of (S) 3807 of the
Business Trust Act.

     SECTION 3.12.  Execution of Documents.

     Except as otherwise required by the Business Trust Act, any Regular Trustee
is authorized to execute on behalf of the Trust any documents that the Regular
Trustees have the power and authority to execute pursuant to Section 3.6;
provided that, the registration statement referred to in Section 3.6(b)(i),
including any amendments thereto, shall, subject to Section 3.4(d), be signed by
all of the Regular Trustees.

                                       23
<PAGE>
 
     SECTION 3.13.  Not Responsible for Recitals or Issuance of Securities.

     The recitals contained in this Declaration and the Securities shall be
taken as the statements of the Sponsor, and the Trustees do not assume any
responsibility for their correctness.  The Trustees make no representations as
to the value or condition of the property of the Trust or any part thereof.  The
Trustees make no representations as to the validity or sufficiency of this
Declaration or the Securities.

     SECTION 3.14.  Duration of Trust.

     The Trust, unless terminated pursuant to the provisions of Article VIII
hereof, shall have existence for thirty-five (35) years from June 1, 1997.

     SECTION 3.15.  Mergers.

     (a)  The Trust may not consolidate, amalgamate, merge with or into, or be
replaced by, or convey, transfer or lease its properties and assets as an
entirety or substantially as an entirety to any corporation or other body,
except as described in Section 3.15(b) and (c).

     (b)  The Trust may, with the consent of the Regular Trustees or, if there
are more than two, a majority of the Regular Trustees and without the consent of
the Holders of the Securities, the Delaware Trustee or the Institutional
Trustee, consolidate, amalgamate, merge with or into, or be replaced by a trust
organized as such under the laws of any State; provided that

          (i)  such successor entity (the "Successor Entity") either:

               (A)  expressly assumes all of the obligations of the Trust under
           the Securities; or

               (B)  substitutes for the Convertible Preferred Securities other
           securities having substantially the same terms as the Convertible
           Preferred Securities (the "Successor Securities") so long as the
           Successor Securities rank the same as the Convertible Preferred
           Securities rank with respect to Distributions and payments upon
           liquidation, redemption and otherwise;

         (ii)  the Debenture Issuer expressly acknowledges a trustee of the
     Successor Entity that possesses the same powers and duties as the
     Institutional Trustee as the Holder of the Debentures;

        (iii)  such merger, consolidation, amalgamation or replacement does
     not cause the Convertible Preferred Securities (including any Successor
     Securities) to be downgraded by any nationally recognized statistical
     rating organization;

         (iv)  such merger, consolidation, amalgamation or replacement does
     not adversely affect the rights, preferences and privileges of the Holders
     of the Securities 

                                       24
<PAGE>
 
     (including any Successor Securities) in any material respect (other than
     with respect to any dilution of the Holders' interest in the Successor
     Entity);

          (v)  such Successor Entity has a purpose identical to that of the
     Trust;

         (vi)  prior to such merger, consolidation, amalgamation or
     replacement, the Sponsor has received an opinion of nationally recognized
     independent counsel to the Trust experienced in such matters to the effect
     that:

               (A)  such merger, consolidation, amalgamation or replacement does
           not adversely affect the rights, preferences and privileges of the
           Holders of the Securities (including any Successor Securities) in any
           material respect (other than with respect to any dilution of the
           Holders' interest in the Successor Entity);

               (B)  following such merger, consolidation, amalgamation or
           replacement, neither the Trust nor the Successor Entity will be
           required to register as an Investment Company; and

               (C)  following such merger, consolidation, amalgamation or
           replacement, the Trust (or such Successor Entity) will continue to be
           classified as a grantor trust for United States federal income tax
           purposes; and

        (vii)  the Sponsor guarantees the obligations of the Successor Entity
     under the Successor Securities at least to the extent provided by the
     Securities Guarantees.

     (c)   Notwithstanding Section 3.15(b), the Trust shall not, except with the
consent of Holders of 100% in liquidation amount of the Securities, consolidate,
amalgamate, merge with or into, or be replaced by any other entity or permit any
other entity to consolidate, amalgamate, merge with or into, or replace it, if
such consolidation, amalgamation, merger or replacement would cause the Trust or
the Successor Entity to be classified as other than a grantor trust for United
States federal income tax purposes.


                                   ARTICLE IV

                                    SPONSOR

     SECTION 4.1.   Sponsor's Purchase of Common Securities.

     On the Closing Date the Sponsor will purchase all of the Common Securities
issued by the Trust, in an amount at least equal to 3% of the capital of the
Trust, at the same time as the Convertible Preferred Securities are sold.

                                       25
<PAGE>
 
     SECTION 4.2.   Responsibilities of the Sponsor.

     In connection with the issue and sale of the Convertible Preferred
Securities, the Sponsor shall have the exclusive right and responsibility to
engage in the following activities:

     (a)   prepare and execute, if necessary, the Offering Memorandum in
preliminary and final form, in relation to the offering and sale by the Trust of
Convertible Preferred Securities to qualified institutional buyers in reliance
on Rule 144A under the Securities Act, to institutional "accredited investors"
(as defined in Rule 501(a)(1),(2), (3) or (7) under the Securities Act) and
outside the United States to Non-U.S. persons in offshore transactions in
reliance on Regulation S under the Securities Act;

     (b)   to prepare for filing by the Trust with the Commission a registration
statement on Form S-3 in relation to the Securities, including any amendments
thereto;

     (c)   prepare for execution and filing by the Trust of an application,
prepared by the Sponsor, to the PORTAL Market and, at such time as determined by
the Sponsor, to the New York Stock Exchange or any other national stock exchange
or the Nasdaq Stock Market's National Market for listing or quotation of the
Convertible Preferred Securities;

     (d)   prepare for execution and filing by the Trust of documents, or
instruments to be delivered to The Depository Trust Company relating to the
Convertible Preferred Securities;

     (e)   prepare for execution and filing by the Trust of a registration
statement on Form 8-A, including any amendments thereto, prepared by the Sponsor
relating to the registration of the Convertible Preferred Securities under
Section 12(b) of the Exchange Act;

     (f)   to determine the States in which to take appropriate action to
qualify or register for sale all or part of the Convertible Preferred Securities
and to do any and all such acts, other than actions which must be taken by the
Trust, and advise the Trust of actions it must take, and prepare for execution
and filing any documents to be executed and filed by the Trust, as the Sponsor
deems necessary or advisable in order to comply with the applicable laws of any
such States;

     (g)   to negotiate the terms of the Placement Agreement providing for the
sale of the Convertible Preferred Securities; and

     (h)   to negotiate the terms of the Registration Rights Agreements
providing for, among other things, the registration under the Securities Act of
resales from time to time of the Securities.

                                       26
<PAGE>
 
                                   ARTICLE V

                                   TRUSTEES

     SECTION 5.1.   Number of Trustees.

     The number of Trustees initially shall be five (5), and:

     (a)   at any time before the issuance of any Securities, the Sponsor may,
by written instrument, increase or decrease the number of Trustees; and

     (b)   after the issuance of any Securities, the number of Trustees may be
increased or decreased by vote of the Holders of a majority in liquidation
amount of the Common Securities voting as a class at a meeting of the Holders of
the Common Securities; provided, however, that the number of Trustees shall in
no event be less than two (2); provided further, that (i) one Trustee, in the
case of a natural person, shall be a person who is a resident of the State of
Delaware or that, if not a natural person, is an entity which has its principal
place of business in the State of Delaware (the "Delaware Trustee"); (ii) there
shall be at least one Trustee who is an employee or officer of, or is affiliated
with the Sponsor (a "Regular Trustee"); and (iii) one Trustee shall be the
Institutional Trustee, and such Trustee may also serve as Delaware Trustee if it
meets the applicable requirements.

     SECTION 5.2.   Delaware Trustee.

     If required by the Business Trust Act, one Trustee shall be:

     (a)   a natural person who is a resident of the State of Delaware; or

     (b)   if not a natural person, an entity which has its principal place of
business in the State of Delaware, and otherwise meets the requirements of
applicable law;

provided that, if the Institutional Trustee has its principal place of business
in the State of Delaware and otherwise meets the requirements of applicable law,
then the Institutional Trustee shall also be the Delaware Trustee and Section
3.11 shall have no application.

     The Initial Delaware Trustee shall be:  First Chicago Delaware Inc.

     SECTION 5.3.   Institutional Trustee; Eligibility.

     (a)   There shall at all times be one Trustee which shall act as
Institutional Trustee which shall:

          (i)  not be an Affiliate of the Sponsor; and

         (ii)  be a corporation organized and doing business under the laws
     of the United States of America or any State or Territory thereof or of the
     District of Columbia, or a

                                       27
<PAGE>
 
     corporation or Person permitted by the Commission to act as an
     institutional trustee under the Trust Indenture Act, authorized under such
     laws to exercise corporate trust powers, having a combined capital and
     surplus of at least 50 million U.S. dollars ($50,000,000), and subject to
     supervision or examination by federal, state, territorial or District of
     Columbia authority.  If such corporation publishes reports of condition at
     least annually, pursuant to law or to the requirements of the supervising
     or examining authority referred to above, then for the purposes of this
     Section 5.3(a)(ii), the combined capital and surplus of such corporation
     shall be deemed to be its combined capital and surplus as set forth in its
     most recent report of condition so published.

     (b)   If at any time the Institutional Trustee shall cease to be eligible
to so act under Section 5.3(a), the Institutional Trustee shall immediately
resign in the manner and with the effect set forth in Section 5.6(c).

     (c)   If the Institutional Trustee has or shall acquire any "conflicting
interest" within the meaning of (S) 310(b) of the Trust Indenture Act, the
Institutional Trustee and the Holder of the Common Securities (as if it were the
obligor referred to in (S) 310(b) of the Trust Indenture Act) shall in all
respects comply with the provisions of (S) 310(b) of the Trust Indenture Act.

     (d)   The Convertible Preferred Securities Guarantee shall be deemed to be
specifically described in this Declaration for purposes of clause (i) of the
first provision contained in Section 310(b) of the Trust Indenture Act.

     (e)   The initial Institutional Trustee shall be: The First National Bank
of Chicago.

     SECTION 5.4.   Certain Qualifications of Regular Trustees and Delaware
Trustee Generally.

     Each Regular Trustee and the Delaware Trustee (unless the Institutional
Trustee also acts as Delaware Trustee) shall be either a natural person who is
at least 21 years of age or a legal entity that shall act through one or more
Authorized Officers.

     SECTION 5.5.   Regular Trustees.

     The initial Regular Trustees shall be:

           William A. Armstrong
           Ivan D. Meyerson
           Nancy Miller

     (a)   Except as expressly set forth in this Declaration and except if a
meeting of the Regular Trustees is called with respect to any matter over which
the Regular Trustees have power to act, any power of the Regular Trustees may be
exercised by, or with the consent of, any one such Regular Trustee.

                                       28
<PAGE>
 
     (b)   Unless otherwise determined by the Regular Trustees, and except as
otherwise required by the Business Trust Act or applicable law, any Regular
Trustee is authorized to execute on behalf of the Trust any documents which the
Regular Trustees have the power and authority to cause the Trust to execute
pursuant to Section 3.6, provided, that, the registration statement referred to
in Section 3.6, including any amendments thereto, shall, subject to Section
3.4(d), be signed by all of the Regular Trustees; and

     SECTION 5.6.   Appointment, Removal and Resignation of Trustees.

     (a)   Subject to Section 5.6(b), Trustees may be appointed or removed
without cause at any time:

          (i)  until the issuance of any Securities, by written instrument
     executed by the Sponsor; and

         (ii)  after the issuance of any Securities, by vote of the Holders
     of a Majority in liquidation amount of the Common Securities voting as a
     class at a meeting of the Holders of the Common Securities.

     (b)  (i)  The Trustee that acts as Institutional Trustee shall not be
removed in accordance with Section 5.6(a) until a Successor Institutional
Trustee has been appointed and has accepted such appointment by written
instrument executed by such Successor Institutional Trustee and delivered to the
Regular Trustees and the Sponsor; and

         (ii)  the Trustee that acts as Delaware Trustee shall not be removed
     in accordance with Section 5.6(a) until a successor Trustee possessing the
     qualifications to act as Delaware Trustee under Sections 5.2 and 5.4 (a
     "Successor Delaware Trustee") has been appointed and has accepted such
     appointment by written instrument executed by such Successor Delaware
     Trustee and delivered to the Regular Trustees and the Sponsor.

     (c)   A Trustee appointed to office shall hold office until his successor
shall have been appointed or until his death, removal or resignation.  Any
Trustee may resign from office (without need for prior or subsequent accounting)
by an instrument in writing signed by the Trustee and delivered to the Sponsor
and the Trust, which resignation shall take effect upon such delivery or upon
such later date as is specified therein; provided, however, that:

          (i)  No such resignation of the Trustee that acts as the
     Institutional Trustee shall be effective:

                  (A)   until a Successor Institutional Trustee has been
           appointed and has accepted such appointment by instrument executed by
           such Successor Institutional Trustee and delivered to the Trust, the
           Sponsor and the resigning Institutional Trustee; or

                                       29
<PAGE>
 
                  (B)   until the assets of the Trust have been completely
           liquidated and the proceeds thereof distributed to the holders of the
           Securities; and

         (ii)  no such resignation of the Trustee that acts as the Delaware
     Trustee shall be effective until a Successor Delaware Trustee has been
     appointed and has accepted such appointment by instrument executed by such
     Successor Delaware Trustee and delivered to the Trust, the Sponsor and the
     resigning Delaware Trustee.

     (d)   the Holders of the Common Securities shall use their best efforts to
promptly appoint a Successor Delaware Trustee or Successor Institutional Trustee
as the case may be if the Institutional Trustee or the Delaware Trustee delivers
an instrument of resignation in accordance with this Section 5.6.

     (e)   If no Successor Institutional Trustee or Successor Delaware Trustee
shall have been appointed and accepted appointment as provided in this Section
5.6 within 60 days after delivery of an instrument of resignation or removal,
the Institutional Trustee or Delaware Trustee resigning or being removed, as
applicable, may petition any court of competent jurisdiction for appointment of
a Successor Institutional Trustee or Successor Delaware Trustee.  Such court may
thereupon, after prescribing such notice, if any, as it may deem proper and
prescribe, appoint a Successor Institutional Trustee or Successor Delaware
Trustee, as the case may be.

     (f) No Institutional Trustee or Delaware Trustee shall be liable for the
acts or omissions to act of any Successor Institutional Trustee or Successor
Delaware Trustee, as the case may be.

     SECTION 5.7.   Vacancies Among Trustees.

     If a Trustee ceases to hold office for any reason and the number of
Trustees is not reduced pursuant to Section 5.1, or if the number of Trustees is
increased pursuant to Section 5.1, a vacancy shall occur.  A resolution
certifying the existence of such vacancy by the Regular Trustees or, if there
are more than two, a majority of the Regular Trustees shall be conclusive
evidence of the existence of such vacancy.  The vacancy shall be filled with a
Trustee appointed in accordance with Section 5.6.

     SECTION 5.8.   Effect of Vacancies.

     The death, resignation, retirement, removal, bankruptcy, dissolution,
liquidation, incompetence or incapacity to perform the duties of a Trustee shall
not operate to annul the Trust. Whenever a vacancy in the number of Regular
Trustees shall occur, until such vacancy is filled by the appointment of a
Regular Trustee in accordance with Section 5.6, the Regular Trustees in office,
regardless of their number, shall have all the powers granted to the Regular
Trustees and shall discharge all the duties imposed upon the Regular Trustees by
this Declaration.

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<PAGE>
 
     SECTION 5.9.   Meetings.

     If there is more than one Regular Trustee, meetings of the Regular Trustees
shall be held from time to time upon the call of any Regular Trustee. Regular
meetings of the Regular Trustees may be held at a time and place fixed by
resolution of the Regular Trustees. Notice of any in-person meetings of the
Regular Trustees shall be hand delivered or otherwise delivered in writing
(including by facsimile, with a hard copy by overnight courier) not less than 48
hours before such meeting. Notice of any telephonic meetings of the Regular
Trustee or any committee thereof shall be hand delivered or otherwise delivered
in writing (including by facsimile, with a hard copy by overnight courier) not
less than 24 hours before a meeting. Notices shall contain a brief statement of
the time, place and anticipated purposes of the meeting. The presence (whether
in person or by telephone) of a Regular Trustee at a meeting shall constitute a
waiver of notice of such meeting except where a Regular Trustee attends a
meeting for the express purpose of objecting to the transaction of any activity
on the ground that the meeting has not been lawfully called or convened. Unless
provided otherwise in this Declaration, any action of the Regular Trustees may
be taken at a meeting by vote of a majority of the Regular Trustees present
(whether in person or by telephone) and eligible to vote with respect to such
matter, provided that a Quorum is present, or without a meeting by the unanimous
written consent of the Regular Trustees. In the event there is only one Regular
Trustee, any and all action of such Regular Trustee shall be evidenced by a
written consent of such Regular Trustee.

     SECTION 5.10.  Delegation of Power.

     A Regular Trustee may, by power of attorney consistent with applicable law,
delegate to any other natural person over the age of 21 his or her power for the
purposes of executing any documents contemplated in Section 3.6, including any
registration statement or amendment thereto filed with the Commission, or making
any other governmental filing.

     The Regular Trustees shall have power to delegate from time to time to such
of their number or to officers of the Trust the doing of such things and the
execution of such instruments either in the name of the Trust or the names of
the Regular Trustees or otherwise as the Regular Trustees may deem expedient, to
the extent such delegation is not prohibited by applicable law or contrary to
the provisions of the Trust, as set forth herein.

     SECTION 5.11.  Merger, Conversion, Consolidation or Succession to Business.

     Any corporation into which the Institutional Trustee or the Delaware
Trustee, as the case may be, may be merged or converted or with which either may
be consolidated, or any corporation resulting from any merger, conversion or
consolidation to which the Institutional Trustee or the Delaware Trustee, as the
case may be, shall be a party, or any corporation succeeding to all or
substantially all the corporate trust business of the Institutional Trustee or
the Delaware Trustee, as the case may be, shall be the successor of the
Institutional Trustee or the Delaware Trustee, as the case may be, hereunder,
provided such corporation shall be otherwise qualified and eligible under this
Article, without the execution or filing of any paper or any further act on the
part of any of the parties hereto.

                                       31
<PAGE>
 
                                  ARTICLE VI

                                 DISTRIBUTIONS

     SECTION 6.1.   Distributions.

     Holders of Securities shall receive Distributions (as defined herein) in
accordance with the applicable terms of the relevant Holder's Securities.
Distributions shall be made on the Convertible Preferred Securities and the
Common Securities in accordance with the preferences set forth in their
respective terms.  If and to the extent that the Debenture Issuer makes a
payment of interest (including Compound Interest (as defined in the Indenture)
and Additional Sums (as defined in the Indenture)), premium and/or principal on
the Debentures held by the Institutional Trustee (the amount of any such payment
being a "Payment Amount"), the Institutional Trustee shall and is directed, to
the extent funds are available for that purpose, to make a distribution (a
"Distribution") of the Payment Amount to Holders.


                                  ARTICLE VII

                            ISSUANCE OF SECURITIES

     SECTION 7.1.   General Provisions Regarding Securities.

     (a)   The Regular Trustees shall on behalf of the Trust issue one class of
convertible preferred securities representing undivided beneficial interests in
the assets of the Trust having such terms as are set forth in Annex I (the
"Convertible Preferred Securities") and one class of convertible common
securities representing undivided beneficial interests in the assets of the
Trust having such terms as are set forth in Annex I (the "Common Securities").
The Trust shall issue no securities or other interests in the assets of the
Trust other than the Convertible Preferred Securities and the Common Securities.

     (b)   The consideration received by the Trust for the issuance of the
Securities shall  constitute a contribution to the capital of the Trust and
shall not constitute a loan to the Trust.

     (c)   Upon issuance of the Securities as provided in this Declaration, the
Securities so issued shall be deemed to be validly issued, fully paid and 
non-assessable.

     (d)   Every Person, by virtue of having become a Holder or a Convertible
Preferred Security Beneficial Owner in accordance with the terms of this
Declaration, shall be deemed to have expressly assented and agreed to the terms
of and shall be bound by this Declaration.

     SECTION 7.2.   Execution and Authentication.

     (a)   The Certificates shall be signed on behalf of the Trust by a Regular
Trustee.  In case any Regular Trustee of the Trust who shall have signed any of
the Securities shall cease 

                                       32
<PAGE>
 
to be such Regular Trustee before the Certificates so signed shall be delivered
by the Trust, such Certificates nevertheless may be delivered as though the
person who signed such Certificates had not ceased to be such Regular Trustee;
and any Certificate may be signed on behalf of the Trust by such persons who, at
the actual date of execution of such Security, shall be the Regular Trustees of
the Trust, although at the date of the execution and delivery of the Declaration
any such person was not such a Regular Trustee.

     (b)   One Regular Trustee shall sign the Convertible Preferred Securities
for the Trust by manual or facsimile signature. Unless otherwise determined by
the Trust, such signature shall, in the case of Common Securities, be a manual
signature.

     A Convertible Preferred Security shall not be valid until authenticated by
the manual signature of an authorized signatory of the Institutional Trustee.
The signature shall be conclusive evidence that the Convertible Preferred
Security has been authenticated under this Declaration.

     Upon a written order of the Trust signed by one Regular Trustee, the
Institutional Trustee shall authenticate the Convertible Preferred Securities
for original issue.

     The Institutional Trustee may appoint an authenticating agent acceptable to
the Trust to authenticate Convertible Preferred Securities.  An authenticating
agent may authenticate Convertible Preferred Securities whenever the
Institutional Trustee may do so.  Each reference in this Declaration to
authentication by the Institutional Trustee includes authentication by such
agent.  An authenticating agent has the same rights as the Institutional Trustee
to deal with the Company or an Affiliate.

     SECTION 7.3.   Form and Dating.

     The Convertible Preferred Securities and the Institutional Trustee's
certificate of authentication shall be substantially in the form of Exhibit A-1
and the Common Securities shall be substantially in the form of Exhibit A-2,
each of which is hereby incorporated in and expressly made a part of this
Declaration.  Certificates may be printed, lithographed or engraved or may be
produced in any other manner as is reasonably acceptable to the Regular
Trustees, as evidenced by their execution thereof.  The Securities may have
letters, numbers, notations, other marks of identification or designation or
other changes or additions thereto or deletions therefrom as may be required by
ordinary usage, custom or practice and such legends or endorsements required by
law, stock exchange rule and agreements to which the Trust is subject, if any
(provided that any such notation, legend or endorsement is in a form acceptable
to the Trust).  The Trust at the direction of the Sponsor shall furnish any such
legend not contained in Exhibit A-1 to the Institutional Trustee in writing.
Each Convertible Preferred Security Certificate shall be dated the date of its
authentication.  The terms and provisions of the Securities set forth in Annex I
and the forms of Securities set forth in Exhibits A-1 and A-2 are part of the
terms of this Declaration and, to the extent applicable, the Institutional
Trustee and the Sponsor, by their execution and delivery of this Declaration,
expressly agree to such terms and provisions and to be bound thereby.

                                       33
<PAGE>
 
     SECTION 7.4.   Paying Agent.  The Trust shall maintain in the Borough of
Manhattan, City of New York, State of New York, an office or agency where
Convertible Preferred Securities not held in book-entry only form may be
presented for payment ("Paying Agent").  The Trust shall maintain an office or
agency where Securities may be presented for conversion ("Conversion Agent").
The Trust may appoint the Paying Agent and the Conversion Agent and may appoint
one or more additional paying agents and one or more additional conversion
agents in such other locations as it shall determine.  The term "Paying Agent"
includes any additional paying agent and the term "Conversion Agent" includes
any additional conversion agent.  The Trust may change any Paying Agent or
Conversion Agent without prior notice to any Holder.  The Trust shall notify the
Institutional Trustee in writing of the name and address of any Agent not a
party to this Declaration.  If the Trust fails to appoint or maintain another
entity as Paying Agent or Conversion Agent, the Institutional Trustee shall act
as such.  The Trust or any of its Affiliates may act as Paying Agent or
Conversion Agent.  The Trust shall act as Paying Agent and Conversion Agent for
the Common Securities.

     The Trust initially appoints The First National Bank of Chicago, c/o First
Chicago Trust Company of New York, 14 Wall Street, 8th Floor - Window 2, New
York, NY 10005, Attention: Corporate Trust Administration as Paying Agent and
Conversion Agent for the Convertible Preferred Securities.


                                 ARTICLE VIII

                             TERMINATION OF TRUST

     SECTION 8.1.   Termination of Trust.

     (a)   The Trust shall terminate:

          (i)  upon the bankruptcy of the Sponsor or the Holder of the Common
     Securities;

         (ii)  upon the filing of a certificate of dissolution or its
     equivalent with respect to the Sponsor or the Holder of the Common
     Securities; the filing of a certificate of cancellation with respect to the
     Trust after having obtained the consent of at least a Majority in
     liquidation amount of the Securities voting together as a single class to
     file such certificate of cancellation; or the revocation of the Sponsor's
     charter or the charter of the Holder of the Common Securities and the
     expiration of 90 days after the date of revocation without a reinstatement
     thereof;

        (iii)  upon the entry of a decree of judicial dissolution of the
     Sponsor, the Trust or the Holder of the Common Securities;

         (iv)  when all of the Securities shall have been called for redemption
     and the amounts necessary for redemption thereof shall have been paid to
     the Holders in accordance with the terms of the Securities;

                                       34
<PAGE>
 
          (v)  upon the occurrence and continuation of a Special Event pursuant
     to which the Trust shall have been dissolved in accordance with the terms
     of the Securities and all of the Debentures held by the Institutional
     Trustee shall have been distributed to the Holders of Securities in
     exchange for all of the Securities;

         (vi)  upon the written direction to the Institutional Trustee from the
     Sponsor at any time to terminate the Trust and, after satisfaction of
     liabilities to creditors of the Trust as provided by applicable law, the
     distribution of Debentures to Holders in exchange for the Securities,
     subject to the Regular Trustees' receipt of an opinion of nationally
     recognized independent counsel experienced in such matters to the effect
     that the holders of the Convertible Preferred Securities will not recognize
     any income, gain or loss for United States federal income tax purposes as a
     result of the dissolution of the Trust and such distribution to Holders.

        (vii)  upon the distribution of the Sponsor's Common Stock to all
     Holders of Convertible Preferred Securities upon conversion of all
     outstanding Convertible Preferred Securities;

       (viii)  the expiration of the term of the Trust on June 1, 2032; or

           (ix) before the issuance of any Securities, with the consent of all
     of the Regular Trustees and the Sponsor.

     (b)   As soon as is practicable after the occurrence of an event referred
to in Section 8.1(a), the Trustees shall file a certificate of cancellation with
the Secretary of State of the State of Delaware.

     (c)   The provisions of Sections 3.9 and 3.10 and Article X shall survive
the termination of the Trust.


                                  ARTICLE IX

                             TRANSFER OF INTERESTS

     SECTION 9.1.   Transfer of Securities.

     (a)   Securities may only be transferred, in whole or in part, in
accordance with the terms and conditions set forth in this Declaration and in
the terms of the Securities. Any transfer or purported transfer of any Security
not made in accordance with this Declaration shall be null and void.

     (b)   Subject to this Article IX, Convertible Preferred Securities shall be
transferable.

     (c)   Subject to this Article IX, the Sponsor and any Related Party may
only transfer Common Securities to the Sponsor or a Related Party of the
Sponsor; provided that, any such 

                                       35
<PAGE>
 
transfer is subject to the condition precedent that the transferor obtain the
written opinion of nationally recognized independent counsel experienced in such
matters that such transfer would not cause more than an insubstantial risk that:

          (i)  the Trust would not be classified for United States federal
     income tax purposes as a grantor trust; and

         (ii)  the Trust would be an Investment Company required to register
     under the Investment Company Act or the transferee would become an
     Investment Company required to register under the Investment Company Act.

     (d)   Each Security that bears or is required to bear the legend set forth
in this Section 9.1(d) (a "Restricted Security") shall be subject to the
restrictions on transfer provided in the legend set forth in this Section
9.1(d), unless such restrictions on transfer shall be waived by the written
consent of the Regular Trustees, and the Holder of each Restricted Security, by
such securityholder's acceptance thereof, agrees to be bound by such
restrictions on transfer. As used in this Section 9.1(d) and in Section 9.1(e),
the term "transfer" encompasses any sale, pledge, transfer or other disposition
of any Restricted Security.

     Prior to the Transfer Restriction Termination Date, any certificate
evidencing a Security shall bear a legend in substantially the following form,
unless otherwise agreed by the Regular Trustees (with written notice thereof to
the Institutional Trustee):

     THE SECURITY EVIDENCED HEREBY HAS NOT BEEN REGISTERED UNDER THE U.S.
SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND, ACCORDINGLY, MAY
NOT BE OFFERED OR SOLD WITHIN THE UNITED STATES OR TO, OR FOR THE ACCOUNT OR
BENEFIT OF, U.S. PERSONS EXCEPT AS SET FORTH IN THE FOLLOWING SENTENCE. BY ITS
ACQUISITION HEREOF, THE HOLDER (1) REPRESENTS THAT (A) IT IS A "QUALIFIED
INSTITUTIONAL BUYER" (AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT) OR (B)
IT IS AN INSTITUTIONAL "ACCREDITED INVESTOR" (AS DEFINED IN RULE 501(A)(1), (2),
(3) OR (7) UNDER THE SECURITIES ACT) ("INSTITUTIONAL ACCREDITED INVESTOR") OR
(C) IT IS NOT A U.S. PERSON AND IS ACQUIRING THE SECURITY EVIDENCED HEREBY IN AN
OFFSHORE TRANSACTION, (2) AGREES THAT IT WILL NOT PRIOR TO THE EXPIRATION OF THE
HOLDING PERIOD APPLICABLE TO SALES OF THE SECURITY EVIDENCED HEREBY UNDER RULE
144(K) UNDER THE SECURITIES ACT (OR ANY SUCCESSOR PROVISION) RESELL OR OTHERWISE
TRANSFER THE SECURITY EVIDENCED HEREBY OR THE COMMON STOCK, ISSUABLE UPON 
CONVERSION OR EXCHANGE OF THIS SECURITY EXCEPT (A) TO McKESSON CORPORATION (THE
"COMPANY") OR ANY SUBSIDIARY THEREOF, (B) PURSUANT TO AN EFFECTIVE REGISTRATION
STATEMENT UNDER THE SECURITIES ACT, (C) TO A QUALIFIED INSTITUTIONAL BUYER IN
COMPLIANCE WITH RULE 144A UNDER THE SECURITIES ACT, (D) TO AN INSTITUTIONAL
ACCREDITED INVESTOR THAT, PRIOR TO SUCH TRANSFER, FURNISHES TO THE TRUSTEE FOR
THE CONVERTIBLE PREFERRED SECURITIES OR THE CONVERTIBLE DEBENTURES, AS THE CASE
MAY BE (OR, IF THIS CERTIFICATE EVIDENCES COMMON STOCK, THE TRANSFER

                                       36
<PAGE>
 
AGENT FOR THE COMMON STOCK), A SIGNED LETTER CONTAINING CERTAIN REPRESENTATIONS
AND AGREEMENTS RELATING TO THE RESTRICTIONS ON TRANSFER OF THE SECURITY
EVIDENCED HEREBY (THE FORM OF WHICH LETTER CAN BE OBTAINED FROM SUCH TRUSTEE OR
TRANSFER AGENT), (E) OUTSIDE THE UNITED STATES IN COMPLIANCE WITH RULE 904 UNDER
THE SECURITIES ACT OR (F) PURSUANT TO THE EXEMPTION FROM REGISTRATION PROVIDED
BY RULE 144 UNDER THE SECURITIES ACT (IF AVAILABLE) AND (3) AGREES THAT IT WILL
DELIVER TO EACH PERSON TO WHOM THE SECURITY EVIDENCED HEREBY IS TRANSFERRED A
NOTICE SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND. IN CONNECTION WITH ANY
TRANSFER OF THE SECURITY EVIDENCED HEREBY PRIOR TO THE EXPIRATION OF THE HOLDING
PERIOD APPLICABLE TO SALES OF THE SECURITY EVIDENCED HEREBY UNDER RULE 144(K)
UNDER THE SECURITIES ACT (OR ANY SUCCESSOR PROVISION), THE HOLDER MUST CHECK THE
APPROPRIATE BOX SET FORTH ON THE REVERSE HEREOF RELATING TO THE MANNER OF SUCH
TRANSFER AND SUBMIT THIS CERTIFICATE TO THE TRUSTEE FOR THE CONVERTIBLE
PREFERRED SECURITIES OR THE CONVERTIBLE DEBENTURES, AS THE CASE MAY BE (OR, IF
THIS CERTIFICATE EVIDENCES COMMON STOCK, SUCH HOLDER MUST FURNISH TO THE
TRANSFER AGENT SUCH CERTIFICATIONS, LEGAL OPINIONS OR OTHER INFORMATION AS THE
COMPANY OR McKESSON FINANCING TRUST ("THE TRUST") MAY REASONABLY REQUIRE TO
CONFIRM THAT SUCH TRANSFER IS BEING MADE PURSUANT TO AN EXEMPTION FROM, OR IN A
TRANSACTIONS NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE SECURITIES
ACT). IF THIS CERTIFICATE DOES NOT EVIDENCE COMMON STOCK AND IF THE PROPOSED
TRANSFEREE IS AN INSTITUTIONAL ACCREDITED INVESTOR OR A PURCHASER WHO IS NOT A
U.S. PERSON, THE HOLDER MUST, PRIOR TO SUCH TRANSFER, FURNISH TO THE TRUSTEE FOR
THE CONVERTIBLE PREFERRED SECURITIES OR THE CONVERTIBLE DEBENTURES, AS THE CASE
MAY BE, SUCH CERTIFICATIONS, LEGAL OPINIONS OR OTHER INFORMATION AS THE COMPANY
OR THE TRUST MAY REASONABLY REQUIRE TO CONFIRM THAT SUCH TRANSFER IS BEING MADE
PURSUANT TO AN EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE
REGISTRATION REQUIREMENTS OF THE SECURITIES ACT. THIS LEGEND WILL BE REMOVED
AFTER THE EXPIRATION OF THE HOLDING PERIOD APPLICABLE TO SALES OF THE SECURITY
EVIDENCED HEREBY UNDER RULE 144(K) UNDER THE SECURITIES ACT. AS USED HEREIN, THE
TERMS "OFFSHORE TRANSACTION," "UNITED STATES" AND "U.S. PERSON" HAVE THE
MEANINGS GIVEN TO THEM BY REGULATION S UNDER THE SECURITIES ACT.

     Following the Transfer Restriction Termination Date, any Security or
security issued in exchange or substitution therefor (other than (i) Securities
acquired by McKesson or any Affiliate and (ii) Common Stock issued upon the
conversion or exchange of any Security described in clause (i) above) may upon
surrender of such Security for exchange to any Regular Trustee on behalf of the
Trust in accordance with the provisions of Section 9.2, be exchanged for a new
Security or Securities, of like tenor and aggregate liquidation amount, which
shall not bear the restrictive legend required by this Section 9.1(d).

                                       37
<PAGE>
 
     Any Convertible Preferred Security or Common Stock issued upon the
conversion or exchange of a Convertible Preferred Security that, prior to the
Transfer Restriction Termination Date, is purchased or owned by the Company or
any Affiliate thereof may not be resold by the Company or such Affiliate unless
registered under the Securities Act or resold pursuant to an exemption from the
registration requirements of the Securities Act in a transaction which results
in such Convertible Preferred Securities or Common Stock, as the case may be, no
longer being "restricted securities" (as defined under Rule 144).

     SECTION 9.2.   Transfer of Certificates.

     The Regular Trustees shall provide for the registration of Certificates and
of transfers of Certificates, which will be effected without charge, but only
upon payment in respect of any tax or other government charges that may be
imposed in relation to it. Upon surrender for registration of transfer of any
Certificate, the Regular Trustees shall cause one or more new Certificates to be
issued in the name of the designated transferee or transferees. Every
Certificate surrendered for registration of transfer shall be accompanied by a
written instrument of transfer in form satisfactory to the Regular Trustees duly
executed by the Holder or such Holder's attorney duly authorized in writing.
Each Certificate surrendered for registration of transfer shall be canceled by
the Regular Trustees. A transferee of a Certificate shall be entitled to the
rights and subject to the obligations of a Holder hereunder upon the receipt by
such transferee of a Certificate. By acceptance of a Certificate, each
transferee shall be deemed to have agreed to be bound by this Declaration.

     SECTION 9.3.   Deemed Security Holders.

     The Trustees may treat the Person in whose name any Certificate shall be
registered on the books and records of the Trust as the sole holder of such
Certificate and of the Securities represented by such Certificate for purposes
of receiving Distributions and for all other purposes whatsoever and,
accordingly, shall not be bound to recognize any equitable or other claim to or
interest in such Certificate or in the Securities represented by such
Certificate on the part of any Person, whether or not the Trust shall have
actual or other notice thereof.

     SECTION 9.4.   Book Entry Interests.

     (a)   So long as Convertible Preferred Securities are eligible for book-
entry settlement with the Clearing Agency or unless otherwise required by law,
all Convertible Preferred Securities that are so eligible may be represented by
one or more fully registered Convertible Preferred Security Certificates (each a
"Global Certificate") in global form to be delivered to DTC, the initial
Clearing Agency, by, or on behalf of, the Trust. Such Global Certificates shall
initially be registered on the books and records of the Trust in the name of
Cede & Co., the nominee of DTC, and no Convertible Preferred Security Beneficial
Owner will receive a definitive Convertible Preferred Security Certificate
representing such Convertible Preferred Security Beneficial Owner's interests in
such Global Certificates, except as provided in Section 9.7 below. The transfer
and exchange of beneficial interests in any such Security in global form shall
be effected through the Clearing Agency in accordance with this Declaration and
the procedures of the Clearing Agency therefor.

                                       38
<PAGE>
 
     (b)   Convertible Preferred Securities that upon initial issuance are
beneficially owned by QIBs may, at the option of the Trust, be represented by
one or more Global Certificates (a "144A Global Security"), and Convertible
Preferred Securities that upon initial issuance are beneficially owned by 
Non-U.S. Persons may, at the option of the Trust, be represented by one or more
Global Certificates (a "Regulation S Global Security"). Transfers of interests
in the Convertible Preferred Securities between any 144A Global Security and any
Regulation S Global Security will be made in accordance with the standing
instructions and procedures of the Clearing Agency and its participants. The
Institutional Trustee shall make appropriate endorsements to reflect increases
or decreases in the amount of such Convertible Preferred Securities in global
form to reflect any such transfers.

     Except as provided below, beneficial owners of a Convertible Preferred
Security in global form shall not be entitled to have certificates registered in
their names, will not receive or be entitled to receive physical delivery of
certificates in definitive form and will not be considered Holders of such
Convertible Preferred Security in global form.

     (c)   So long as the Convertible Preferred Securities are eligible for 
book-entry settlement and to the extent Convertible Preferred Securities held by
QIBs or Non-U.S. Persons, as the case may be, are held in a global form, or
unless otherwise required by law, upon any transfer of a definitive Convertible
Preferred Security to a QIB in accordance with Rule 144A or to a Non-U.S. Person
in accordance with Regulation S, unless otherwise requested by the transferor,
and upon receipt of the definitive Convertible Preferred Security or Convertible
Preferred Securities being so transferred, together with a certification from
the transferor that the transfer is being made in compliance with Rule 144A or
Regulation S, as the case may be (or other evidence satisfactory to the
Institutional Trustee on behalf of the Trust), the Institutional Trustee on
behalf of the Trust shall make an endorsement on any 144A Global Security or any
Regula tion S Global Security, as the case may be, to reflect an increase in the
number of Convertible Preferred Securities represented by such Global
Certificate, and the Institutional Trustee on behalf of the Trust shall cancel
such definitive Convertible Preferred Security or Convertible Preferred
Securities in accordance with the standing instructions and procedures of the
Clearing Agency, the number of Convertible Preferred Securities represented by
such Convertible Preferred Security in global form to be increased accordingly;
provided that no definitive Convertible Preferred Security, or portion thereof,
in respect of which the Trust or an Affiliate of the Trust held any beneficial
interest shall be included in such Convertible Preferred Security in global form
until such definitive Convertible Preferred Security is freely tradeable in
accordance with Rule 144(k); provided further that the Trust shall issue
Convertible Preferred Securities in definitive form upon any transfer of a
beneficial interest in the Convertible Preferred Security in global form to the
Company or any Affiliate of the Company.

     (d) Any Global Certificate may be endorsed with or have incorporated in the
text thereof such legends or recitals or changes not inconsistent with the
provisions of this Declaration as may be required by the Clearing Agency, by any
national securities exchange or by the National Association of Securities
Dealers, Inc. in order for the Convertible Preferred Securities to be tradeable
on the PORTAL Market or as may be required for the Convertible Preferred
Securities to be tradeable on any other market developed for trading of
securities pursuant to Rule 144A or required to comply with any applicable law
or any regulation 

                                       39
<PAGE>
 
thereunder or with the rules and regulations of any securities exchange upon
which the Convertible Preferred Securities may be listed or traded or to conform
with any usage with respect thereto, or to indicate any special limitations or
restrictions to which any particular Convertible Preferred Securities are
subject.

     (e)   Unless and until definitive, fully registered Convertible Preferred
Security Certificates (the "Definitive Convertible Preferred Security
Certificates") have been issued to the Convertible Preferred Security Beneficial
Owners of a Convertible Preferred Security in global form pursuant to Section
9.7:

          (i)  the provisions of this Section 9.4 shall be in full force and
     effect with respect to such Convertible Preferred Securities;

         (ii)  the Trust and the Trustees shall be entitled to deal with the
     Clearing Agency for all purposes of this Declaration (including the payment
     of Distributions on the Global Certificates and receiving approvals, votes
     or consents hereunder) as the Holder of such Convertible Preferred
     Securities and the sole holder of the Global Certificates and shall have no
     obligation to the Convertible Preferred Security Beneficial Owners of such
     Convertible Preferred Securities;

        (iii)  to the extent that the provisions of this Section 9.4 conflict
     with any other provisions of this Declaration, the provisions of this
     Section 9.4 shall control; and

         (iv)  the rights of the Convertible Preferred Security Beneficial
     Owners of Convertible Preferred Securities in global form shall be
     exercised only through the Clearing Agency and shall be limited to those
     established by law and agreements between such Convertible Preferred
     Security Beneficial Owners and the Clearing Agency and/or the Clearing
     Agency Participants. The Clearing Agency will make book-entry transfers
     among Clearing Agency Participants and receive and transmit payments of
     Distributions on the Global Certificates to such Clearing Agency
     Participants. DTC will make book entry transfers among the Clearing Agency
     Participants provided, that solely for the purposes of determining whether
     the Holders of the requisite amount of Convertible Preferred Securities
     have voted on any matter provided for in this Declaration, so long as
     Definitive Convertible Preferred Security Certificates have not been
     issued, the Trustees may conclusively rely on, and shall be protected in
     relying on, any written instrument (including a proxy) delivered to the
     Trustees by the Clearing Agency setting forth the Convertible Preferred
     Securities Beneficial Owners' votes or assigning the right to vote on any
     matter to any other Persons either in whole or in part.

     (f) Notwithstanding any other provisions of this Declaration (other than
the provisions set forth in this Section 9.4(f)), a Convertible Preferred
Security in global form may not be transferred as a whole except by the Clearing
Agency to a nominee of the Clearing Agency or by a nominee of the Clearing
Agency to the Clearing Agency or another nominee to a successor Clearing Agency
or a nominee of such successor Clearing Agency.

                                       40
<PAGE>
 
     SECTION 9.5.  Notices to Clearing Agency.

     Whenever a notice or other communication to the Convertible Preferred
Security Holders is required under this Declaration, unless and until Definitive
Convertible Preferred Security Certificates shall have been issued to the
Convertible Preferred Security Beneficial Owners pursuant to Section 9.7, the
Regular Trustees shall give all such notices and communications specified herein
to be given to the Convertible Preferred Security Holders to the Clearing
Agency, and shall have no notice obligations to the Convertible Preferred
Security Beneficial Owners.

     SECTION 9.6.  Appointment of Successor Clearing Agency.

     If any Clearing Agency notifies the Trust that it is unwilling or unable to
continue its services as securities depositary with respect to the Convertible
Preferred Securities, if such Clearing Agency ceases to perform such services,
or if at any time such Clearing Agency ceases to be a clearing agency registered
as such under the Exchange Act when such Clearing Agency is required to be so
registered to act as such depositary, then the Regular Trustees may, in their
sole discretion, appoint a successor Clearing Agency with respect to such
Convertible Preferred Securities.

     SECTION 9.7.  Definitive Convertible Preferred Security Certificates Under
Certain Circumstances.

     If:

     (a) a Clearing Agency notifies the Trust that it is unwilling or unable to
continue its services as securities depositary with respect to the Convertible
Preferred Securities, if at any time such Clearing Agency ceases to be a
clearing agency registered as such under the Exchange Act when such Clearing
Agency is required to be so registered to act as such depositary and no
successor Clearing Agency shall have been appointed pursuant to Section 9.6
within 90 days of such notification;

     (b) the Regular Trustees (with the consent of the Sponsor), in their sole
discretion determine that the Convertible Preferred Securities in global from
shall be exchanged for certificated Convertible Preferred Securities; or

     (c) there shall have occurred and be continuing an Event of Default;

     then:

     (d) Definitive Convertible Preferred Security Certificates shall be
prepared by the Regular Trustees on behalf of the Trust with respect to such
Convertible Preferred Securities; and

     (e) upon surrender of the Global Certificates by the Clearing Agency,
accompanied by registration instructions, the Regular Trustees shall cause
Definitive Convertible Preferred

                                       41
<PAGE>
 
Security Certificates to be delivered to Convertible Preferred Security
Beneficial Owners of such Convertible Preferred Securities in accordance with
the instructions of the Clearing Agency.


Neither the Trustees nor the Trust shall be liable for any delay in delivery of
such instructions and each of them may conclusively rely on and shall be
protected in relying on, said instructions of the Clearing Agency.  The
Definitive Convertible Preferred Security Certificates shall be printed,
lithographed or engraved or may be produced in any other manner as is reasonably
acceptable to the Regular Trustees, as evidenced by their execution thereof, and
may have such letters, numbers or other marks of identification or designation
and such legends or endorsements as the Regular Trustees may deem appropriate,
or as may be required to comply with any law or with any rule or regulation made
pursuant thereto or with any rule or regulation of any stock exchange on which
Convertible Preferred Securities may be listed, or to conform to usage.

     At such time as all interests in a Convertible Preferred Security in global
form have been redeemed, converted, exchanged, repurchased or canceled, such
Convertible Preferred Security in global form shall be, upon receipt thereof,
canceled by the Trust in accordance with standing procedures and instructions of
the Clearing Agency.

     Convertible Preferred Securities that upon initial issuance are
beneficially owned by persons that are neither QIBs nor Non-U.S. Persons will be
issued as Definitive Convertible Preferred Security Certificates and may not be
represented by a Global Certificate.  Convertible Preferred Securities that upon
initial issuance are beneficially owned by persons that are Non-U.S. Persons
may, at the option of the Trust, be issued as Definitive Convertible Preferred
Security Certificates.

     SECTION 9.8.  Mutilated, Destroyed, Lost or Stolen Certificates.

     If:

     (a) any mutilated Certificates should be surrendered to the Regular
Trustees, or if the Regular Trustees shall receive evidence to their
satisfaction of the destruction, loss or theft of any Certificate; and

     (b) there shall be delivered to the Institutional Trustee or the Regular
Trustees such security or indemnity as may be required by them to keep each of
them harmless,

     then:

     in the absence of notice that such Certificate shall have been acquired by
a bona fide purchaser, the Institutional Trustee or any Regular Trustee on
behalf of the Trust shall execute and deliver, in exchange for, or in lieu of,
any such mutilated, destroyed, lost or stolen Certificate, a new Certificate of
like denomination.  In connection with the issuance of any new Certificate under
this Section 9.8, the Institutional Trustee or the Regular Trustees may require
the payment of a sum sufficient to cover any tax or other governmental charge
that may be imposed in connection therewith.  Any duplicate Certificate issued
pursuant to this Section shall 

                                       42
<PAGE>
 
constitute conclusive evidence of an ownership interest in the relevant
Securities, as if originally issued, whether or not the lost, stolen or
destroyed Certificate shall be found at any time.


                                   ARTICLE X

               LIMITATION OF LIABILITY OF HOLDERS OF SECURITIES,
                              TRUSTEES OR OTHERS

     SECTION 10.1.  Liability.

     (a) Except as expressly set forth in this Declaration, the Securities
Guarantees and the terms of the Securities, the Sponsor shall not be:

           (i) personally liable for the return of any portion of the capital
     contributions (or any return thereon) of the Holders of the Securities
     which shall be made solely from assets of the Trust; or

           (ii) be required to pay to the Trust or to any Holder of Securities
     any deficit upon dissolution of the Trust or otherwise.

     (b) The Holder of the Common Securities shall be liable for all of the
debts and obligations of the Trust (other than with respect to the Securities)
to the extent not satisfied out of the Trust's assets.

     (c) Pursuant to (S) 3803(a) of the Business Trust Act, the Holders of the
Convertible Preferred Securities shall be entitled to the same limitation of
personal liability extended to stockholders of private corporations for profit
organized under the General Corporation Law of the State of Delaware.

     SECTION 10.2.  Exculpation.

     (a) No Indemnified Person shall be liable, responsible or accountable in
damages or otherwise to the Trust or any Covered Person for any loss, damage or
claim incurred by reason of any act or omission performed or omitted by such
Indemnified Person in good faith on behalf of the Trust and in a manner such
Indemnified Person reasonably believed to be within the scope of the authority
conferred on such Indemnified Person by this Declaration or by law, except that
an Indemnified Person shall be liable for any such loss, damage or claim
incurred by reason of such Indemnified Person's gross negligence or willful
misconduct with respect to such acts or omissions.

     (b) An Indemnified Person shall be fully protected in relying in good faith
upon the records of the Trust and upon such information, opinions, reports or
statements presented to the Trust by any Person as to matters the Indemnified
Person reasonably believes are within such other Person's professional or expert
competence and who has been selected with reasonable care by or on behalf of the
Trust, including information, opinions, reports or statements as to the

                                       43
<PAGE>
 
value and amount of the assets, liabilities, profits, losses, or any other facts
pertinent to the existence and amount of assets from which Distributions to
Holders of Securities might properly be paid.

     SECTION 10.3.  Fiduciary Duty.

     (a) To the extent that, at law or in equity, an Indemnified Person has
duties (including fiduciary duties) and liabilities relating thereto to the
Trust or to any other Covered Person, an Indemnified Person acting under this
Declaration shall not be liable to the Trust or to any other Covered Person for
its good faith reliance on the provisions of this Declaration.  The provisions
of this Declaration, to the extent that they restrict the duties and liabilities
of an Indemnified Person otherwise existing at law or in equity (other than the
duties imposed on the Institutional Trustee under the Trust Indenture Act), are
agreed by the parties hereto to replace such other duties and liabilities of
such Indemnified Person.

     (b) Unless otherwise expressly provided herein:

           (i) whenever a conflict of interest exists or arises between any
     Covered Persons; or

           (ii) whenever this Declaration or any other agreement contemplated
     herein or therein provides that an Indemnified Person shall act in a manner
     that is, or provides terms that are, fair and reasonable to the Trust or
     any Holder of Securities, the Indemnified Person shall resolve such
     conflict of interest, take such action or provide such terms, considering
     in each case the relative interest of each party (including its own
     interest) to such conflict, agreement, transaction or situation and the
     benefits and burdens relating to such interests, any customary or accepted
     industry practices, and any applicable generally accepted accounting
     practices or principles.  In the absence of bad faith by the Indemnified
     Person, the resolution, action or term so made, taken or provided by the
     Indemnified Person shall not constitute a breach of this Declaration or any
     other agreement contemplated herein or of any duty or obligation of the
     Indemnified Person at law or in equity or otherwise.

     (c) Whenever in this Declaration an Indemnified Person is permitted or
required to make a decision:

           (i) in its "discretion" or under a grant of similar authority, the
     Indemnified Person shall be entitled to consider such interests and factors
     as it desires, including its own interests, and shall have no duty or
     obligation to give any consideration to any interest of or factors
     affecting the Trust or any other Person; or

           (ii) in its "good faith" or under another express standard, the
     Indemnified Person shall act under such express standard and shall not be
     subject to any other or different standard imposed by this Declaration or
     by applicable law.

                                       44
<PAGE>
 
     SECTION 10.4.  Indemnification.

     (a)  (i)     the Debenture Issuer shall indemnify, to the full extent
     permitted by law, any Company Indemnified Person who was or is a party or
     is threatened to be made a party to any threatened, pending or completed
     action, suit or proceeding, whether civil, criminal, administrative or
     investigative (other than an action by or in the right of the Trust) by
     reason of the fact that he is or was a Company Indemnified Person against
     expenses (including attorneys' fees), judgments, fines and amounts paid in
     settlement actually and reasonably incurred by him in connection with such
     action, suit or proceeding if he acted in good faith and in a manner he
     reasonably believed to be in or not opposed to the best interests of the
     Trust, and, with respect to any criminal action or proceeding, had no
     reasonable cause to believe his conduct was unlawful. The termination of
     any action, suit or proceeding by judgment, order, settlement, conviction,
     or upon a plea of nolo contendere or its equivalent, shall not, of itself,
     create a presumption that the Company Indemnified Person did not act in
     good faith and in a manner which he reasonably believed to be in or not
     opposed to the best interests of the Trust, and, with respect to any
     criminal action or proceeding, had no reasonable cause to believe that his
     conduct was unlawful.

           (ii)   The Debenture Issuer shall indemnify, to the full extent
     permitted by law, any Company Indemnified Person who was or is a party or
     is threatened to be made a party to any threatened, pending or completed
     action or suit by or in the right of the Trust to procure a judgment in its
     favor by reason of the fact that he is or was a Company Indemnified Person
     against expenses (including attorneys' fees) actually and reasonably
     incurred by him in connection with the defense or settlement of such action
     or suit if he acted in good faith and in a manner he reasonably believed to
     be in or not opposed to the best interests of the Trust and except that no
     such indemnification shall be made in respect of any claim, issue or matter
     as to which such Company Indemnified Person shall have been adjudged to be
     liable to the Trust unless and only to the extent that the Court of
     Chancery of Delaware or the court in which such action or suit was brought
     shall determine upon application that, despite the adjudication of
     liability but in view of all the circumstances of the case, such person is
     fairly and reasonably entitled to indemnity for such expenses which such
     Court of Chancery or such other court shall deem proper.

           (iii)  To the extent that a Company Indemnified Person shall be
     successful on the merits or otherwise (including dismissal of an action
     without prejudice or the settlement of an action without admission of
     liability) in defense of any action, suit or proceeding referred to in
     paragraphs (i) and (ii) of this Section 10.4(a), or in defense of any
     claim, issue or matter therein, he shall be indemnified, to the full extent
     permitted by law, against expenses (including attorneys' fees) actually and
     reasonably incurred by him in connection therewith.

           (iv)   Any indemnification under paragraphs (i) and (ii) of this
     Section 10.4(a) (unless ordered by a court) shall be made by the Debenture
     Issuer only as authorized in the specific case upon a determination that
     indemnification of the Company Indemnified

                                       45
<PAGE>
 
     Person is proper in the circumstances because he has met the applicable
     standard of conduct set forth in paragraphs (i) or (ii). Such determination
     shall be made (1) by the Regular Trustees by a majority vote of a quorum
     consisting of such Regular Trustees who were not parties to such action,
     suit or proceeding, (2) if such a quorum is not obtainable, or, even if
     obtainable, if a quorum of disinterested Regular Trustees so directs, by
     independent legal counsel in a written opinion, or (3) by the Common
     Security Holder of the Trust.

           (v)    Expenses (including attorneys' fees) incurred by a Company
     Indemnified Person in defending a civil, criminal, administrative or
     investigative action, suit or proceeding referred to in paragraphs (i) and
     (ii) of this Section 10.4(a) shall be paid by the Debenture Issuer in
     advance of the final disposition of such action, suit or proceeding upon
     receipt of an undertaking by or on behalf of such Company Indemnified
     Person to repay such amount if it shall ultimately be determined that he is
     not entitled to be indemnified by the Debenture Issuer as authorized in
     this Section 10.4(a). Notwithstanding the foregoing, no advance shall be
     made by the Debenture Issuer if a determination is reasonably and promptly
     made (i) by the Regular Trustees by a majority vote of a quorum of
     disinterested Regular Trustees, (ii) if such a quorum is not obtainable,
     or, even if obtainable, if a quorum of disinterested Regular Trustees so
     directs, by independent legal counsel in a written opinion or (iii) by the
     Common Security Holder of the Trust, that, based upon the facts known to
     the Regular Trustees, counsel or the Common Security Holder at the time
     such determination is made, such Company Indemnified Person acted in bad
     faith or in a manner that such person did not believe to be in or not
     opposed to the best interests of the Trust, or, with respect to any
     criminal proceeding, that such Company Indemnified Person believed or had
     reasonable cause to believe his conduct was unlawful.  In no event shall
     any advance be made in instances where the Regular Trustees, independent
     legal counsel or Common Security Holder reasonably determine that such
     person deliberately breached his duty to the Trust or its Common or
     Convertible Preferred Security Holders.

           (vi)   The indemnification and advancement of expenses provided by,
     or granted pursuant to, the other paragraphs of this Section 10.4(a) shall
     not be deemed exclusive of any other rights to which those seeking
     indemnification and advancement of expenses may be entitled under any
     agreement, vote of stockholders or disinterested directors of the Debenture
     Issuer or Convertible Preferred Security Holders of the Trust or otherwise,
     both as to action in his official capacity and as to action in another
     capacity while holding such office. All rights to indemnification under
     this Section 10.4(a) shall be deemed to be provided by a contract between
     the Debenture Issuer and each Company Indemnified Person who serves in such
     capacity at any time while this Section 10.4(a) is in effect. Any repeal or
     modification of this Section 10.4(a) shall not affect any rights or
     obligations then existing.

           (vii)  The Debenture Issuer or the Trust may purchase and maintain
     insurance on behalf of any person who is or was a Company Indemnified
     Person against any liability asserted against him and incurred by him in
     any such capacity, or arising out of his status

                                       46
<PAGE>
 
     as such, whether or not the Debenture Issuer would have the power to
     indemnify him against such liability under the provisions of this Section
     10.4(a)

           (viii)  For purposes of this Section 10.4(a), references to "the
     Trust" shall include, in addition to the resulting or surviving entity, any
     constituent entity (including any constituent of a constituent) absorbed in
     a consolidation or merger, so that any person who is or was a director,
     trustee, officer or employee of such constituent entity, or is or was
     serving at the request of such constituent entity as a director, trustee,
     officer, employee or agent of another entity, shall stand in the same
     position under the provisions of this Section 10.4(a) with respect to the
     resulting or surviving entity as he would have with respect to such
     constituent entity if its separate existence had continued.

           (ix)    The indemnification and advancement of expenses provided by,
     or granted pursuant to, this Section 10.4(a) shall, unless otherwise
     provided when authorized or ratified, continue as to a person who has
     ceased to be a Company Indemnified Person and shall inure to the benefit of
     the heirs, executors and administrators of such a person.

     (b)   The Debenture Issuer agrees to indemnify the (i) Institutional
Trustee, (ii) the Delaware Trustee, (iii) any Affiliate of the Institutional
Trustee and the Delaware Trustee, and (iv) any officers, directors,
shareholders, members, partners, employees, representatives, custodians,
nominees or agents of the Institutional Trustee and the Delaware Trustee (each
of the Persons in (i) through (iv) being referred to as a "Fiduciary Indemnified
Person") for, and to hold each Fiduciary Indemnified Person harmless against,
any loss, liability or expense incurred without negligence or bad faith on its
part, arising out of or in connection with the acceptance or administration or
the trust or trusts hereunder, including the costs and expenses (including
reasonable legal fees and expenses) of defending itself against or investigating
any claim or liability in connection with the exercise or performance of any of
its powers or duties hereunder. The provisions of this Section 10.4(b) shall
survive the satisfaction and discharge of this Declaration or the resignation or
removal of the Institutional Trustee or the Delaware Trustee, as the case may
be.

     SECTION 10.5.  Outside Business.

     Any Covered Person, the Sponsor, the Delaware Trustee and the Institutional
Trustee may engage in or possess an interest in other business ventures of any
nature or description, independently or with others, similar or dissimilar to
the business of the Trust, and the Trust and the Holders of Securities shall
have no rights by virtue of this Declaration in and to such independent ventures
or the income or profits derived therefrom, and the pursuit of any such venture,
even if competitive with the business of the Trust, shall not be deemed wrongful
or improper.  No Covered Person, the Sponsor, the Delaware Trustee, or the
Institutional Trustee shall be obligated to present any particular investment or
other opportunity to the Trust even if such opportunity is of a character that,
if presented to the Trust, could be taken by the Trust, and any Covered Person,
shall have the right to take for its own account (individually or as a partner
or fiduciary) or to recommend to others any such particular investment or other
opportunity.  Any Covered Person, the Delaware Trustee and the Institutional
Trustee may engage or be interested in any financial or other transaction with
the Sponsor or any Affiliate of the Sponsor, or may act as depositary for,
trustee or agent for, or act on any committee or body of holders of, securities
or other obligations of the Sponsor or its Affiliates.

                                       47
<PAGE>
 
                                  ARTICLE XI

                                  ACCOUNTING

     SECTION 11.1.  Fiscal Year.

     The fiscal year ("Fiscal Year") of the Trust shall be the same as the
fiscal year of the Company.

     SECTION 11.2.  Certain Accounting Matters.

     (a) At all times during the existence of the Trust, the Regular Trustees
shall keep, or cause to be kept, full books, records and supporting documents,
which shall reflect in detail, each transaction of the Trust.  The books of
account shall be maintained on the accrual method of accounting in compliance
with generally accepted accounting principles, consistently applied.  The Trust
shall use the accrual method of accounting for the United States federal income
tax purposes.  The books of account and the records of the Trust shall be
examined by and reported upon as of the end of each Fiscal Year of the Trust by
a firm of independent certified public accountants selected by the Regular
Trustees.

     (b) The Sponsor shall cause to be prepared and delivered to each of the
Holders of Securities, within 90 days after the end of each Fiscal Year of the
Sponsor, annual financial statements of the Sponsor, including a balance sheet
of the Sponsor as of the end of such Fiscal Year, and the related statements of
income or loss.

     (c) The Regular Trustees shall cause to be duly prepared and delivered to
each of the Holders of Securities, any annual United States federal income tax
information statement, required by the Code, containing such information with
regard to the Securities held by each Holder as is required by the Code and the
Treasury Regulations.  Notwithstanding any right under the Code to deliver any
such statement at a later date, the Regular Trustees shall endeavor to deliver
all such statements within 30 days after the end of each Fiscal Year of the
Trust.

     (d) The Regular Trustees shall cause to be duly prepared and filed with the
appropriate taxing authority, an annual United States federal income tax return,
on a Form 1041 or such other form required by United States federal income tax
law, and any other annual income tax returns required to be filed by the Regular
Trustees on behalf of the Trust with any state or local taxing authority.

     SECTION 11.3.  Banking.

     The Trust shall maintain one or more bank accounts in the name and for the
sole benefit of the Trust; provided, however, that all payments of funds in
respect of the Debentures held by

                                       48
<PAGE>
 
the Institutional Trustee shall be made directly to the Institutional Trustee
Account and no other funds of the Trust shall be deposited in the Institutional
Trustee Account. The sole signatories for such accounts shall be designated by
the Regular Trustees; provided, however, that the Institutional Trustee shall
designate the signatories for the Institutional Trustee Account.

     SECTION 11.4.  Withholding.

     The Trust and the Regular Trustees shall comply with all withholding
requirements under United States federal, state and local law.  The Trust shall
request, and the Holders shall provide to the Trust, such forms or certificates
as are necessary to establish an exemption from withholding with respect to each
Holder, and any representations and forms as shall reasonably be requested by
the Trust to assist it in determining the extent of, and in fulfilling, its
withholding obligations.  The Regular Trustees shall file required forms with
applicable jurisdictions and, unless an exemption from withholding is properly
established by a Holder, shall remit amounts withheld with respect to the Holder
to applicable jurisdictions.  To the extent that the Trust is required to
withhold and pay over any amounts to any authority with respect to distributions
or allocations to any Holder, the amount withheld shall be deemed to be a
distribution in the amount of the withholding to the Holder.  In the event of
any claimed over-withholding, Holders shall be limited to an action against the
applicable jurisdiction.  If the amount required to be withheld was not withheld
from actual Distributions made, the Trust may reduce subsequent Distributions by
the amount of such withholding.  Furthermore, if withholding is imposed on
payments of interest on the Debentures, to the extent such withholding is
attributable to ownership by a specific Holder of Convertible Preferred
Securities, the amount withheld shall be deemed a distribution in the amount of
the withholding to such specific Holder.


                                  ARTICLE XII

                            AMENDMENTS AND MEETINGS

     SECTION 12.1.  Amendments.

     Except as otherwise provided in this Declaration or by any applicable terms
of the Securities,

     (a) this Declaration may only be amended by a written instrument approved
and executed by the Regular Trustees (or, if there are more than two Regular
Trustees a majority of the Regular Trustees) and:

           (i)     if the amendment affects the rights, powers, duties,
     obligations or immunities of the Institutional Trustee, also by the
     Institutional Trustee; and

           (ii)    if the amendment affects the rights, powers, duties,
     obligations or immunities of the Delaware Trustee, also by the Delaware
     Trustee;

                                       49
<PAGE>
 
     (b)   no amendment shall be made, and any such purported amendment shall be
void and ineffective:

           (i)     unless, in the case of any proposed amendment, the
     Institutional Trustee shall have first received an Officers' Certificate
     from each of the Trust and the Sponsor that such amendment is permitted by,
     and conforms to, the terms of this Declaration (including the terms of the
     Securities); 

           (ii)    unless, in the case of any proposed amendment which affects
     the rights, powers, duties, obligations or immunities of the Institutional
     Trustee, the Institutional Trustee shall have first received:

               (A) an Officers' Certificate from each of the Trust and the
          Sponsor that such amendment is permitted by, and conforms to, the
          terms of this Declaration (including the terms of the Securities); and

               (B) an opinion of counsel (who may be counsel to the Sponsor or
          the Trust) that such amendment is permitted by, and conforms to, the
          terms of this Declaration (including the terms of the Securities); and

           (iii)   to the extent the result of such amendment would be to:

               (A) cause the Trust to fail to continue to be classified for
          purposes of United States federal income taxation as a grantor trust;

               (B) reduce or otherwise adversely affect the powers of the
          Institutional Trustee; or

               (C) cause the Trust to be deemed to be an Investment Company
          required to be registered under the Investment Company Act;

     (c) at such time after the Trust has issued any securities that remain
outstanding, any amendment that would adversely affect the rights, privileges or
preferences of any Holder of Securities may be effected only with such
additional requirements as may be set forth in the terms of such Securities;

     (d) Section 9.1(c) and this Section 12.1 shall not be amended without the
consent of all of the Holders of the Securities;

     (e) Article IV shall not be amended without the consent of the Holders of a
Majority in liquidation amount of the Common Securities;

     (f) the rights of the holders of the Common Securities under Article V to
increase or decrease the number of, and appoint and remove Trustees shall not be
amended without the consent of the Holders of a Majority in liquidation amount
of the Common Securities; and

                                       50
<PAGE>
 
     (g) notwithstanding Section 12.1(c), this Declaration may be amended from
time to time by the Holders of a Majority in liquidation amount of the Common
Securities and the Institutional Trustee, without the consent of the Holders of
the Convertible Preferred Securities to:

           (i)     cure any ambiguity, correct or supplement any provision in
     this Declaration that may be inconsistent with any other provision, or to
     make any other provisions with respect to matters or questions arising
     under this Declaration, which shall not be inconsistent with the other
     provisions of this Declaration; or

           (ii)    to modify, eliminate or add to any provisions of this
     Declaration to such extent as shall be necessary to ensure that the Trust
     will be classified for United States federal income tax purposes as a
     grantor trust at all times that any Securities are outstanding or to ensure
     that the Trust will not be required to register as an investment company
     under the Investment Company Act;

provided, however, such action shall not adversely affect in any material
respect the interests of any Holder of Securities;

     (h) this Declaration may be amended by the Holders of a Majority in
liquidation amount of the Common Securities and the Institutional Trustee if:

           (i)     the Holders of a Majority in liquidation amount of the
     Convertible Preferred Securities consent to such amendment and

           (ii)    the Regular Trustees have received an opinion of nationally
     recognized independent counsel experienced in such matters to the effect
     that such amendment or the exercise of any power granted to the Regular
     Trustees in accordance with such amendment will not affect the Trust's
     status as a grantor trust for United States federal income tax purposes or
     the Trust's exemption from status as an "investment company" under the
     Investment Company Act,

provided, that without the consent of each Holder of Securities, this
Declaration may not be amended to:

          (x)      change the amount or timing of any distribution on the
     Securities or otherwise adversely affect the amount of any distribution
     required to be made in respect of the Securities as of a specified date or

          (y)      restrict the right of a Holder of Securities to institute
     suit for the enforcement of any such payment on or after such date.

     (i)  Any amendments of this Declaration shall become effective when notice
thereof is given to Holders of Securities.

                                       51
<PAGE>
 
     SECTION 12.2.  Meetings of the Holders of Securities; Action by Written
Consent.

     (a) Meetings of the Holders of any class of Securities may be called at any
time by the Regular Trustees (or as provided in the terms of the Securities) to
consider and act on any matter on which Holders of such class of Securities are
entitled to act under the terms of this Declaration, the terms of the Securities
or the rules of any stock exchange on which the Convertible Preferred Securities
are listed or admitted for trading. The Regular Trustees shall call a meeting of
the Holders of such class if directed to do so by the Holders of at least 25% in
liquidation amount of such class of Securities. Such direction shall be given by
delivering to the Regular Trustees one or more calls in a writing stating that
the signing Holders of Securities wish to call a meeting and indicating the
general or specific purpose for which the meeting is to be called. Any Holders
of Securities calling a meeting shall specify in writing the Security
Certificates held by the Holders of Securities exercising the right to call a
meeting and only those Securities specified shall be counted for purposes of
determining whether the required percentage set forth in the second sentence of
this paragraph has been met.

     (b) Except to the extent otherwise provided in the terms of the Securities,
the following provisions shall apply to meetings of Holders of Securities:

           (i)     notice of any such meeting shall be given to all the Holders
     of Securities having a right to vote thereat at least 7 days and not more
     than 60 days before the date of such meeting. Whenever a vote, consent or
     approval of the Holders of Securities is permitted or required under this
     Declaration or the rules of any stock exchange on which the Convertible
     Preferred Securities are listed or admitted for trading, such vote, consent
     or approval may be given at a meeting of the Holders of Securities. Any
     action that may be taken at a meeting of the Holders of Securities may be
     taken without a meeting if a consent in writing setting forth the action so
     taken is signed by the Holders of Securities owning not less than the
     minimum amount of Securities in liquidation amount that would be necessary
     to authorize or take such action at a meeting at which all Holders of
     Securities having a right to vote thereon were present and voting. Prompt
     notice of the taking of action without a meeting shall be given to the
     Holders of Securities entitled to vote who have not consented in writing.
     The Regular Trustees may specify that any written ballot submitted to the
     Security Holder for the purpose of taking any action without a meeting
     shall be returned to the Trust within the time specified by the Regular
     Trustees;

           (ii)    each Holder of a Security may authorize any Person to act for
     it by proxy on all matters in which a Holder of Securities is entitled to
     participate, including waiving notice of any meeting, or voting or
     participating at a meeting. No proxy shall be valid after the expiration of
     11 months from the date thereof unless otherwise provided in the proxy.
     Every proxy shall be revocable at the pleasure of the Holder of Securities
     executing it. Except as otherwise provided herein, all matters relating to
     the giving, voting or validity of proxies shall be governed by the General
     Corporation Law of the State of Delaware relating to proxies, and judicial
     interpretations thereunder, as if the Trust were a Delaware corporation and
     the Holders of the Securities were stockholders of a Delaware corporation;

                                       52
<PAGE>
 
           (iii)   each meeting of the Holders of the Securities shall be
     conducted by the Regular Trustees or by such other Person that the Regular
     Trustees may designate; and

           (iv)    unless the Business Trust Act, this Declaration, the terms of
     the Securities, the Trust Indenture Act or the listing rules of any stock
     exchange on which the Convertible Preferred Securities are then listed or
     trading, otherwise provides, the Regular Trustees, in their sole
     discretion, shall establish all other provisions relating to meetings of
     Holders of Securities, including notice of the time, place or purpose of
     any meeting at which any matter is to be voted on by any Holders of
     Securities, waiver of any such notice, action by consent without a meeting,
     the establishment of a record date, quorum requirements, voting in person
     or by proxy or any other matter with respect to the exercise of any such
     right to vote.


                                 ARTICLE XIII

                 REPRESENTATIONS OF INSTITUTIONAL TRUSTEE AND
                               DELAWARE TRUSTEE

     SECTION 13.1.  Representations and Warranties of Institutional Trustee.

     The Trustee that acts as initial Institutional Trustee represents and
warrants to the Trust and to the Sponsor at the date of this Declaration, and
each Successor Institutional Trustee represents and warrants, as applicable, to
the Trust and the Sponsor at the time of the Successor Institutional Trustee's
acceptance of its appointment as Institutional Trustee that:

     (a) the Institutional Trustee is a national banking association with trust
powers, duly organized, validly existing and in good standing, with trust power
and authority to execute and deliver, and to carry out and perform its
obligations under the terms of, the Declaration;

     (b) the execution, delivery and performance by the Institutional Trustee of
the Declaration has been duly authorized by all necessary corporate action on
the part of the Institutional Trustee.  The Declaration has been duly executed
and delivered by the Institutional Trustee, and it constitutes a legal, valid
and binding obligation of the Institutional Trustee, enforceable against it in
accordance with its terms, subject to applicable bankruptcy, reorganization,
moratorium, insolvency, and other similar laws affecting creditors' rights
generally and to general principles of equity and the discretion of the court
(regardless of whether the enforcement of such remedies is considered in a
proceeding in equity or at law);

     (c) the execution, delivery and performance of the Declaration by the
Institutional Trustee does not conflict with or constitute a breach of the
charter or by-laws of the Institutional Trustee; and

     (d) no consent, approval or authorization of, or registration with or
notice to, any state or federal banking authority is required for the execution,
delivery or performance by the Institutional Trustee, of the Declaration.

                                       53
<PAGE>
 
     SECTION 13.2.  Representations and Warranties of Delaware Trustee.

     The Trustee that acts as initial Delaware Trustee represents and warrants
to the Trust and to the Sponsor at the date of this Declaration, and each
Successor Delaware Trustee represents and warrants to the Trust and the Sponsor
at the time of the Successor Delaware Trustee's acceptance of its appointment as
Delaware Trustee that:

     (a) The Delaware Trustee is a Delaware corporation, duly organized, validly
existing and in good standing, with corporate power and authority to execute and
deliver, and to carry out and perform its obligations under the terms of, the
Declaration.

     (b) The Delaware Trustee has been authorized to perform its obligations
under the Certificate of Trust and the Declaration.  The Declaration under
Delaware law constitutes a legal, valid and binding obligation of the Delaware
Trustee, enforceable against it in accordance with its terms, subject to
applicable bankruptcy, reorganization, moratorium, insolvency, and other similar
laws affecting creditors' rights generally and to general principles of equity
and the discretion of the court (regardless of whether the enforcement of such
remedies is considered in a proceeding in equity or at law).

     (c) No consent, approval or authorization of, or registration with or
notice to, any Delaware or federal banking authority is required for the
execution, delivery or performance by the Delaware Trustee, of the Declaration.

     (d) The Delaware Trustee is a natural person who is a resident of the State
of Delaware or, if not a natural person, an entity which has its principal place
of business in the State of Delaware.


                                  ARTICLE XIV

                                 MISCELLANEOUS

     SECTION 14.1.  Notices.

     All notices provided for in this Declaration shall be in writing, duly
signed by the party giving such notice, and shall be delivered, telecopied or
mailed by first class mail, as follows:

                                       54
<PAGE>
 
     (a) if given to the Trust, in care of the Regular Trustees at the Trust's
mailing address set forth below (or such other address as the Trust may give
notice of to the Holders of the Securities):

         McKesson Financing Trust            
         c/o McKesson Corporation            
         McKesson Plaza                      
         One Post Street                     
         San Francisco, California  94104    
         Attention:  General Counsel         


     (b) if given to the Delaware Trustee, at the mailing address set forth
below (or such other address as Delaware Trustee may give notice of to the
Holders of the Securities):

         First Chicago Delaware Inc.      
         300 King street                  
         Wilmington, Delaware  19801      
         Attention: Michael J. Majchrzak  

     (c) if given to the Institutional Trustee, at its Corporate Trust Office's
mailing address set forth below (or such other address as the Institutional
Trustee may give notice of to the Holders of the Securities).

         The First National Bank of Chicago             
         One First National Plaza, Suite 0126           
         Chicago, Illinois  60670-0126                  
         Attention:  Corporate Trust Services Division  

     (d) if given to the Holder of the Common Securities, at the mailing address
of the Sponsor set forth below (or such other address as the Holder of the
Common Securities may give notice to the Trust):

         McKesson Corporation               
         McKesson Plaza                     
         One Post Street                    
         San Francisco, California  94104   
         Attention:  General Counsel        

     (e) if given to any other Holder, at the address set forth on the books and
records of the Trust.

     All such notices shall be deemed to have been given when received in
person, telecopied with receipt confirmed, or mailed by first class mail,
postage prepaid except that if a notice or other document is refused delivery or
cannot be delivered because of a changed address of which no notice was given,
such notice or other document shall be deemed to have been delivered on the date
of such refusal or inability to deliver.

                                       55
<PAGE>
 
     SECTION 14.2.  Governing Law.

     This Declaration and the rights of the parties hereunder shall be governed
by and interpreted in accordance with the laws of the State of Delaware and all
rights and remedies shall be governed by such laws without regard to principles
of conflict of laws.

     SECTION 14.3.  Intention of the Parties.

     It is the intention of the parties hereto that the Trust be classified for
United States federal income tax purposes as a grantor trust.  The provisions of
this Declaration shall be interpreted to further this intention of the parties.

     SECTION 14.4.  Headings.

     Headings contained in this Declaration are inserted for convenience of
reference only and do not affect the interpretation of this Declaration or any
provision hereof.

     SECTION 14.5.  Successors and Assign.

     Whenever in this Declaration any of the parties hereto is named or referred
to, the successors and assigns of such party shall be deemed to be included, and
all covenants and agreements in this Declaration by the Sponsor and the Trustees
shall bind and inure to the benefit of their respective successors and assigns,
whether so expressed.

     SECTION 14.6.  Partial Enforceability.

     If any provision of this Declaration, or the application of such provision
to any Person or circumstance, shall be held invalid, the remainder of this
Declaration, or the application of such provision to persons or circumstances
other than those to which it is held invalid, shall not be affected thereby.

     SECTION 14.7.  Counterparts.

     This Declaration may contain more than one counterpart of the signature
page and this Declaration may be executed by the affixing of the signature of
each of the Trustees to one of such counterpart signature pages.  All of such
counterpart signature pages shall be read as though one, and they shall have the
same force and effect as though all of the signers had signed a single signature
page.

                                       56
<PAGE>
 
     IN WITNESS WHEREOF, the undersigned has caused these presents to be
executed as of the day and year first above written.



                            ____________________________________________________
                            IVAN D. MEYERSON, as Regular Trustee
                            Solely as trustee and not in his individual capacity


                            ____________________________________________________
                            WILLIAM A. ARMSTRONG, as Regular Trustee
                            Solely as trustee and not in his individual capacity


                            FIRST CHICAGO DELAWARE INC., as
                            Delaware Trustee


                            By:  /s/ Richard D. Manella
                                 -----------------------------------------------
                                 Name: Richard D. Manella
                                 Title:  Vice President


                            THE FIRST NATIONAL BANK OF CHICAGO,
                            as Institutional Trustee


                            By:  /s/ Richard D. Manella
                                 -----------------------------------------------
                                 Name: Richard D. Manella
                                 Title:  Vice President


                            McKESSON CORPORATION, as Sponsor


                            By:  /s/ Ivan D. Meyerson
                                 -----------------------------------------------
                                 Name: Ivan D. Meyerson
                                 Title:  Vice President

                                       57
<PAGE>
 
                                    ANNEX I

                                   TERMS OF
                      5% CONVERTIBLE PREFERRED SECURITIES
                       5% CONVERTIBLE COMMON SECURITIES

     Pursuant to Section 7.1 of the Amended and Restated Declaration of Trust,
dated as of February 20, 1997 (as amended from time to time, the "Declaration"),
the designation, rights, privileges, restrictions, preferences and other terms
and provisions of the Convertible Preferred Securities and the Common Securities
are set out below (each capitalized term used but not defined herein has the
meaning set forth in the Declaration or, if not defined in such Declaration, as
defined in the Offering Memorandum referred to below):

     1.   Designation and Number.
          ---------------------- 

     (a)  Convertible Preferred Securities.  3,500,000 Convertible Preferred
          --------------------------------                                  
Securities of the Trust (4,000,000 Convertible Preferred Securities if the
Initial Purchaser's over-allotment option is exercised in full) with an
aggregate liquidation amount with respect to the assets of the Trust of One
Hundred Seventy-Five Million Dollars ($175,000,000) (Two Hundred Million Dollars
($200,000,000) if the Initial Purchaser's over-allotment option is exercised in
full), and a liquidation amount with respect to the assets of $50 per
convertible preferred security, are hereby designated for the purposes of
identification only as "5% Trust Convertible Preferred Securities" (the
"Convertible Preferred Securities").  The Convertible Preferred Security
Certificates evidencing the Convertible Preferred Securities shall be
substantially in the form of Exhibit A-1 to the Declaration, with such letters,
numbers, notations, other means of identification or designation or other
changes or additions thereto or deletions therefrom as may be required by
ordinary usage, custom or practice and such legends or endorsements required by
law, state exchange rule and agreements to which the Trust is subject, if any
(provided that any such notation, legend or endorsement is in a form acceptable
to the Trust).

     (b)  Common Securities. 108,260 Common Securities of the Trust (123,720
          -----------------                                                 
Common Securities if the Initial Purchaser's over-allotment option is exercised
in full) with an aggregate liquidation amount with respect to the assets of the
Trust of Five Million Four Hundred Thirteen Thousand Dollars ($5,413,000) (Six
Million One Hundred Eighty-Six Thousand Dollars ($6,186,000) if the Initial
Purchaser's over-allotment option is exercised in full), and a liquidation
amount with respect to the assets of the Trust of $50 per common security, are
hereby designated for the purposes of identification only as "5% Common
Securities" (the "Common Securities").  The Common Securities Certificates
evidencing the Common Securities shall be in the form of Exhibit A-2 to the
Declaration, with such letters, numbers, notations, other means of
identification or designation or other changes or additions thereto or deletions
therefrom as may be required by ordinary usage, custom or practice and such
legends or endorsements required by law, state exchange rule and agreements to
which the Trust is subject, if any (provided that any such notation, legend or
endorsement is in a form acceptable to the Trust).

                                      I-1
<PAGE>
 
     2.   Distributions.
          ------------- 

     (a)  Distributions payable on each Security will be fixed at a rate per
annum of 5% (the "Coupon Rate") of the stated liquidation amount of $50 per
Security, such rate being the rate of interest payable on the Debentures to be
held by the Institutional Trustee.  Distributions in arrears for more than one
quarter will bear interest thereon compounded quarterly at the Coupon Rate (to
the extent permitted by applicable law).  The term "Distributions" as used
herein includes such interest payable unless otherwise stated.  A Distribution
is payable only to the extent that payments are made in respect of the
Debentures held by the Institutional Trustee and to the extent the Institutional
Trustee has funds available therefor.  The amount of Distributions payable for
any period will be computed for any full quarterly Distribution period on the
basis of a 360-day year of twelve 30-day months, and for any period shorter than
a full quarterly Distribution period for which Distributions are computed,
Distributions will be computed on the basis of the actual number of days elapsed
per 30-day month.

     (b)  Distributions on the Securities will be cumulative, will accrue from
February 20, 1997 and will be payable quarterly in arrears, on March 1, June 1,
September 1 and December 1 of each year, commencing on June 1, 1997, except as
otherwise described below.  So long as the Debenture Issuer shall not be in
default in the payment of interest on the Debentures, the Debenture Issuer has
the right under the Indenture to defer payments of interest on the Debentures
by extending the interest payment period from time to time on the Debentures for
a period not exceeding 20 consecutive quarters (each an "Extension Period"),
during which Extension Period no interest shall be due and payable on the
Debentures, provided that no Extension Period shall last beyond the date of
maturity or any redemption date of the Debentures.  As a consequence of such
deferral, Distributions will also be deferred.  Despite such deferral, quarterly
Distributions will continue to accrue with interest thereon (to the extent
permitted by applicable law) at the Coupon Rate compounded quarterly during any
such Extension Period.  Prior to the termination of any such Extension Period,
the Debenture Issuer may further extend such Extension Period; provided that
such Extension Period together with all such previous and further extensions
thereof may not exceed 20 consecutive quarters or extend beyond the maturity or
any redemption date of the Debentures.  Payments of accrued Distributions and,
to the extent permitted by applicable law, accrued interest thereon shall be
payable on the Distribution payment date on which the relevant Extension Period
terminates and shall be payable to Holders as they appear on the books and
records of the Trust at the close of business on the record date next preceding
such Distribution payment date.  Upon the termination of any Extension Period
and the payment of all amounts then due, the Debenture Issuer may commence a new
Extension Period, subject to the above requirements.  Each Extension Period, if
any, will end on an interest payment date for the Debentures; such date will
also be a Distribution payment date for the Securities.  In the event that the
Debenture Issuer exercises its right to defer payment of interest, then during
such Extension Period the Debenture Issuer shall not (a) declare or pay
dividends on, make distributions with respect to, or redeem, purchase or
acquire, or make a liquidation payment with respect to, any of its capital
stock, or (b) make any payment of interest, principal or premium, if any, on or
repay, repurchase or redeem any debt securities issued by the Debenture Issuer
that rank pari passu with 

                                      I-2
<PAGE>
 
or junior in interest to the Debentures or make any guarantee payments with
respect to any guarantee by the Debenture Issuer of the debt securities of any
subsidiary of the Debenture Issuer if such guarantee ranks pari passu with or
junior in interest to the Debentures (other than (i) as a result of a
reclassification of the capital stock of the Debenture Issuer or the exchange or
conversion of one class or series of the capital stock of the Debenture Issuer
for another class or series of the capital stock of the Debenture Issuer, (ii)
the purchase of fractional interests in shares of the capital stock of the
Debenture Issuer pursuant to the conversion or exchange provisions of such
capital stock or the security being converted into or exchanged for such capital
stock, (iii) dividends or distributions in Common Stock of the Debenture Issuer,
(iv) any declaration of a dividend in connection with the implementation of a
stockholders' rights plan, or the issuance of stock under any such plan in the
future, or the redemption or repurchase of any such rights pursuant thereto, (v)
payments under the Securities Guarantees, (vi) purchases of Common Stock of the
Debenture Issuer related to the issuance of Common Stock of the Debenture Issuer
or rights under any of the Debenture Issuer's benefit plans for its directors,
officers or employees and (vii) obligations under any dividend reinvestment and
stock purchase plans).

     (c)  Distributions on the Securities will be payable to the Holders thereof
as they appear on the books and records of the Trust on the relevant record
dates, which shall be fifteen days prior to the relevant payment dates, which
payment dates correspond to the record and interest payment dates on the
Debentures.  The relevant record dates for the Common Securities shall be the
same record dates as for the Convertible Preferred Securities.  Distributions
payable on any Securities that are not punctually paid on any Distribution
payment date, as a result of the Debenture Issuer having failed to make a
payment under the Debentures, will cease to be payable to the Person in whose
name such Securities are registered on the relevant record date, and such
defaulted Distribution will instead be payable to the Person in whose name such
Securities are registered on the special record date or other specified date
determined in accordance with the Indenture.  If any date on which Distributions
are payable on the Securities is not a Business Day, then payment of the
Distributions payable on such date will be made on the next succeeding day that
is a Business Day (and without any interest or other payment in respect of any
such delay) except that, if such Business Day is in the next succeeding calendar
year, such payment shall be made on the immediately preceding Business Day, in
each case with the same force and effect as if made on such date.

     (d)  In the event of an election by the Holder to convert its Securities
through the Conversion Agent into Common Stock pursuant to the terms of the
Securities as set forth in this Annex I to the Declaration, no payment,
allowance or adjustment shall be made with respect to accumulated and unpaid
Distributions on such Securities, or be required to be made; provided, however,
that Holders of Securities at the close of business on any record date for the
payment of Distributions will be entitled to receive the Distributions payable
on such Securities on the corresponding payment date notwithstanding the
conversion of such Securities into Common Stock following such record date;
provided, further that if the date of any redemption of related Debentures falls
between such record date and such corresponding payment date, the amount of such
Distribution shall include accumulated and unpaid Distributions accrued to but
excluding such date of redemption and such payment shall be made to the
converting holder.

     (e)  In the event that there is any money or other property held by or for
the Trust that is not accounted for hereunder, such property shall be
distributed Pro Rata (as defined herein) among the Holders of the Securities.

                                      I-3
<PAGE>
 
     3.   Liquidation Distribution Upon Dissolution.
          ----------------------------------------- 

     The Debenture Issuer will have the right at any time to cause the Trust to
be dissolved with the result that, after satisfaction of creditors of the Trust,
Debentures having an aggregate principal amount equal to the aggregate stated
liquidation amount of the Convertible Preferred Securities and the Common
Securities will be distributed on a pro rata basis to the Holders of the
Convertible Preferred Securities and the Common Securities in liquidation of
such Holders' interests in the Trust, within 90 days following notice given to
the Holders of the Convertible Preferred Securities, subject to the Regular
Trustees' receipt of an opinion of nationally recognized independent counsel
experienced in such matters to the effect that the Holders will not recognize
any income, gain or loss for United States federal income tax purposes as a
result of the dissolution of the Trust and such distribution to Holders of
Convertible Preferred Securities.

     In the event of any voluntary or involuntary liquidation, dissolution,
winding-up or termination of the Trust (each a "Liquidation"), the Holders of
the Securities on the date of the Liquidation will be entitled to receive out of
the assets of the Trust available for distribution to Holders of Securities
after satisfaction of liabilities of creditors an amount equal to the aggregate
of the stated liquidation amount of $50 per Security plus accrued and unpaid
Distributions thereon to the date of payment (such amount being the "Liquidation
Distribution"), unless, in connection with such Liquidation, Debentures in an
aggregate stated principal amount equal to the aggregate stated liquidation
amount of such Securities, with an interest rate equal to the Coupon Rate of,
and bearing accrued and unpaid interest in an amount equal to the accrued and
unpaid Distributions on, such Securities, shall have been distributed on a Pro
Rata basis to the Holders of the Securities in exchange for such Securities.

     If, upon any such Liquidation, the Liquidation Distribution can be paid
only in part because the Trust has insufficient assets available to pay in full
the aggregate Liquidation Distribution, then the amounts payable directly by the
Trust on the Securities shall be paid on a Pro Rata basis.

     4.   Redemption and Distribution.
          --------------------------- 

     (a)  The Debentures will mature on June 1, 2027, and may be redeemed, in
whole or in part, at any time on or after March 4, 2000, or at any time in
certain circumstances upon the occurrence of a Tax Event (as defined below).
Upon the repayment of the Debentures in whole or in part, whether at maturity,
upon redemption (either at the option of the Debenture Issuer or pursuant to a
Tax Event as described below) or otherwise, the proceeds from such repayment or
payment shall be simultaneously applied to redeem Securities having an aggregate
liquidation amount equal to the aggregate principal amount of the Debentures so
repaid or redeemed at a redemption price per Security equal to the redemption
price of the Debentures, together with accrued and unpaid Distributions thereon
to, but excluding, the date of the redemption, payable in cash (the "Redemption
Price").  Holders will be given not less than 30 nor more than 60 days' notice
of such redemption.

                                      I-4
<PAGE>
 
     (b)  If fewer than all the outstanding Securities are to be so redeemed,
the Common Securities and the Convertible Preferred Securities will be redeemed
Pro Rata and the Convertible Preferred Securities to be redeemed will be as
described in Section 4(f) below.

     (c)  If, at any time, a Tax Event or an Investment Company Event (each, as
defined below, a "Special Event") shall occur and be continuing, the Regular
Trustees may with the consent of the Debenture Issuer, except in certain limited
circumstances in relation to a Tax Event described in this Section 4(c),
dissolve the Trust and, after satisfaction of creditors, cause Debentures held
by the Institutional Trustee, having an aggregate principal amount equal to the
aggregate stated liquidation amount of, with an interest rate identical to the
Coupon Rate of, and accrued and unpaid interest equal to accrued and unpaid
Distributions on, and having the same record date for payment as the Securities,
to be distributed to the Holders of the Securities in liquidation of such
Holders' interests in the Trust on a Pro Rata basis, within 90 days following
the occurrence of such Special Event (the "90 Day Period"); provided, however,
that such dissolution and distribution shall be conditioned on (i) the Regular
Trustees' receipt of an opinion of nationally recognized independent tax counsel
experienced in such matters (a "No Recognition Opinion"), which opinion may rely
on published revenue rulings of the Internal Revenue Service, to the effect that
the Holders of the Securities will not recognize any gain or loss for United
States federal income tax purposes as a result of the dissolution of the Trust
and the distribution of Debentures, (ii) in the case of a Tax Event, the
Debenture Issuer or the Trust being unable to avoid, within the 90 Day Period,
the Tax Event by taking some ministerial action, such as filing a form or making
an election, or pursuing some other similar reasonable measure that has no
adverse effect on the Trust, the Debenture Issuer, the Sponsor or the Holders of
the Securities ("Ministerial Action"), and (iii) the Debenture Issuer's prior
written consent to such dissolution and distribution.

     Furthermore, if (i) after receipt of a Dissolution Tax Opinion (as defined
hereinafter) by the Regular Trustees, the Debenture Issuer has received an
opinion (a "Redemption Tax Opinion") of nationally recognized independent tax
counsel experienced in such matters that, as a result of a Tax Event, there is
more than an insubstantial risk that the Debenture Issuer would be precluded
from deducting the interest on the Debentures for United States federal income
tax purposes even after the Debentures were distributed to the Holders of
Securities in liquidation of such Holders' interests in the Trust as described
in this Section 4(c), or (ii) the Regular Trustees shall have been informed by
such tax counsel that it cannot deliver a No Recognition Opinion to the Trust,
the Debenture Issuer shall have the right, upon not less than 30 nor more than
60 days' notice, to redeem the Debentures, in whole or in part, at a redemption
price equal to 100% of the principal amount thereof plus accrued and unpaid
interest thereon, for cash within 90 days following the occurrence of such Tax
Event.  Following such redemption, Securities with an aggregate liquidation
amount equal to the aggregate principal amount of the Debentures so redeemed
shall be redeemed by the Trust at the Redemption Price on a Pro Rata basis;
provided, however, that, if at the time there is available to the Debenture
Issuer or the Trust the opportunity to eliminate, within such 90 day period, the
Tax Event by taking some Ministerial Action, the Trust or the Debenture Issuer
will pursue such Ministerial Action in lieu of redemption.

                                      I-5
<PAGE>
 
     "Tax Event" means that the Regular Trustees shall have received an opinion
of nationally recognized independent tax counsel experienced in such matters (a
"Dissolution Tax Opinion") to the effect that on or after February 20, 1997, as
a result of (a) any amendment to, clarification of, or change (including any
announced prospective change) in the laws (or any regulations thereunder) of the
United States or any political subdivision or taxing authority thereof or
therein affecting taxation, (b) any judicial decision, official administrative
pronouncement, ruling, regulatory procedure, notice or announcement, including
any notice or announcement of intent to adopt such procedures or regulations (an
"Administrative Action") or (c) any amendment to, clarification of, or change in
the official position or the interpretation of such Administrative Action or
judicial decision that differs from the theretofore generally accepted position,
in each case, by any legislative body, court, governmental authority or
regulatory body, irrespective of the manner in which such amendment,
clarification, change or Administrative Action is made known, which amendment,
clarification, change or Administrative Action is effective or such
pronouncement or decision is announced, in each case, on or after, February 20,
1997, there is the creation by such amendment, clarification, change or
Administrative Action of more than an insubstantial risk that (i) the Trust is,
or will be within 90 days of the date thereof, subject to United States federal
income tax with respect to income accrued or received on the Debentures, (ii)
the Trust is, or will be within 90 days of the date thereof, subject to more
than a de minimis amount of taxes (other than withholding taxes), duties or
other governmental charges, or (iii) interest paid in cash by the Debenture
Issuer to the Trust on the Debentures is not, or within 90 days of the date
thereof will not be, deductible, in whole or in part, by the Debenture Issuer
for United States federal income tax purposes. Notwithstanding the foregoing, a
Tax Event shall not include any change in tax law that requires the Debenture
Issuer for United States federal income tax purposes to defer taking a deduction
for any original issue discount ("OID") that accrues with respect to the
Debentures until the interest payment related to such OID is paid by the
Debenture Issuer in cash; provided, that such change in tax law does not create
more than an insubstantial risk that the Debenture Issuer will be prevented from
taking a deduction for OID accruing with respect to the Debentures at a date
that is no later than the date the interest payment related to such OID is
actually paid by the Debenture Issuer in cash.

     "Investment Company Event" means that the Regular Trustees shall have
received an opinion of nationally recognized independent counsel experienced in
such matters to the effect that, as a result of the occurrence of a change in
law or regulation or a written change in interpretation or application of law or
regulation by any legislative body, court, governmental agency or regulatory
authority on or after February 20, 1997 (a "Change in 1940 Act Law"), there is
more than an insubstantial risk that the Trust is or will be considered an
"investment company" that is required to be registered under the Investment
Company Act of 1940, as amended (the "1940 Act").

     After the date fixed by the Regular Trustees for any distribution of
Debentures upon dissolution of the Trust: (i) the Securities will no longer be
deemed to be outstanding, (ii) The Depository Trust Company (the "Depository")
or its nominee (or any successor Clearing Agency or its nominee), as the record
Holder of the Convertible Preferred Securities held in global form, will receive
a registered certificate or certificates representing the Debentures held in
global form to be delivered upon such distribution, and (iii) certificates
representing Securities held in 

                                      I-6
<PAGE>
 
definitive form, except for certificates representing Convertible Preferred
Securities held by the Depository or its nominee (or any successor Clearing
Agency or its nominee), will be deemed to represent Debentures having an
aggregate principal amount equal to the aggregate stated liquidation amount of,
with an interest rate identical to the Coupon Rate of, and accrued and unpaid
interest (including Compound Interest (as defined in the Indenture)) equal to
accrued and unpaid Distributions on such Securities until such certificates are
presented to the Debenture Issuer or its agent for transfer or reissue.

     (d)  The Trust may not redeem fewer than all the outstanding Securities
unless all accrued and unpaid Distributions have been paid on all Securities for
all quarterly Distribution periods terminating on or prior to the date of
redemption.

     (e)  (i)  Notice of any redemption of, or notice of distribution of
     Debentures in exchange for, the Securities (a "Redemption/Distribution
     Notice") will be given by the Trust by mail to each Holder of Securities to
     be redeemed or exchanged not fewer than 30 nor more than 60 days before the
     date fixed for redemption or exchange thereof which, in the case of a
     redemption, will be the date fixed for redemption of the Debentures.  For
     purposes of the calculation of the date of redemption or exchange and the
     dates on which notices are given pursuant to this Section 4(e), a
     Redemption/Distribution Notice shall be deemed to be given on the day such
     notice is first mailed by first-class mail, postage prepaid, or by such
     other means suitable to assure delivery of such written notice, to Holders
     of Securities.  Each Redemption/Distribution Notice shall be addressed to
     the Holders of Securities at the address of each such Holder appearing in
     the books and records of the Trust.  No defect in the
     Redemption/Distribution Notice or in the mailing of either thereof with
     respect to any Holder of Securities shall affect the validity of the
     redemption or exchange proceedings with respect to any other Holder of
     Securities.

         (ii)  In addition to the Redemption/Distribution Notice to be
     provided to the Holders of Securities pursuant to clause (i) of this
     Section 4(e), the Debenture Issuer or the Trust shall give public notice of
     any such redemption by the issuance of a press release through the services
     of the Dow Jones Broad Tape, Reuters News Service and Bloomberg News
     Service.

     (f)  In the event that fewer than all the outstanding Securities are to be
redeemed, the Securities to be redeemed shall be redeemed Pro Rata from each
Holder of Convertible Preferred Securities, it being understood that, in respect
of Convertible Preferred Securities registered in the name of and held of record
by the Depository or its nominee (or any successor Clearing Agency or its
nominee) or any nominee, the distribution of the proceeds of such redemption
will be made to each Clearing Agency Participant (or Person on whose behalf such
nominee holds such securities) in accordance with the procedures applied by such
agency or nominee.

     (g)  If Securities are to be redeemed and the Trust gives a
Redemption/Distribution Notice, which notice may only be issued for a redemption
if the Debentures are redeemed as set out in Article X of the Indenture (which
notice will be irrevocable), then (i) with respect to Convertible Preferred
Securities held in book-entry form by 12:00 noon, New York City time, 

                                      I-7
<PAGE>
 
on the redemption date, provided that the Debenture Issuer has paid the
Institutional Trustee a sufficient amount of cash in connection with the related
redemption of the Debentures, the Institutional Trustee will deposit irrevocably
with the Depository or its nominee (or successor Clearing Agency or its nominee)
funds sufficient to pay the applicable Redemption Price with respect to such
Convertible Preferred Securities and will give the Depository irrevocable
instructions and authority to pay the Redemption Price to the Holders of such
Convertible Preferred Securities, and (ii) with respect to Convertible Preferred
Securities issued in definitive form and Common Securities, provided that the
Debenture Issuer has paid the Institutional Trustee a sufficient amount of cash
in connection with the related redemption of the Debentures, the Institutional
Trustee will pay the relevant Redemption Price to the Holders of such Securities
by check mailed to the address of the relevant Holder appearing on the books and
records of the Trust on the redemption date. If a Redemption/Distribution Notice
shall have been given in connection with a redemption and funds deposited as
required, then from and after the required date of such deposit, distributions
will cease to accrue on the Securities so called for redemption and all rights
of Holders of such Securities so called for redemption will cease, except the
right of the Holders of such Securities to receive the Redemption Price, but
without interest on such Redemption Price. If any date fixed for redemption of
Securities is not a Business Day, then payment of the Redemption Price payable
on such date will be made on the next succeeding Business Day (and without any
interest or other payment in respect of any such delay) except that, if such
Business Day falls in the next calendar year, such payment will be made on the
immediately preceding Business Day, in each case with the same force and effect
as if made on such date fixed for redemption. If payment of the Redemption Price
in respect of any Securities is improperly withheld or refused and not paid
either by the Institutional Trustee or by the Sponsor as guarantor pursuant to
the relevant Securities Guarantee, Distributions on such Securities will
continue to accrue from the original redemption date to the actual date of
payment, in which case the actual payment date will be considered the date fixed
for redemption for purposes of calculating the Redemption Price.

     Neither the Regular Trustees nor the Trust shall be required (i) in the
event of any redemption in part, to issue, register the transfer of or exchange
any Securities during a period beginning at the opening of business 15 days
before any selection for redemption of Securities and ending at the close of
business on the earliest date in which the relevant Redemption/Distribution
Notice is deemed to have been given to all holders of Securities to be so
redeemed or (ii) to register the transfer of or exchange any Securities selected
for redemption, in whole or in part, except for the unredeemed portion of any
Securities being redeemed in part.

     (h)  Redemption/Distribution Notices shall be sent by the Regular Trustees
on behalf of the Trust to (i) in respect of Convertible Preferred Securities
held in global form, the Depository or its nominee (or any successor Clearing
Agency or its nominee), (ii) with respect to Convertible Preferred Securities
held in definitive form, to the Holders thereof, and (iii) in respect of the
Common Securities, to the Holders thereof.

     (i)  Subject to the foregoing and applicable law (including, without
limitation, United States federal securities laws), the Sponsor or any of its
subsidiaries may at any time and from time to time purchase outstanding
Convertible Preferred Securities by tender, in the open market or otherwise.

                                      I-8
<PAGE>
 
     5.   Conversion Rights.
          ----------------- 

     The Holders of Securities shall have the right at any time, beginning May
21, 1997 through the close of business on May 28, 2027 (or, in the case of
Securities called for redemption, prior to the close of business on the
Business Day prior to the redemption date), at their option, to cause the
Conversion Agent to convert Securities, on behalf of the converting Holders,
into shares of Common Stock in the manner described herein on and subject to the
following terms and conditions:

     (a)  The Securities will be convertible at the office of the Conversion
Agent into fully paid and nonassessable shares of Common Stock pursuant to the
Holder's direction to the Conversion Agent to exchange such Securities for a
portion of the Debentures theretofore held by the Trust on the basis of one
Security per $50 principal amount of Debentures, and immediately convert such
amount of Debentures into fully paid and nonassessable shares of Common Stock at
an initial rate of .6709 shares of Common Stock per $50 principal amount of
Debentures (which is equivalent to a conversion price of $74.53 per share of
Common Stock, subject to certain adjustments set forth in Article XII of the
Indenture (as so adjusted, "Conversion Price")).

     (b)  In order to convert Securities into Common Stock, the Holder shall
submit to the Conversion Agent at its office an irrevocable request to convert
Securities on behalf of such Holder (the "Conversion Request"), together, if the
Securities are in certificated form, with such certificates.  The Conversion
Request shall (i) set forth the number of Securities to be converted and the
name or names, if other than the Holder, in which the shares of Common Stock
should be issued and (ii) direct the Conversion Agent (a) to exchange such
Securities for a portion of the Debentures held by the Trust (at the rate of
exchange specified in the preceding paragraph) and (b) to immediately convert
such Debentures on behalf of such Holder, into Common Stock (at the conversion
rate specified in the preceding paragraph).  The Conversion Agent shall notify
the Trust of the Holder's election to exchange Securities for a portion of the
Debentures held by the Trust and the Trust shall, upon receipt of such notice,
deliver to the Conversion Agent the appropriate principal amount of Debentures
for exchange in accordance with this Section.  The Conversion Agent shall
thereupon notify McKesson of the Holder's election to convert such Debentures
into shares of Common Stock.  Holders of Securities at the close of business on
a Distribution record date will be entitled to receive the Distribution payable
on such securities on the corresponding Distribution payment date
notwithstanding the conversion of such Securities following such record date but
prior to such distribution payment date; provided, however, that if the date of
any redemption of the related Debentures falls between such record date and the
related Distribution payment date, the amount of such Distribution shall include
accumulated and unpaid Distributions accrued to but excluding such date of
redemption, and such payment shall be made to the converting Holder.  Except as
provided above, neither the Trust nor the Sponsor will make, or be required to
make, any payment, allowance or adjustment upon any conversion on account of any
accumulated and unpaid Distributions accrued on the Securities (including any
Additional Amounts accrued thereon) surrendered for conversion, or on account of
any accumulated and unpaid dividends on the shares of Common Stock issued upon
such conversion, except to the extent that such shares are held of record on the
record date for any such distributions.  Securities shall be deemed to have been
converted immediately prior to the close of business on 

                                      I-9
<PAGE>
 
the day on which a Notice of Conversion relating to such Securities is received
by the Trust in accordance with the foregoing provision (the "Conversion Date").
The Person or Persons entitled to receive Common Stock issuable upon conversion
of the Debentures shall be treated for all purposes as the record holder or
holders of such Common Stock at such time. As promptly as practicable on or
after the Conversion Date, McKesson shall issue and deliver at the office of the
Conversion Agent a certificate or certificates for the number of full shares of
Common Stock issuable upon such conversion, together with the cash payment, if
any, in lieu of any fraction of any share to the Person or Persons entitled to
receive the same, unless otherwise directed by the Holder in the notice of
conversion and the Conversion Agent shall distribute such certificate or
certificates to such Person or Persons.

     (c)  Each Holder of a Security by his acceptance thereof appoints The First
National Bank of Chicago as "Conversion Agent" for the purpose of effecting the
conversion of Securities in accordance with this Section.  In effecting the
conversion and transactions described in this Section, the Conversion Agent
shall be acting as agent of the Holders of Securities directing it to effect
such conversion transactions.  The Conversion Agent is hereby authorized (i) to
exchange Securities from time to time for Debentures held by the Trust in
connection with the conversion of such Securities in accordance with this
Section and (ii) to convert all or a portion of the Debentures into Common Stock
and thereupon to deliver such shares of Common Stock in accordance with the
provisions of this Section and to deliver to the Trust a new Debenture or
Debentures for any resulting unconverted principal amount.

     (d)  No fractional shares of Common Stock will be issued as a result of
conversion of Securities, but in lieu thereof such fractional interest will be
paid in cash by McKesson, in an amount based on the Closing Price of the Common
Stock on the date such Securities are surrendered for conversion, to the
Conversion Agent, which in turn will make such payment to the Holder or Holders
of Securities so converted.

     (e)  McKesson shall at all times reserve and keep available out of its
authorized and unissued Common Stock, solely for issuance upon the conversion of
the Debentures, free from any preemptive or other similar rights, such number of
shares of Common Stock as shall from time to time be issuable upon the
conversion of all the Debentures then outstanding.  Notwithstanding the
foregoing, McKesson shall be entitled to deliver upon conversion of Debentures,
shares of Common Stock reacquired and held in the treasury of McKesson (in lieu
of the issuance of authorized and unissued shares of Common Stock), so long as
any such treasury shares are free and clear of all liens, charges, security
interests or encumbrances.  Any shares of Common Stock issued upon conversion of
the Debentures shall be duly authorized, validly issued and fully paid and
nonassessable.  The Trust shall deliver the shares of Common Stock received upon
conversion of the Debentures to the converting Holder free and clear of all
liens, charges, security interests and encumbrances, except for United States
withholding taxes.  Each of McKesson and the Trust shall prepare and shall use
its best efforts to obtain and keep in force such governmental or regulatory
permits or other authorizations as may be required by law, and shall comply with
all applicable requirements as to registration or qualification of Common Stock
(and all requirements to list Common Stock issuable upon conversion of
Debentures that are at the time applicable), in order to enable McKesson to
lawfully issue Common Stock to the Trust 

                                     I-10
<PAGE>
 
upon conversion of the Debentures and the Trust to lawfully deliver Common Stock
to each Holder upon conversion of the Securities.

     (f)  McKesson will pay any and all taxes that may be payable in respect of
the issue or delivery of shares of Common Stock on conversion of Debentures and
the delivery of the shares of Common Stock by the Trust upon conversion of the
Securities.  McKesson shall not, however, be required to pay any tax which may
be payable in respect of any transfer involved in the issue and delivery of
shares of Common Stock in a name other than that in which the Securities so
converted were registered, and no such issue or delivery shall be made unless
and until the person requesting such issue has paid to the Trust the amount of
any such tax, or has established to the satisfaction of the Trust that such tax
has been paid.

     (g)  Nothing in the preceding Paragraph (f) shall limit the requirement of
the Trust to withhold taxes pursuant to the terms of the Securities or as set
forth in this Annex I to the Declaration or to the Declaration itself or
otherwise require the Institutional Trustee or the Trust to pay any amounts on
account of such withholdings.

     (h)  The term "Closing Price" with respect to any security on any day means
the last reported sale price, regular way on such day, or, if no sale takes
place on such day, the average of the reported closing bid and asked prices on
such day, regular way, in either case as reported on the NYSE Composite Tape,
or, if such security is not listed or admitted to trading on the NYSE, on the
principal national securities exchange on which such security is listed or
admitted to trading, or, if such security is not listed or admitted to trading
on a national securities exchange, on the National Market System of the National
Association of Securities Dealers, Inc., or, if such security is not quoted or
admitted to trading on such quotation system, on the principal quotation system
on which such security is listed or admitted to trading or quoted, or, if not
listed or admitted to trading or quoted on any national securities exchange or
quotation system, the average of the closing bid and asked prices of such
security in the over-the-counter market on the day in question as reported by
the National Quotation Bureau Incorporated, or a similar generally  accepted
reporting service, or, if not so available in such manner, as furnished by any
NYSE member firm selected from time to time by the board of Directors (or any
committee duly authorized by the Board of Directors) of the Debenture Issuer for
that purpose or, if not so available in such manner, as otherwise determined in
good faith by the Board of Directors (or any committee duly authorized by the
Board of Directors) of the Debenture Issuer.

     6.   Voting and Other Rights - Convertible Preferred Securities.
          ---------------------------------------------------------- 

     (a)  Except as provided under Sections 6(b) and 8 of this Annex I to the
Declaration and as otherwise required by law and the Declaration, the Holders of
the Convertible Preferred Securities will not have voting rights.

     (b)  Subject to the requirements set forth in this paragraph, the Holders
of a Majority in liquidation amount of the Convertible Preferred Securities then
outstanding, voting separately as a class, may direct the time, method, and
place of conducting any proceeding for any remedy available to the Institutional
Trustee, or may direct the exercise of any trust or power conferred upon the
Institutional Trustee under the Declaration, including the right to direct the
Institutional 

                                     I-11
<PAGE>
 
Trustee, as holder of the Debentures, to (i) exercise the remedies available
under the Indenture with respect to the Debentures, (ii) waive any past default
and its consequences that is waivable under Section 5.9 of the Indenture, or
(iii) exercise any right to rescind or annul a declaration that the principal of
all the Debentures shall be due and payable, provided, however, that if an Event
of Default under the Indenture has occurred and is continuing then the holders
of 25% of the aggregate liquidation amount of the Convertible Preferred
Securities then outstanding may direct the Institutional Trustee to declare the
principal of and interest on the Debentures immediately due and payable; and
provided, further, that, where a consent under the Indenture would require the
consent or act of the Holders of greater than a majority of the Holders in
principal amount of Debentures then outstanding (a "Super Majority") affected
thereby, the Institutional Trustee may only give such consent or take such
action at the written direction of the Holders of at least the proportion in
liquidation amount of the Convertible Preferred Securities which the relevant
Super Majority represents of the aggregate principal amount of the Debentures
then outstanding. The Institutional Trustee shall not revoke any action
previously authorized or approved by a vote of the Holders of the Convertible
Preferred Securities. Other than with respect to directing the time, method and
place of conducting any remedy available to the Institutional Trustee as set
forth above, the Institutional Trustee shall not take any action in accordance
with the directions of the Holders of the Convertible Preferred Securities under
this paragraph unless the Institutional Trustee has obtained an opinion of
nationally recognized independent tax counsel experienced in such matters to the
effect that for the purposes of United States federal income tax the Trust will
not be classified as other than a grantor trust as a result of such action. If
the Institutional Trustee fails to enforce its rights under the Debentures, any
Holder of Convertible Preferred Securities may institute a legal proceeding
against any person to enforce the Institutional Trustee's rights under the
Debentures. If a Declaration Event of Default has occurred and is continuing and
such event is attributable to the failure of the Debenture Issuer to pay
interest or principal on the Debentures on the date such interest or principal
is otherwise payable (or in the case of redemption, on the redemption date),
then a Holder of Convertible Preferred Securities may directly institute a
proceeding for enforcement of payment to such Holder of the principal of or
interest on the Debentures having a principal amount equal to the aggregate
liquidation amount of the Convertible Preferred Securities of such Holder (a
"Direct Action") on or after the respective due date specified in the
Debentures. In connection with such Direct Action, the rights of the Holders of
Common Securities will be subrogated to the rights of such Holder of Convertible
Preferred Securities to the extent of any payment made by the Issuer to such
Holder of Convertible Preferred Securities in such Direct Action. Except as
provided in the preceding sentences, the Holders of Convertible Preferred
Securities will not be able to exercise directly any other remedy available to
the holders of the Debentures.

     Any approval or direction of Holders of Convertible Preferred Securities
may be given at a separate meeting of Holders of Convertible Preferred
Securities convened for such purpose, at a meeting of all of the Holders of
Securities in the Trust or pursuant to written consent.  The Regular Trustees
will cause a notice of any meeting at which Holders of Convertible Preferred
Securities are entitled to vote, or of any matter upon which action by written
consent of such Holders is to be taken, to be mailed to each Holder of record of
Convertible Preferred Securities.  Each such notice will include a statement
setting forth (i) the date of such meeting or the date by which such action is
to be taken, (ii) a description of any resolution proposed for 

                                     I-12
<PAGE>
 
adoption at such meeting on which such Holders are entitled to vote or of such
matter upon which written consent is sought and (iii) instructions for the
delivery of proxies or consents.

     No vote or consent of the Holders of the Convertible Preferred Securities
will be required for the Trust to redeem and cancel Convertible Preferred
Securities or to distribute the Debentures in accordance with the Declaration
and the terms of the Securities.

     Notwithstanding that Holders of Convertible Preferred Securities are
entitled to vote or consent under any of the circumstances described above, any
of the Convertible Preferred Securities that are owned by the Sponsor or any
Affiliate of the Sponsor shall not be entitled to vote or consent and shall, for
purposes of such vote or consent, be treated as if they were not outstanding.

     7.   Voting Rights - Common Securities.
          --------------------------------- 

     (a)  Except as provided under Sections 7(b), 7(c) and 8 of this Annex I of
the Declaration and as otherwise required by law and the Declaration, the
Holders of the Common Securities will not have voting rights.

     (b)  The Holders of the Common Securities are entitled, in accordance with
Article V of the Declaration, to vote to appoint, remove or replace any Trustee
or to increase or decrease the number of Trustees.

     (c)  Subject to Section 2.6 of the Declaration and only after any Event of
Default with respect to the Convertible Preferred Securities has been cured,
waived, or otherwise eliminated and subject to the requirements of the second to
last sentence of this paragraph, the Holders of a Majority in liquidation amount
of the Common Securities, voting separately as a class, may direct the time,
method, and place of conducting any proceeding for any remedy available to the
Institutional Trustee, or exercising any trust or power conferred upon the
Institutional Trustee under the Declaration, including (i) directing the time,
method, place of conducting any proceeding for any remedy available to the
Debenture Trustee, or exercising any trust or power conferred on the Debenture
Trustee with respect to the Debentures, (ii) waive any past default and its
consequences that is waivable under Section 5.9 of the Indenture, or (iii)
exercise any right to rescind or annul a declaration that the principal of all
the Debentures shall be due and payable, provided that, where a consent or
action under the Indenture would require the consent or act of the relevant
Super Majority, the Institutional Trustee may only give such consent or take
such action at the written direction of the Holders of at least the proportion
in liquidation amount of the Common Securities which the relevant Super Majority
represents of the aggregate principal amount of the Debentures outstanding.  The
Institutional Trustee shall not revoke any action previously authorized or
approved by a vote of the Holders of the Convertible Preferred Securities.
Other than with respect to directing the time, method and place of conducting
any remedy available to the Institutional Trustee or the Debenture Trustee as
set forth above, the Institutional Trustee shall not take any action in
accordance with the directions of the Holders of the Common Securities under
this paragraph unless the Institutional Trustee has obtained an opinion of
nationally recognized independent tax counsel experienced in such matters to the
effect that for the purposes of United States federal income tax the Trust will
not be classified 

                                     I-13
<PAGE>
 
as other than a grantor trust on account of such action. If the Institutional
Trustee fails to enforce its rights under the Declaration, any Holder of Common
Securities may institute a legal proceeding directly against any Person to
enforce the Institutional Trustee's rights under the Declaration, without first
instituting a legal proceeding against the Institutional Trustee or any other
Person.

     Any approval or direction of Holders of Common Securities may be given at a
separate meeting of Holders of Common Securities convened for such purpose, at a
meeting of all of the Holders of Securities in the Trust or pursuant to written
consent.  The Regular Trustees will cause a notice of any meeting at which
Holders of Common Securities are entitled to vote, or of any matter upon which
action by written consent of such Holders is to be taken, to be mailed to each
Holder of record of Common Securities.  Each such notice will include a
statement setting forth (i) the date of such meeting or the date by which such
action is to be taken, (ii) a description of any resolution proposed for
adoption at such meeting on which such Holders are entitled to vote or of such
matter upon which written consent is sought and (iii) instructions for the
delivery of proxies or consents.

     No vote or consent of the Holders of the Common Securities will be required
for the Trust to redeem and cancel Common Securities or to distribute the
Debentures in accordance with the Declaration and the terms of the Securities.

     8.   Amendments to Declaration and Indenture.
          --------------------------------------- 

     (a)  In addition to any requirements under Section 12.1 of the Declaration,
if any proposed amendment to the Declaration provides for, or the Regular
Trustees otherwise propose to effect, (i) any action that would adversely affect
the powers, preferences or special rights of the Securities, whether by way of
amendment to the Declaration or otherwise, or (ii) the dissolution, winding-up
or termination of the Trust, other than as described in Section 8.1 of the
Declaration, then the Holders of outstanding Securities voting together as a
single class, will be entitled to vote on such amendment or proposal (but not on
any other amendment or proposal) and such amendment or proposal shall not be
effective except with the approval of the Holders of at least a Majority in
liquidation amount of the Securities then outstanding affected thereby;
provided, however, if any amendment or proposal referred to in clause (i) above
would adversely affect only the Convertible Preferred Securities or only the
Common Securities, then only the affected class will be entitled to vote on such
amendment or proposal and such amendment or proposal shall not be effective
except with the approval of a Majority in liquidation amount of such class of
Securities then outstanding.

     (b)  In the event the consent of the Institutional Trustee as the holder of
the Debentures is required under the Indenture with respect to any amendment,
modification or termination of the Indenture or the Debentures, the
Institutional Trustee shall request the written direction of the Holders of the
Securities with respect to such amendment, modification or termination and shall
vote with respect to such amendment, modification or termination as directed by
a Majority in liquidation amount of the Securities then outstanding, voting
together as a single class; provided, however, that where a consent under the
Indenture would require the consent of the relevant Super Majority, the
Institutional Trustee may only give such consent at the direction 

                                     I-14
<PAGE>
 
of the Holders of at least the proportion in liquidation amount of the
Securities then outstanding which the relevant Super Majority represents of the
aggregate principal amount of the Debentures then outstanding; provided,
further, that the Institutional Trustee shall not take any action in accordance
with the directions of the Holders of the Securities under this Section 8(b)
unless the Institutional Trustee has obtained an opinion of nationally
recognized independent tax counsel experienced in such matters to the effect
that for the purposes of United States federal income tax the Trust will not be
classified as other than a grantor trust as a result of such action.

     9.   Pro Rata.
          -------- 

     A reference in these terms of the Securities to any distribution or
treatment as being "Pro Rata" shall mean pro rata to each Holder of Securities
according to the aggregate liquidation amount of the Securities held by the
relevant Holder in relation to the aggregate liquidation amount of all
Securities outstanding unless, in relation to a payment, an Event of Default
under the Declaration has occurred and is continuing, in which case any funds
available to make such payment shall be paid first in cash to each Holder of the
Convertible Preferred Securities pro rata according to the aggregate liquidation
amount of Convertible Preferred Securities held by the relevant Holder relative
to the aggregate liquidation amount of all Convertible Preferred Securities
outstanding, and only after satisfaction of all amounts owed to the Holders of
the Convertible Preferred Securities, to each Holder of Common Securities pro
rata according to the aggregate liquidation amount of Common Securities held by
the relevant Holder relative to the aggregate liquidation amount of all Common
Securities outstanding.

     10.  Ranking.
          ------- 

     The Convertible Preferred Securities rank pari passu and payment thereon
shall be made Pro Rata with the Common Securities except that, where a
Declaration Event of Default occurs and is continuing, the rights of Holders of
the Common Securities to payment in respect of Distributions and payments upon
liquidation, redemption and otherwise are subordinated to the rights to payment
of the Holders of the Convertible Preferred Securities.

     11.  Acceptance of Securities Guarantee and Indenture.
          ------------------------------------------------ 

     Each Holder of Convertible Preferred Securities and Common Securities, by
the acceptance thereof, agrees to the provisions of the Convertible Preferred
Securities Guarantee and the Common Securities Guarantee, respectively,
including the subordination provisions therein and to the provisions of the
Indenture.

     12.  No Preemptive Rights.
          -------------------- 

     The Holders of the Securities shall have no preemptive rights to subscribe
for any additional securities.

                                     I-15
<PAGE>
 
     13.  Miscellaneous.
          ------------- 

     These terms constitute a part of the Declaration.The Sponsor will provide a
copy of the Declaration, the Convertible Preferred Securities Guarantee or the
Common Securities Guarantee (as may be appropriate), and the Indenture to a
Holder without charge on written request to the Sponsor at its principal place
of business.

                                     I-16
<PAGE>
 
                                  EXHIBIT A-1

             [FORM OF CONVERTIBLE PREFERRED SECURITY CERTIFICATE]


     [IF THE CONVERTIBLE PREFERRED SECURITY IS TO BE A GLOBAL CERTIFICATE INSERT
- - - THIS CONVERTIBLE PREFERRED SECURITY IS A GLOBAL CERTIFICATE WITHIN THE MEANING
OF THE DECLARATION HEREIN AFTER REFERRED TO AND IS REGISTERED IN THE NAME OF THE
DEPOSITORY TRUST COMPANY (THE "DEPOSITARY") OR A NOMINEE OF THE DEPOSITARY.
THIS CONVERTIBLE PREFERRED SECURITY IS EXCHANGEABLE FOR CONVERTIBLE PREFERRED
SECURITIES REGISTERED IN THE NAME OF A PERSON OTHER THAN THE DEPOSITARY OR ITS
NOMINEE ONLY IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE DECLARATION AND NO
TRANSFER OF THIS CONVERTIBLE PREFERRED SECURITY (OTHER THAN A TRANSFER OF THIS
CONVERTIBLE PREFERRED SECURITY AS A WHOLE BY THE DEPOSITARY TO A NOMINEE OF THE
DEPOSITARY OR BY A NOMINEE OF THE DEPOSITARY TO THE DEPOSITARY OR ANOTHER
NOMINEE OF THE DEPOSITARY) MAY BE REGISTERED EXCEPT IN LIMITED CIRCUMSTANCES.

     UNLESS THIS CONVERTIBLE PREFERRED SECURITY IS PRESENTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY (55 WATER STREET, NEW YORK, NEW
YORK) TO THE TRUST OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR
PAYMENT, AND ANY CONVERTIBLE PREFERRED SECURITY ISSUED IS REGISTERED IN THE
NAME OF CEDE & CO.  OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED 
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT HEREON IS MADE TO
CEDE & CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY A
PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
INTEREST HEREIN.]

CERTIFICATE NUMBER:

NUMBER OF CONVERTIBLE PREFERRED SECURITIES:

CUSIP NO.:  [IF RULE 144A - 58155P204] [IF INSTITUTIONAL ACCREDITED INVESTOR -
58155P303] [IF REGULATION S - U58088102]

[ISIN NO.:  USU580881022 - ONLY IF REGULATION S]

[COMMON CODE:  . - ONLY IF REGULATION S]

                                     A1-1
<PAGE>
 
            Certificate Evidencing Convertible Preferred Securities

                                      of

                           McKESSON FINANCING TRUST

     [PRIOR TO THE TRANSFER RESTRICTION TERMINATION DATE, ANY CERTIFICATE
     EVIDENCING A CONVERTIBLE PREFERRED SECURITY SHALL BEAR A LEGEND IN
     SUBSTANTIALLY THE FOLLOWING FORM, UNLESS OTHERWISE AGREED BY THE REGULAR
     TRUSTEES (WITH WRITTEN NOTICE TO THE INSTITUTIONAL TRUSTEE): THE SECURITY
     EVIDENCED HEREBY HAS NOT BEEN REGISTERED UNDER THE U.S. SECURITIES ACT OF
     1933, AS AMENDED (THE "SECURITIES ACT"), AND, ACCORDINGLY, MAY NOT BE
     OFFERED OR SOLD WITHIN THE UNITED STATES OR TO, OR FOR THE ACCOUNT OR
     BENEFIT OF, U.S. PERSONS EXCEPT AS SET FORTH IN THE FOLLOWING SENTENCE. BY
     ITS ACQUISITION HEREOF, THE HOLDER (1) REPRESENTS THAT (A) IT IS A
     "QUALIFIED INSTITUTIONAL BUYER" (AS DEFINED IN RULE 144A UNDER THE
     SECURITIES ACT) OR (B) IT IS AN INSTITUTIONAL "ACCREDITED INVESTOR" (AS
     DEFINED IN RULE 501(A)(1), (2), (3) OR (7) UNDER THE SECURITIES ACT)
     ("INSTITUTIONAL ACCREDITED INVESTOR") OR (C) IT IS NOT A U.S. PERSON AND IS
     ACQUIRING THE SECURITY EVIDENCED HEREBY IN AN OFFSHORE TRANSACTION, (2)
     AGREES THAT IT WILL NOT PRIOR TO THE EXPIRATION OF THE HOLDING PERIOD
     APPLICABLE TO SALES OF THE SECURITY EVIDENCED HEREBY UNDER RULE 144(K)
     UNDER THE SECURITIES ACT (OR ANY SUCCESSOR PROVISION) RESELL OR OTHERWISE
     TRANSFER THE SECURITY EVIDENCED HEREBY OR IF THIS SECURITY IS CONVERTIBLE
     INTO COMMON STOCK THE COMMON STOCK ISSUABLE UPON CONVERSION OR EXCHANGE OF
     THIS SECURITY EXCEPT (A) TO McKESSON CORPORATION (THE "COMPANY") OR ANY
     SUBSIDIARY THEREOF, (B) PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT
     UNDER THE SECURITIES ACT, (C) TO A QUALIFIED INSTITUTIONAL BUYER IN
     COMPLIANCE WITH RULE 144A UNDER THE SECURITIES ACT, (D) TO AN INSTITUTIONAL
     ACCREDITED INVESTOR THAT, PRIOR TO SUCH TRANSFER, FURNISHES TO THE TRUSTEE
     FOR THE CONVERTIBLE PREFERRED SECURITIES OR THE CONVERTIBLE DEBENTURES, AS
     THE CASE MAY BE (OR, IF THIS CERTIFICATE EVIDENCES COMMON STOCK, THE
     TRANSFER AGENT FOR THE COMMON STOCK), A SIGNED LETTER CONTAINING CERTAIN
     REPRESENTATIONS AND AGREEMENTS RELATING TO THE RESTRICTIONS ON TRANSFER OF
     THE SECURITY EVIDENCED HEREBY (THE FORM OF WHICH LETTER CAN BE OBTAINED
     FROM SUCH TRUSTEE OR TRANSFER AGENT), (E) OUTSIDE THE UNITED STATES IN
     COMPLIANCE WITH RULE 904 UNDER THE SECURITIES ACT OR (F) PURSUANT TO THE
     EXEMPTION FROM REGISTRATION PROVIDED BY RULE 144 UNDER THE SECURITIES ACT
     (IF AVAILABLE) AND (3) AGREES

                                     A1-2
<PAGE>
 
     THAT IT WILL DELIVER TO EACH PERSON TO WHOM THE SECURITY EVIDENCED HEREBY
     IS TRANSFERRED A NOTICE SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND. IN
     CONNECTION WITH ANY TRANSFER OF THE SECURITY EVIDENCED HEREBY PRIOR TO
     EXPIRATION OF THE HOLDING PERIOD APPLICABLE TO SALES OF THE SECURITY
     EVIDENCED HEREBY UNDER RULE 144(K) UNDER THE SECURITIES ACT (OR ANY
     SUCCESSOR PROVISION), THE HOLDER MUST CHECK THE APPROPRIATE BOX SET FORTH
     ON THE REVERSE HEREOF RELATING TO THE MANNER OF SUCH TRANSFER AND SUBMIT
     THIS CERTIFICATE TO THE TRUSTEE FOR THE CONVERTIBLE PREFERRED SECURITIES OR
     THE CONVERTIBLE DEBENTURES, AS THE CASE MAY BE (OR, IF THIS CERTIFICATE
     EVIDENCES COMMON STOCK, SUCH HOLDER MUST FURNISH TO THE TRANSFER AGENT SUCH
     CERTIFICATIONS, LEGAL OPINIONS OR OTHER INFORMATION AS THE COMPANY OR
     McKESSON FINANCIAL TRUST (THE "TRUST") MAY REASONABLY REQUIRE TO CONFIRM
     THAT SUCH TRANSFER IS BEING MADE PURSUANT TO AN EXEMPTION FROM, OR IN A
     TRANSACTION NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE SECURITIES
     ACT). IF THIS CERTIFICATE DOES NOT EVIDENCE COMMON STOCK AND IF THE
     PROPOSED TRANSFEREE IS AN INSTITUTIONAL ACCREDITED INVESTOR OR A PURCHASER
     WHO IS NOT A U.S. PERSON, THE HOLDER MUST, PRIOR TO SUCH TRANSFER, FURNISH
     TO THE TRUSTEE FOR THE CONVERTIBLE PREFERRED SECURITIES OR THE CONVERTIBLE
     DEBENTURES, AS THE CASE MAY BE, SUCH CERTIFICATIONS, LEGAL OPINIONS OR
     OTHER INFORMATION AS THE COMPANY OR THE TRUST MAY REASONABLY REQUIRE TO
     CONFIRM THAT SUCH TRANSFER IS BEING MADE PURSUANT TO AN EXEMPTION FROM, OR
     IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE
     SECURITIES ACT. THIS LEGEND WILL BE REMOVED AFTER THE EXPIRATION OF THE
     HOLDING PERIOD APPLICABLE TO SALES OF THE SECURITY EVIDENCED HEREBY UNDER
     RULE 144(K) UNDER THE SECURITIES ACT. AS USED HEREIN, THE TERMS "OFFSHORE
     TRANSACTION," "UNITED STATES" AND "U.S. PERSON" HAVE THE MEANINGS GIVEN TO
     THEM BY REGULATION S UNDER THE SECURITIES ACT.]

     5% Trust Convertible Preferred Securities (liquidation amount $50 per Trust
Convertible Preferred Security)

     McKesson Financing Trust, a statutory business trust formed under the laws
of the State of Delaware (the "Trust"), hereby certifies that __________________
(the "Holder") is the registered owner of convertible preferred securities of
the Trust representing undivided beneficial interests in the assets of the Trust
designated the 5% Trust Convertible Preferred Securities (liquidation amount $50
per Trust Convertible Preferred Security) (the "Convertible Preferred
Securities"). The Convertible Preferred Securities are transferable on the books
and records of the Trust, in person or by a duly authorized attorney, upon
surrender of this certificate duly endorsed and in proper form for transfer.

                                     A1-3
<PAGE>
 
     The designation, rights, privileges, restrictions, preferences and other
terms and provisions of the Convertible Preferred Securities represented hereby
are issued and shall in all respects be subject to the provisions of the Amended
and Restated Declaration of Trust of the Trust dated as of February 20, 1997, as
the same may be amended from time to time (the "Declaration"), including the
designation of the terms of the Convertible Preferred Securities as set forth in
Annex I to the Declaration.

     Capitalized terms used herein but not defined shall have the meaning given
them in the Declaration. The Holder is entitled to the benefits of the
Convertible Preferred Securities Guarantee to the extent provided therein. The
Sponsor will provide a copy of the Declaration, the Convertible Preferred
Securities Guarantee and the Indenture to the Holder without charge upon written
request to the Trust at its principal place of business.

     Upon receipt of this certificate, the Holder is bound by the Declaration
and is entitled to the benefits thereunder.

     By acceptance, the Holder agrees to treat, for United States federal income
tax purposes, the Debentures as indebtedness and the Convertible Preferred
Securities as evidence of indirect beneficial ownership in the Debentures.

     Unless the Institutional Trustee's Certificate of Authentication hereon has
been properly executed, these Convertible Preferred Securities shall not be
entitled to any benefit under the Declaration or be valid or obligatory for any
purpose.

                                     A1-4
<PAGE>
 
     IN WITNESS WHEREOF, the Trust has executed this certificate this 20th day
of February, 1997.

                                   McKesson Financing Trust


                                   By: ____________________________________
                                       Name:
                                       Title: Trustee
                                       Solely as trustee and not in his 
                                       individual capacity

                                     A1-5
<PAGE>
 
                    [FORM OF CERTIFICATE OF AUTHENTICATION]

             INSTITUTIONAL TRUSTEE'S CERTIFICATE OF AUTHENTICATION

     This is one of the Convertible Preferred Securities referred to in the
within-mentioned Declaration.

Dated:  February 20, 1997

THE FIRST NATIONAL BANK OF CHICAGO,
as Institutional Trustee                     or as Authentication Agent
 
By: _______________________________          By: _______________________________
    Authorized Signatory                         Authorized Signatory

                                     A1-6
<PAGE>
 
                         [FORM OF REVERSE OF SECURITY]

     Distributions payable on each Convertible Preferred Security will be fixed
at a rate per annum of 5% (the "Coupon Rate") of the stated liquidation amount
of $50 per Preferred Security, such rate being the rate of interest payable on
the Debentures to be held by the Institutional Trustee. Distributions in arrears
for more than one quarter will bear interest thereon compounded quarterly at the
Coupon Rate (to the extent permitted by applicable law). The term
"Distributions" as used herein includes such cash distributions and any such
interest payable unless otherwise stated. A Distribution is payable only to the
extent that payments are made in respect of the Debentures held by the
Institutional Trustee and to the extent the Institutional Trustee has funds
available therefor. The amount of Distributions payable for any period will be
computed for any full quarterly Distribution period on the basis of a 360-day
year of twelve 30-day months, and for any period shorter than a full quarterly
Distribution period for which Distributions are computed, Distributions will be
computed on the basis of the actual number of days elapsed per 30-day month.

     Except as otherwise described below, Distributions on the Convertible
Preferred Securities will be cumulative, will accrue from February 20, 1997 and
will be payable quarterly in arrears, on March 1, June 1, September 1 and
December 1 of each year, commencing on June 1, 1997, which payment dates shall
correspond to the interest payment dates on the Debentures, to Holders of record
at the close of business on the regular record date for such Distribution which
shall be the close of business 15 days prior to such Distribution payment date
unless otherwise provided in the Declaration. The Debenture Issuer has the right
under the Indenture to defer payments of interest by extending the interest
payment period from time to time on the Debentures for a period not exceeding 20
consecutive quarters (each an "Extension Period"); provided that no Extension
Period shall last beyond the date of the maturity or any redemption date of the
Debentures and, as a consequence of such deferral, Distributions will also be
deferred. Despite such deferral, quarterly Distributions will continue to accrue
with interest thereon (to the extent permitted by applicable law) at the Coupon
Rate compounded quarterly during any such Extension Period. Prior to the
termination of any such Extension Period, the Debenture Issuer may further
extend such Extension Period; provided that such Extension Period together with
all such previous and further extensions thereof may not exceed 20 consecutive
quarters or extend beyond the maturity or any redemption date of the Debentures.
Upon the termination of any Extension Period and the payment of all amounts then
due, the Debenture Issuer may commence a new Extension Period, subject to the
above requirements.

     The Convertible Preferred Securities shall be redeemable as provided in the
Declaration.

     The Convertible Preferred Securities shall be convertible into shares of
Common Stock, through (i) the exchange of Convertible Preferred Securities for a
portion of the Debentures and (ii) the immediate conversion of such Debentures
into Debenture Issuer Common Stock, in the manner and according to the terms set
forth in the Declaration.

                                     A1-7
<PAGE>
 
                              CONVERSION REQUEST


To:  The First National Bank of Chicago,
     as Institutional Trustee of McKesson Financing Trust

     The undersigned owner of these Convertible Preferred Securities hereby
irrevocably exercises the option to convert these Convertible Preferred
Securities, or the portion below designated, into Common Stock of McKesson
Corporation (the "Common Stock") in accordance with the terms of the Amended and
Restated Declaration of Trust (the "Declaration"), dated as of February 20,
1997, by William A. Armstrong and Ivan D. Meyerson, as Regular Trustees, First
Chicago Delaware Inc., as Delaware Trustee, The First National Bank of Chicago,
as Institutional Trustee, McKesson Corporation, as Sponsor, and by the Holders,
from time to time, of individual beneficial interests in the Trust to be issued
pursuant to the Declaration. Pursuant to the afore mentioned exercise of the
option to convert these Convertible Preferred Securities, the undersigned
hereby directs the Conversion Agent (as that term is defined in the Declaration)
to (i) exchange such Convertible Preferred Securities for a portion of the
Debentures (as that term is defined in the Declaration) held by the Trust (at
the rate of exchange specified in the terms of the Convertible Preferred
Securities set forth as Annex I to the Declaration) and (ii) immediately convert
such Debentures on behalf of the undersigned, into Common Stock (at the
conversion rate specified in the terms of the Convertible Preferred Securities
set forth as Annex I to the Declaration).

     The undersigned does also hereby direct the Conversion Agent that the
shares issuable and deliverable upon conversion, together with any check in
payment for fractional shares, be issued in the name of and delivered to the
undersigned, unless a different name has been indicated in the assignment below.
If shares are to be issued in the name of a person other than the undersigned,
the undersigned will pay all transfer taxes payable with respect thereto.

                                     A1-8
<PAGE>
 
Date: _______________, ____

                              in whole _____           in part _____

                              Number of Convertible Preferred Securities to be
                              converted:  ____________________

                              If a name or names other than the undersigned,
                              please indicate in the spaces below the name or
                              names in which the shares of Common Stock are to
                              be issued, along with the address or addresses of
                              such person or persons


                              __________________________________________________
                              __________________________________________________
                              __________________________________________________
                              __________________________________________________
                              __________________________________________________


                              __________________________________________________
                              Signature (for conversion only)

                              Please Print or Typewrite Name and Address,
                              Including Zip Code, and Social Security or Other
                              Identifying Number

                              __________________________________________________
                              __________________________________________________
                              __________________________________________________

                              Signature Guarantee:/*/ __________________________


____________________

     /*/(Signature must be guaranteed by an "eligible guarantor institution,"
that is, a bank, stockbroker, savings and loan association or credit union
meeting the requirements of the Conversion Agent, which requirements include
membership or participation in the Securities Transfer Agents Medallion Program
("STAMP") or such other "signature guarantee program" as may be determined by
the Conversion Agent in addition to, or in substitution for, STAMP, all in
accordance with the Securities Exchange Act of 1934, as amended.)

                                     A1-9
<PAGE>
 
                [FORM OF ASSIGNMENT FOR DEFINITIVE CONVERTIBLE
                              PREFERRED SECURITY]

For value received ______________________ hereby sell(s), assign(s) and
transfer(s) unto _______________________________________________________________
   (Please insert social security or other taxpayer identification number of
                                   assignee.)

the within security and hereby irrevocably constitutes and appoints ____________
attorney to transfer the said security on the books of the Company, with full
power of substitution in the premises.

In connection with any transfer of the within security occurring prior to the
Transfer Restriction Termination Date, the undersigned confirms that such
security is being transferred:

     [_]  To McKesson Corporation or a subsidiary thereof; or

     [_]  Pursuant to and in compliance with Rule 144A under the Securities Act
          of 1933, as amended; or

     [_]  To an Institutional Accredited Investor pursuant to and in compliance
          with the Securities Act of 1933, as amended; or

     [_]  Pursuant to and in compliance with Regulation S under the Securities
          Act of 1933, as amended; or

     [_]  Pursuant to and in compliance with Rule 144 under the Securities Act
          of 1933, as amended; or

     [_]  Pursuant to an effective registration statement.

                                     A1-10
<PAGE>
 
and unless the box below is checked, the undersigned confirms that such security
is not being transferred to an "affiliate" of the Company as defined in Rule 144
under the Securities Act of 1933, as amended (an "Affiliate"):

     [_]  The transferee is an Affiliate of the Company.


Dated: ___________________________
 
Signature(s)
                                         ______________________________________

 
                                         ______________________________________


                                         ______________________________________
                                         Signature Guarantee/*/


NOTICE:  The above signatures of the holder(s) hereof must correspond with the
name as written upon the face of this Security in every particular without
alteration or enlargement or any change whatever.

___________________

     /*/ (Signature must be guaranteed by an "eligible guarantor institution,"
that is, a bank, stockbroker, savings and loan association or credit union
meeting the requirements of the Conversion Agent, which requirements include
membership or participation in the Securities Transfer Agents Medallion Program
("STAMP") or such other "signature guarantee program" as may be determined by
the Conversion Agent in addition to, or in substitution for, STAMP, all in
accordance with the Securities Exchange Act of 1934, as amended.)

                                     A1-11
<PAGE>
 
                                                                      SCHEDULE I

             CHANGES TO NUMBER OF CONVERTIBLE PREFERRED SECURITIES
                              IN GLOBAL SECURITY

<TABLE>
<CAPTION>
              Number of Convertible    
             Preferred Securities by  
                which this Global                                    
                Security Is To Be     Remaining Convertible          
              Reduced or Increased,    Preferred Securities          
                 and Reason for        Represented by this     
   Date       Reduction or Increase      Global Security       Notation Made By  
- - ----------   -----------------------  ---------------------   ------------------
<S>          <C>                      <C>                     <C>
 
</TABLE> 
 
                                     A1-12
<PAGE>
 
                                  EXHIBIT A-2

                      FORM OF COMMON SECURITY CERTIFICATE


CERTIFICATE NUMBER:

NUMBER OF COMMON SECURITIES:

                   Certificate Evidencing Common Securities

                                      of

                           McKESSON FINANCING TRUST

                             5% Common Securities
                 (liquidation amount $50 per Common Security)

     THE SECURITY EVIDENCED HEREBY HAS NOT BEEN REGISTERED UNDER THE U.S.
     SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND,
     ACCORDINGLY, MAY NOT BE OFFERED OR SOLD UNLESS SUCH OFFER AND SALE ARE
     REGISTERED UNDER OR ARE EXEMPT FROM REGISTRATION UNDER THE SECURITIES
     ACT. THE TRANSFER OF THE SECURITY EVIDENCED HEREBY IS ALSO SUBJECT TO
     THE RESTRICTIONS SET FORTH IN THE DECLARATION REFERRED TO BELOW.

     McKesson Financing Trust, a statutory business trust formed under the laws
of the State of Delaware (the "Trust"), hereby certifies that
________________________________________ (the "Holder") is the registered owner
of common securities of the Trust representing undivided beneficial interests in
the assets of the Trust designated the 5% Common Securities (liquidation amount
$50 per Common Security) (the "Common Securities"). The Common Securities are
transferable on the books and records of the Trust, in person or by a duly
authorized attorney, upon surrender of this certificate duly endorsed and in
proper form for transfer.

     The designation, rights, privileges, restrictions, preferences and other
terms and provisions of the Common Securities represented hereby are issued and
shall in all respects be subject to the provisions of the Amended and Restated
Declaration of Trust of the Trust dated as of February 20, 1997, as the same may
be amended from time to time (the "Declaration"), including the designation of
the terms of the Common Securities as set forth in Annex I to the Declaration.

     Capitalized terms used herein but not defined shall have the meaning given
them in the Declaration. The Holder is entitled to the benefits of the Common
Securities Guarantee to the extent provided therein. The Sponsor will provide a
copy of the Declaration, the Common 

                                     A2-1
<PAGE>
 
Securities Guarantee and the Indenture to a Holder without charge upon written
request to the Trust at its principal place of business.

     Upon receipt of this certificate, the Holder is bound by the Declaration
and is entitled to the benefits thereunder.

     By acceptance, the Holder agrees to treat, for United States federal income
tax purposes, the Debentures as indebtedness and the Common Securities as
evidence of indirect beneficial ownership in the Debentures.

                                     A2-2
<PAGE>
 
     IN WITNESS WHEREOF, the Trust has executed this certificate this 20th day
of February, 1997.

                              McKesson Financing Trust


                              By: ____________________________________________
                                  Name:
                                  Title: Trustee
                                  Solely as trustee and not in his individual 
                                  capacity

                                     A2-3
<PAGE>
 
                         [FORM OF REVERSE OF SECURITY]

     Distributions payable on each Common Security will be fixed at a rate per
annum, of 5% (the "Coupon Rate") of the stated liquidation amount of $50 per
Common Security, such rate being the rate of interest payable on the Debentures
to be held by the Institutional Trustee. Distributions in arrears for more than
one quarter will bear interest thereon compounded quarterly at the Coupon Rate
(to the extent permitted by applicable law). The term "Distributions" as used
herein includes such cash distributions and any such interest payable unless
otherwise stated. A Distribution is payable only to the extent that payments are
made in respect of the Debentures held by the Institutional Trustee and to the
extent the Institutional Trustee has funds available therefor. The amount of
Distributions payable for any period will be computed for any full quarterly
Distribution period on the basis of a 360-day year of twelve 30-day months, and
for any period shorter than a full quarterly Distribution period for which
Distributions are computed, Distributions will be computed on the basis of the
actual number of days elapsed per 30-day month.

     Except as otherwise described below, Distributions on the Common Securities
will be cumulative, will accrue from February 20, 1997 and will be payable
quarterly in arrears, on March 1, June 1, September 1 and December 1 of each
year, commencing on June 1, 1997, which payment dates shall correspond to the
interest payment dates on the Debentures, to Holders of record at the close of
business on the regular record date for such Distribution which shall be the
close of business 15 days prior to such Distribution payment date unless
otherwise provided in the Declaration. The Debenture Issuer has the right under
the Indenture to defer payments of interest by extending the interest payment
period from time to time on the Debentures for a period not exceeding 20
consecutive quarters (each an "Extension Period"), provided that no Extension
Period shall last beyond the date of maturity of the Debentures and, as a
consequence of such deferral, Distributions will also be deferred. Despite such
deferral, quarterly Distributions will continue to accrue with interest thereon
(to the extent permitted by applicable law) at the Coupon Rate compounded
quarterly during any such Extension Period. Prior to the termination of any such
Extension Period, the Debenture Issuer may further extend such Extension Period;
provided that such Extension Period together with all such previous and further
extensions thereof may not exceed 20 consecutive quarters or extend beyond the
date of maturity of the Debentures. Upon the termination of any Extension Period
and the payment of all amounts then due, the Debenture Issuer may commence a new
Extension Period, subject to the above requirements.

     The Common Securities shall be redeemable as provided in the Declaration.

     The Common Securities shall be convertible into shares of Common Stock,
through (i) the exchange of Common Securities for a portion of the Debentures
and (ii) the immediate conversion of such Debentures into Debenture Issuer
Common Stock, in the manner and according to the term set forth in the
Declaration.

                                     A2-4
<PAGE>
 
                              CONVERSION REQUEST 

To:  The First National Bank of Chicago, 
     as Institutional Trustee of McKesson Financing Trust 

     The undersigned owner of these Common Securities hereby irrevocably
exercises the option to convert these Common Securities, or the portion below
designated, into Common Stock of McKesson Corporation (the "Common Stock") in
accordance with the terms of the Amended and Restated Declaration of Trust (the
"Declaration"), dated as of February 20, 1997, by William A. Armstrong and Ivan
D. Meyerson, as Regular Trustees, First Chicago Delaware Inc., as Delaware
Trustee, The First National Bank of Chicago, as Institutional Trustee, McKesson
Corporation, as Sponsor, and by the Holders, from time to time, of individual
beneficial interests in the Trust to be issued pursuant to the Declaration.
Pursuant to the aforementioned exercise of the option to convert these Common
Securities, the undersigned hereby directs the Conversion Agent (as that term is
defined in the Declaration) to (i) exchange such Common Securities for a portion
of the Debentures (as that term is defined in the Declaration) held by the Trust
(at the rate of exchange specified in the terms of the Common Securities set
forth as Annex I to the Declaration) and (ii) immediately convert such
Debentures on behalf of the undersigned, into Common Stock (at the conversion
rate specified in the terms of the Common Securities set forth as Annex I to the
Declaration).

     The undersigned does also hereby direct the Conversion Agent that the
shares issuable and deliverable upon conversion, together with any check in
payment for fractional shares, be issued in the name of and delivered to the
undersigned, unless a different name has been indicated in the assignment below.
If shares are to be issued in the name of a person other than the undersigned,
the undersigned will pay all transfer taxes payable with respect thereto.

                                     A2-5
<PAGE>
 
Date:  _______________, ____

                              in whole _____      in part _____

                              Number of Convertible Preferred Securities to be
                              converted:  ____________________

                              If a name or names other than the undersigned,
                              please indicate in the spaces below the name or
                              names in which the shares of Common Stock are to
                              be issued, along with the address or addresses of
                              such person or persons


                              __________________________________________________
                              __________________________________________________
                              __________________________________________________
                              __________________________________________________
                              __________________________________________________
 

                              __________________________________________________
                              Signature (for conversion only)

                              Please Print or Typewrite Name and Address,
                              Including Zip Code, and Social Security or Other
                              Identifying Number

 
                              __________________________________________________
                              __________________________________________________
                              __________________________________________________


                              Signature Guarantee:/*/ __________________________


___________________

     /*/ (Signature must be guaranteed by an "eligible guarantor institution,"
that is, a bank, stockbroker, savings and loan association or credit union
meeting the requirements of the Conversion Agent, which requirements include
membership or participation in the Securities Transfer Agents Medallion Program
("STAMP") or such other "signature guarantee program" as may be determined by
the Conversion Agent in addition to, or in substitution for, STAMP, all in
accordance with the Securities Exchange Act of 1934, as amended.)

                                     A2-6
<PAGE>
 
                      [FORM OF ASSIGNMENT FOR SECURITY OR
                COMMON STOCK ISSUABLE UPON CONVERSION THEREOF]

For value received ______________________ hereby sell(s), assign(s) and
transfer(s) unto _______________________________________________________________
   (Please insert social security or other taxpayer identification number of
                                  assignee.)

the within security and hereby irrevocably constitutes and appoints ____________
attorney to transfer the said security on the books of the Company, with full
power of substitution in the premises.

In connection with any transfer of the within security occurring prior to the
Transfer Restriction Termination Date, the undersigned confirms that such
security is being transferred:

     [_]  To McKesson Corporation or a subsidiary thereof; or

     [_]  Pursuant to and in compliance with Rule 144A under the Securities Act
          of 1933, as amended; or

     [_]  To an Institutional Accredited Investor pursuant to and in compliance
          with the Securities Act of 1933, as amended; or

     [_]  Pursuant to and in compliance with Regulation S under the Securities
          Act of 1933, as amended; or

     [_]  Pursuant to and in compliance with Rule 144 under the Securities Act
          of 1933, as amended; or

     [_]  Pursuant to an effective registration statement.

                                     A2-7
<PAGE>
 
and unless the box below is checked, the undersigned confirms that such security
is not being transferred to an "affiliate" of the Company as defined in Rule 144
under the Securities Act of 1933, as amended (an "Affiliate"):

     [_]  The transferee is an Affiliate of the Company.


Dated: ____________________________
 
Signature(s)
                                        ______________________________________


                                        ______________________________________
 
 
                                        ______________________________________
                                        Signature Guarantee/*/


NOTICE:  The above signatures of the holder(s) hereof must correspond with the
name as written upon the face of this Security in every particular without
alteration or enlargement or any change whatever.


______________________

     /*/ (Signature must be guaranteed by an "eligible guarantor institution,"
that is, a bank, stockbroker, savings and loan association or credit union
meeting the requirements of the Conversion Agent, which requirements include
membership or participation in the Securities Transfer Agents Medallion Program
("STAMP") or such other "signature guarantee program" as may be determined by
the Conversion Agent in addition to, or in substitution for, STAMP, all in
accordance with the Securities Exchange Act of 1934, as amended.)

                                     A2-8
<PAGE>
 
                                   EXHIBIT B

                             SPECIMEN OF DEBENTURE

                                      B-1
<PAGE>
 
                                   EXHIBIT C

                              PLACEMENT AGREEMENT

                                      C-1

<PAGE>
 
                                                                     Exhibit 4.3
                                                                     -----------

________________________________________________________________________________



                             McKESSON CORPORATION

                                      and

                      The First National Bank of Chicago,
                                  as Trustee

                               _________________

                 5% CONVERTIBLE JUNIOR SUBORDINATED DEBENTURES

                               _________________

                                   INDENTURE



                         Dated as of February 20, 1997

________________________________________________________________________________
<PAGE>
 
                             McKESSON CORPORATION


          Reconciliation and tie between Trust Indenture Act of 1939
                     and Indenture dated as of May 1, 1996



<TABLE>
<CAPTION>
Trust Indenture
  Act Section                                            Indenture Section
- - -----------------                                        -----------------
<S>                                                      <C>
  310(a)(1)............................................        6.10
     (a)(2)............................................        6.10
     (a)(3)............................................        Not Applicable
     (a)(4)............................................        Not Applicable
     (a)(5)............................................        6.10
     (b)...............................................        6.8, 6.10
  311(a)...............................................        6.11
     (b)...............................................        6.11
  312(a)...............................................        4.1 and 4.2
     (b)...............................................        4.2
     (c)...............................................        4.2
  313(a)(1)-(5) & (7)(8)  .............................        6.6
     (a)(6)............................................        Not Applicable
     (b)(1)............................................        Not Applicable
     (b)(2)............................................        6.6
     (c)...............................................        6.6
     (d)...............................................        6.6
  314(a)(1)-(3)........................................        4.3
     (a)(4)............................................        3.4
     (b)...............................................        Not Applicable
     (c)(1)............................................        11.5
     (c)(2)............................................        11.5
     (c)(3)............................................        Not Applicable
     (d)...............................................        Not Applicable
     (e)...............................................        11.5
     (f)...............................................        Not Applicable
  315(a)...............................................        Not Applicable
     (b)...............................................        6.5
     (c)...............................................        6.1
     (d)...............................................        6.1
     (d)(1)............................................        6.1
     (d)(2)............................................        6.1
     (d)(3)............................................        6.1
     (e)...............................................        5.10
</TABLE>
<PAGE>
 
<TABLE>
     <S>                                                       <C>
     316(a)............................................        7.4
       (a)(1)(A).......................................        5.8
       (a)(1)(B).......................................        5.1, 5.9
       (a)(2)..........................................        Not Applicable
       (b).............................................        5.6
       (c).............................................        7.1
     317(a)(1).........................................        5.2
       (a)(2)..........................................        5.2
       (b).............................................        3.3
     318(a)............................................        11.7
</TABLE>

_______________________________

Note:  This reconciliation and tie shall not, for any purpose, be deemed to be
       part of the Indenture.
<PAGE>
 
                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                            Page
                                                                            ----

                                   ARTICLE I

                                  DEFINITIONS
<S>                                                                         <C>
Section 1.1    Certain Terms Defined.........................................  1


                                  ARTICLE II

                           THE CONVERTIBLE DEBENTURES

Section 2.1    Designation and Principal Amount.............................. 12
Section 2.2    Maturity...................................................... 12
Section 2.3    Form and Payment.............................................. 12
Section 2.4    Exchange and Registration of Transfer of Convertible
               Debentures; Restrictions on Transfers; Depositary............. 12
Section 2.5    Interest...................................................... 17
Section 2.6    Authentication and Delivery of Convertible Debentures......... 18
Section 2.7    Execution of Convertible Debentures........................... 19
Section 2.8    Certificate of Authentication................................. 19
Section 2.9    Denomination and Date of Convertible Debentures;
               Payments of Interest.......................................... 20
Section 2.10   Registration, Transfer and Exchange........................... 21
Section 2.11   Mutilated, Defaced, Destroyed, Lost and Stolen
               Convertible Debentures........................................ 24
Section 2.12   Cancellation of Convertible Debentures........................ 25
Section 2.13   Temporary Convertible Debentures.............................. 25

                                  ARTICLE III

                            COVENANTS OF THE COMPANY

Section 3.1    Payment of Principal and Interest............................. 26
Section 3.2    Offices for Payment, etc...................................... 26
Section 3.3    Paying Agents................................................. 27
Section 3.4    Written Statement to Trustee.................................. 27
Section 3.5    Limitation on Dividends; Transactions with Affiliates......... 28
Section 3.6    Covenants as to McKesson Trust................................ 28
Section 3.7    Existence..................................................... 28
</TABLE>

                                       i
<PAGE>
 
<TABLE>
<CAPTION>
                                   ARTICLE IV
             HOLDERS OF CONVERTIBLE DEBENTURES LISTS AND REPORTS
                        BY THE COMPANY AND THE TRUSTEE
<S>                                                                           <C>
Section 4.1    Company to Furnish Trustee Information as to Names
               and Addresses of Holders of Convertible Debentures............ 29
Section 4.2    Preservation and Disclosure of Holders of Convertible
               Debentures' Lists............................................. 29
Section 4.3    Reports by the Company........................................ 30

                                   ARTICLE V

                     REMEDIES OF THE TRUSTEE AND HOLDERS OF
                   CONVERTIBLE DEBENTURES ON EVENT OF DEFAULT

Section 5.1    Event of Default Defined; Acceleration of Maturity;
               Waiver of Default............................................. 31
Section 5.2    Collection of Indebtedness by Trustee; Trustee May
               Prove Debt.................................................... 33
Section 5.3    Application of Proceeds....................................... 35
Section 5.4    Restoration of Rights on Abandonment of Proceedings........... 36
Section 5.5    Limitations on Suits by Holders of Convertible
               Debentures.................................................... 36
Section 5.6    Unconditional Right of Holders of Convertible
               Debentures to Institute Certain Suits......................... 37
Section 5.7    Powers and Remedies Cumulative; Delay or Omission
               Not Waiver of Default......................................... 37
Section 5.8    Control by Holders of Convertible Debentures.................. 37
Section 5.9    Waiver of Past Defaults....................................... 38
Section 5.10   Right of Court to Require Filing of Undertaking to Pay
               Costs......................................................... 38
Section 5.11   Suits for Enforcement......................................... 39

                                   ARTICLE VI

                             CONCERNING THE TRUSTEE

Section 6.1    Duties of the Trustee......................................... 39
Section 6.2    Rights of Trustee............................................. 40
Section 6.3    Individual Rights of Trustee.................................. 41
Section 6.4    Trustee's Disclaimer.......................................... 41
</TABLE>

                                      ii
<PAGE>
 
<TABLE>
<S>                                                                           <C>
Section 6.5     Notice of Defaults........................................... 41
Section 6.6     Reports by Trustee to Holders................................ 41
Section 6.7     Compensation and Indemnity................................... 41
Section 6.8     Replacement of Trustee....................................... 42
Section 6.9     Successor Trustee by Merger.................................. 43
Section 6.10    Eligibility; Disqualification................................ 43
Section 6.11    Preferential Collection of Claims Against Company............ 43

                                  ARTICLE VII

                CONCERNING THE HOLDERS OF CONVERTIBLE DEBENTURES

Section 7.1    Evidence of Action Taken by Holders of Convertible
               Debentures.................................................... 43
Section 7.2    Proof of Execution of Instruments............................. 44
Section 7.3    Holders to be Treated as Owners............................... 44
Section 7.4    Convertible Debentures Owned by Company Deemed Not
               Outstanding................................................... 44
Section 7.5    Right of Revocation of Action Taken........................... 44

                                  ARTICLE VIII

                            SUPPLEMENTAL INDENTURES

Section 8.1    Supplemental Indentures Without Consent of Holders of
               Convertible Debentures........................................ 45
Section 8.2    Supplemental Indentures With Consent of Holders of
               Convertible Debentures........................................ 46
Section 8.3    Effect of Supplemental Indenture.............................. 47
Section 8.4    Documents to Be Given to Trustee.............................. 47
Section 8.5    Notation on Convertible Debentures in Respect of
               Supplemental Indentures....................................... 47

                                   ARTICLE IX

                   CONSOLIDATION, MERGER, SALE OR CONVEYANCE

Section 9.1    Company May Consolidate, etc., on Certain Terms............... 47
Section 9.2    Successor Corporation Substituted............................. 48
Section 9.3    Opinion of Counsel to Trustee................................. 48
</TABLE>

                                      iii
<PAGE>
 
<TABLE>
<CAPTION> 
                                   ARTICLE X

                   REDEMPTION OF THE CONVERTIBLE DEBENTURES

<S>                                                                           <C> 
Section 10.1   Tax Event Redemption.......................................... 49
Section 10.2   Optional Redemption by Company................................ 49
Section 10.3   No Sinking Fund............................................... 51
Section 10.4   Election to Redeem; Notice of Redemption; Partial
               Redemptions................................................... 51
Section 10.5   Payment of Convertible Debentures Called for
               Redemption.................................................... 52
Section 10.6   Exclusion of Certain Convertible Debentures from
               Eligibility for Selection for Redemption...................... 53

                                  ARTICLE XI

                     EXTENSION OF INTEREST PAYMENT PERIOD

Section 11.1   Extension of Interest Payment Period.......................... 53
Section 11.2   Notice of Extension........................................... 54

                                  ARTICLE XII

                      CONVERSION OF CONVERTIBLE DEBENTURES

Section 12.1   Conversion Rights............................................. 54
Section 12.2   Conversion Procedures......................................... 55
Section 12.3   Conversion Price Adjustments.................................. 56
Section 12.4   Merger, Consolidation or Sale of Assets....................... 62
Section 12.5   Notice of Adjustments of Conversion Price..................... 63
Section 12.6   Prior Notice of Certain Events................................ 64
Section 12.7   Certain Additional Rights..................................... 65
Section 12.8   Trustee Not Responsible for Determining Conversion
               Price or Adjustments.......................................... 65
Section 12.9   Reservation of Shares of Common Stock......................... 66
Section 12.10  Payment of Certain Taxes upon Conversion...................... 66
Section 12.11  Nonassessability.............................................. 66
</TABLE>

                                      iv
<PAGE>
 
<TABLE>
<CAPTION>
                                  ARTICLE XIII

                    SUBORDINATION OF CONVERTIBLE DEBENTURES

<S>                                                                           <C>
Section 13.1   Convertible Debentures Subordinate to Senior
               Indebtedness.................................................. 66
Section 13.2   Payment Over of Proceeds upon Dissolution, Etc................ 66
Section 13.3   Prior Payment to Senior Indebtedness upon Acceleration
               of Convertible Debentures..................................... 68
Section 13.4   No Payment When Senior Indebtedness in Default................ 68
Section 13.5   Payment Permitted in Certain Situations....................... 68
Section 13.6   Subrogation to Rights of Holders of Senior Indebtedness....... 69
Section 13.7   Provisions Solely to Define Relative Rights................... 69
Section 13.8   Trustee to Effectuate Subordination........................... 69
Section 13.9   No Waiver of Subordination Provisions......................... 69
Section 13.10  Notice to Trustee............................................. 70
Section 13.11  Reliance on Judicial Order or Certificate of Liquidating
               Agent......................................................... 71
Section 13.12  Trustee Not Fiduciary for Holders of Senior Indebtedness...... 71
Section 13.13  Rights of Trustee as Holder of Senior Indebtedness;
               Preservation of Trustee's Rights.............................. 71
Section 13.14  Article Applicable to Paying Agents........................... 71
Section 13.15  Certain Conversions Deemed Payment............................ 72

                                  ARTICLE XIV

                                    EXPENSES

Section 14.1   Payment of Expenses........................................... 72
Section 14.2   Payment Upon Resignation or Removal........................... 73

                                   ARTICLE XV

                            MISCELLANEOUS PROVISIONS

Section 15.1   Incorporators, Stockholders, Officers and Directors of
               Company Exempt from Individual Liability...................... 73
Section 15.2   Provisions of Indenture for the Sole Benefit of Parties
               and Holders of Convertible Debentures......................... 73
Section 15.3   Right to Assign; Successors and Assigns Bound by
               Indenture..................................................... 74
Section 15.4   Notices and Demands on Company, Trustee and Holders
               of Convertible Debentures..................................... 74
</TABLE>

                                       v
<PAGE>
 
<TABLE>
<S>                                                                           <C>
Section 15.5   Officers' Certificates and Opinions of Counsel;
               Statements to Be Contained Therein............................ 75
Section 15.6   Payments Due on Saturdays, Sundays and Holidays............... 76
Section 15.7   Conflict of Any Provision of Indenture with Trust
               Indenture Act................................................. 76
Section 15.8   New York Law to Govern........................................ 76
Section 15.9   Counterparts.................................................. 76
Section 15.10  Effect of Headings; Gender.................................... 76
</TABLE>

                                      vi
<PAGE>
 
     THIS INDENTURE, dated as of February 20, 1997 between McKESSON CORPORATION,
a Delaware corporation (the "Company") and The First National Bank of Chicago,
(the "Trustee"),

                             W I T N E S S E T H:
                             - - - - - - - - - - 

     WHEREAS, the Company desires and has requested the Trustee to join it in
the execution and delivery of this Indenture in order to establish and provide
for the issuance by the Company of Convertible Debentures designated as its 5%
Convertible Junior Subordinated Debentures (the "Convertible Debentures"), a
specimen copy of which is attached hereto as Exhibit A, on the terms set forth
herein;

     WHEREAS, McKesson Financing Trust, a Delaware statutory business trust
("McKesson Trust" or the "Trust"), has offered to Morgan Stanley & Co.
Incorporated (the "Initial Purchaser") in a private placement $200,000,000
aggregate liquidation amount of its 5% Trust Convertible Preferred Securities
(the "Convertible Preferred Securities"), representing undivided beneficial
interests in the assets of the Trust, and proposes to invest the proceeds from
such offering, together with the proceeds of the issuance and sale by the Trust
to the Company of $6,186,000 aggregate liquidation amount of its Common
Securities, in $206,186,000 aggregate principal amount of the Convertible
Debentures; and

     WHEREAS, all things necessary to make this Indenture a valid agreement of
the Company and the Trustee, in accordance with its terms, have been done.

     NOW, THEREFORE:

     There is hereby established the terms of the Convertible Debentures to be
issued under this Indenture, which shall be as set forth herein and in the form
of Convertible Debentures attached hereto as Exhibit A, and in consideration of
the premises and the purchase and acceptance of the Convertible Debentures by
the holders thereof, the Company mutually covenants and agrees with the Trustee,
for the equal and proportionate benefit of all holders of the Convertible
Debentures, as follows:



                                   ARTICLE I

                                  DEFINITIONS

     Section 1.1  Certain Terms Defined.  The following terms (except as other
expressly provided or unless the context otherwise clearly requires) for all
purposes of this Indenture and of any indenture supplemental hereto shall have
the respective meanings specified in this Section.  All other terms used in this
Indenture that are defined in the Trust Indenture Act of 1939, as amended (the
"Trust Indenture Act"), or the definitions of which in the Securities Act of
1933, as amended (the "Securities Act"), are referred to in the Trust Indenture
Act, including terms defined therein by reference to the Securities Act (except
as herein otherwise expressly provided or unless the context otherwise clearly
requires), shall have the meanings
<PAGE>
 
assigned to such terms in the Trust Indenture Act and in the Securities Act as
in force at the date of this Indenture.  All accounting terms used herein and
not expressly defined shall have the meanings assigned to such terms in
accordance with generally accepted accounting principles, and the term
"generally accepted accounting principles" means such accounting principles as
are generally accepted at the time of any computation.  The words "herein,"
"hereof" and "hereunder" and other words of similar import refer to this
Indenture as a whole, as supplemented and amended from time to time, and not to
any particular Article, Section or other subdivision.  The terms defined in this
Article have the meanings assigned to them in this Article and include the
plural as well as the singular.

     "Additional Sums" shall have the meaning set forth in Section 2.5(c).

     "Affiliate" has the same meaning as given to that term in Rule 405 of the
Securities Act of 1933, as amended, or any successor rule thereunder.

     "Applicable Price" means (i) in the event of a Non-Stock Fundamental Change
in which the holders of the Common Stock receive only cash, the amount of cash
received by a holder of one share of Common Stock and (ii) in the event of any
other Fundamental Change, the average of the daily Closing Price for one share
of Common Stock during the 10 Trading Days immediately prior to the record date
for the determination of the holders of Common Stock entitled to receive cash,
securities, property or other assets in connection with such Fundamental Change
or, if there is no such record date, prior to the date upon which the holders of
the Common Stock shall have the right to receive such cash, securities, property
or other assets.

     "Board of Directors" means either the Board of Directors of the Company or
any duly authorized committee of that Board.

     "Board Resolution" means a copy of a resolution certified by the Secretary
or an Assistant Secretary of the Company to have been duly adopted by the Board
of Directors and to be in full force and effect on the date of such
certification, and delivered to the Trustee.

     "Business Day" means any day other than a Saturday, Sunday, or any other
day on which banking institutions in New York, New York or Wilmington, Delaware
are permitted or required by any applicable law to close.

     "Capital Stock" means, with respect to any Person, any and all shares,
interests, units representing interests, participations, rights in or other
equivalents (however designated) of such Person's capital stock, including, with
respect to partnerships, partnership interests (whether general or limited) and
any other interest or participation that confers upon a Person the right to
receive a share of the profits and losses of, or distributions of assets of,
such partnership, and any rights (other than debt securities convertible into
capital stock), warrants or options exchangeable for or convertible into such
capital stock.

     "Certificated Convertible Preferred Securities" means Convertible Preferred
Securities issued in definitive registered form.

                                       2
<PAGE>
 
     "Clearing Agent" means an organization registered as a "Clearing Agency"
pursuant to Section 17A of the Exchange Act that is acting as a depositary for
the Convertible Debentures and in whose name or in the name of a nominee of that
organization shall be registered one or more Global Debentures and which shall
undertake to effect book entry transfers and pledges of the Convertible
Debentures.

     "Closing Price" with respect to any security on any day means the last
reported sale price, regular way on such day, or, if no sale takes place on such
day, the average of the reported closing bid and asked prices on such day,
regular way, in either case as reported on the NYSE Composite Tape, or, if such
security is not listed or admitted to trading on the New York Stock Exchange, on
the principal national securities exchange on which such security is listed or
admitted to trading, or, if such security is not listed or admitted to trading
on a national securities exchange, on the National Market System of the National
Association of Securities Dealers, Inc., or, if such security is not quoted or
admitted to trading on such quotation system, on the principal quotation system
on which such security is listed or admitted to trading or quoted, or, if not
listed or admitted to trading or quoted on any national securities exchange or
quotation system, the average of the closing bid and asked prices of such
security in the over-the-counter market on the day in question as reported by
the National Quotation Bureau Incorporated, or a similar generally accepted
reporting service, or, if not so available in such manner, as furnished by any
New York Stock Exchange member firm selected from time to time by the Board of
Directors (or any committee duly authorized by the Board of Directors) of the
Company for that purpose or, if not so available in such manner, as otherwise
determined in good faith by the Board of Directors (or any committee duly
authorized by the Board of Directors) of the Company.

     "Commission" means the Securities and Exchange Commission, as from time to
time constituted, created under the Exchange Act, as amended, or if at any time
after the execution and delivery of this Indenture such Commission is not
existing and performing the duties now assigned to it under the Trust Indenture
Act, then the body performing such duties on such date.

     "Common Securities" means undivided beneficial interests in the assets of
the McKesson Trust which rank pari passu with Convertible Preferred Securities
issued by the McKesson Trust; provided, however, that upon the occurrence of an
Event of Default, the rights of holders of Common Securities to payment in
respect to distributions and payments upon liquidation, redemption and otherwise
are subordinated to the rights of holders of Convertible Preferred Securities.

     "Common Securities Guarantee" means the Common Securities Guarantee
Agreement dated as of February 20, 1997 by the Guarantor.

     "Common Securities Registration Rights Agreement" means the Registration
Rights Agreement dated as of February 20, 1997 by the Company and the Trust,
relating to the Common Securities.

                                       3
<PAGE>
 
     "Common Stock" includes any stock of any class of the Company which has no
preference in respect of dividends or of amounts payable in the event of any
voluntary or involuntary liquidation, dissolution or winding-up of the Company
and which is not subject to redemption by the Company.

     "Common Stock Fundamental Change" means any Fundamental Change in which
more than 50% of the value (as determined in good faith by the Board of
Directors of the Company) of the consideration received by holders of Common
Stock consists of common stock that, for the 10 Trading Days immediately prior
to such Fundamental Change, has been admitted for listing or admitted for
listing subject to notice of issuance on a national securities exchange or
quoted on The Nasdaq National Market; provided, however, that a Fundamental
Change shall not be a Common Stock Fundamental Change unless either (i) the
Company continues to exist after the occurrence of such Fundamental Change and
the outstanding Convertible Preferred Securities continue to exist as
outstanding Convertible Preferred Securities, or (ii) not later than the
occurrence of such Fundamental Change, the outstanding Convertible Preferred
Securities are converted into or exchanged for convertible preferred stock or
debentures of a corporation succeeding to the business of the Company, which
convertible preferred stock has powers, preferences and relative, participating,
optional or other rights, and qualifications, limitations and restrictions
substantially similar to those of the Convertible Preferred Securities and which
debentures have terms substantially similar to those of the Convertible
Debentures.

     "Company" means McKesson Corporation, a Delaware corporation, until a
successor corporation shall have become such pursuant to the applicable
provisions of this Indenture, and thereafter "Company" shall mean such successor
corporation.

     "Compound Interest" shall have the meaning specified in Section 11.1.

     "Convertible Debenture" or "Convertible Debentures" has the meaning stated
in the first recital of this Indenture and more particularly means any
Convertible Debentures authenticated and delivered under this Indenture.

     "Convertible Preferred Securities" has the meaning specified in the
recitals to this Indenture.

     "Conversion Agent" has the meaning assigned thereto in the Declaration.

     "Conversion Price" has the meaning set forth in Section 12.1.

     "Corporate Trust Office" means the principal corporate trust office of the
Trustee at which at any particular time its corporate trust business shall be
administered, which office at the date of execution of this Indenture is located
at One First National Plaza, Suite 0126, Chicago, IL  60670-0126, Attention:
Corporation Trust Services Division.

                                       4
<PAGE>
 
     "Declaration" means the Amended and Restated Declaration of Trust of
McKesson Financing Trust, a Delaware statutory business trust, dated as of
February 20, 1997.

     "Debt" of a Person means, all indebtedness of such Person which is for
money borrowed.

     "defaulted interest" has the meaning specified in Section 2.9.

     "Deferred Interest" has the meaning specified in Section 11.1.

     "Delaware Trustee" has the meaning specified in the Declaration.

     "Depositary" means, with respect to the Convertible Debentures issuable or
issued in the form of one or more Global Debentures, the Person designated as
Depositary by the Company until a successor Depositary shall have become such
pursuant to the applicable provisions of this Indenture, and thereafter
"Depositary" shall mean or include each Person who is then a Depositary
hereunder, and if at any time there is more than one such person, "Depositary"
as used with respect to the Convertible Debentures shall mean the Depositary
with respect to the Global Debentures.

     "Depositary Convertible Debenture" means a Convertible Debenture executed
by the Company and authenticated and delivered by the Trustee to the Depositary
or pursuant to the Depositary's instruction, all in accordance with this
Indenture, which (i) shall be registered as to principal and interest in the
name of the Depositary or its nominee and (ii) shall represent, and shall be
denominated in an amount equal to the aggregate principal amount of, all or a
portion of the Outstanding Convertible Debentures.

     "Dissolution Event" means that, as a result of the occurrence and
continuation of a Special Event (as described in the Declaration), the Trust is
to be dissolved in accordance with the Declaration, and the Convertible
Debentures held by the Institutional Trustee are to be distributed to the
holders of the Trust Securities issued by the Trust pro rata in accordance with
the Declaration.

     "Dollar" means the coin or currency of the United States of America which
as of the time of payment is legal tender for the payment of public and private
debts.

     "Event of Default" has the meaning specified in Section 5.1.

     "Exchange Act" means the Securities Exchange Act of 1934, as amended.

     "Extension Period" has the meaning specified in Section 11.1.

     "Fundamental Change" means the occurrence of any transaction or event or
series of transactions or events pursuant to which all or substantially all of
the Common Stock shall be exchanged for, converted into, acquired for or shall
constitute solely the right to receive 

                                       5
<PAGE>
 
cash, securities, property or other assets (whether by means of an exchange
offer, liquidation, tender offer, consolidation, merger, combination,
reclassification, recapitalization or otherwise); provided, however, in the case
of any such series of transactions or events, for purposes of adjustment of the
Conversion Price, such Fundamental Change shall be deemed to have occurred when
substantially all of the Common Stock shall have been exchanged for, converted
into or acquired for, or shall constitute solely the right to receive, such
cash, securities, property or other assets, but the adjustment shall be based
upon the consideration that the holders of Common Stock received in the
transaction or event as a result of which more than 50% of the Common Stock
shall have been exchanged for, converted into or acquired for, or shall
constitute solely the right to receive, such cash, securities, property or other
assets.

     "Global Debenture" has the meaning specified in Section 2.4(a).

     "Government Obligations" means securities which are (i) direct obligations
of the United States government for which its full faith and credit is pledged
or (ii) obligations of a Person controlled or supervised by, or acting as an
agency or instrumentality of, the United States government, the payment of which
obligations is unconditionally guaranteed by the United States government, and
which, in either case, are full faith and credit obligations of the United
States government, and which are not callable or redeemable at the option of the
issuer thereof prior to their stated maturity.

     "Guarantor" means the Company in its capacity as guarantor under any Trust
Securities Guarantees.

     "Holder" or "Holder of Convertible Debentures" or other similar terms mean
the person in whose name such Convertible Debenture is registered in the
Security Register.

     "incur" means to issue, incur, assume, guarantee, become liable,
contingently or otherwise, with respect to, or otherwise become responsible for
the payment of, any Debt.

     "Indenture" means this instrument as originally executed and delivered or
as it may from time to time be amended or supplemented as herein provided, as so
amended or supplemented or both, and shall include the forms and terms of the
Convertible Debentures appearing as Exhibit A to this instrument.

     "Institutional Trustee" has the meaning specified in the Declaration.

     "Interest Payment Date," when used with respect to any Convertible
Debenture, means the Stated Maturity of an installment of interest on such
Convertible Debenture.

     "Lien" means any mortgage or deed of trust, pledge, assignment, security
interest, lien, charge, or other encumbrance or preferential arrangement
(including, without limitation, any conditional sale or other title retention
agreement having substantially the same economic effect as any of the
foregoing).

                                       6
<PAGE>
 
     "Maturity" when used with respect to any Convertible Debenture means the
date on which the principal of such Convertible Debenture or an installment of
principal becomes due and payable as therein or herein provided, whether at
Stated Maturity or by declaration of acceleration, call for redemption or
otherwise.

     "Maturity Date" means the date on which the Convertible Debentures mature
and on which the principal shall be due and payable together with all accrued
and unpaid interest thereon including Additional Sums, if any, and (to the
extent permitted by applicable law) Compound Interest, if any.

     "Non-Stock Fundamental Change" means any Fundamental Change other than a
Common Stock Fundamental Change.

     "Non-U.S. Person" means any person that is not a "U.S. person" as such term
is defined in Rule 902 under the Securities Act.

     "Officers' Certificate" means a certificate signed on behalf of the Company
by the Chairman of the Board of Directors or the vice chairman or the president
or any vice president and by the treasurer, the controller, any assistant
treasurer, the secretary or any assistant secretary of the Company and delivered
to the Trustee.  Each such certificate shall include the statements provided for
in Section 15.5.

     "Opinion of Counsel" means a written opinion of legal counsel, who may be
an employee of or counsel to the Company, and who shall be reasonably acceptable
to the Trustee.  Each Opinion of Counsel shall include the statements provided
for in Section 15.5, if and to the extent required hereby.

     "Optional Redemption Price" has the meaning specified in Section 10.2.

     "Outstanding" when used with reference to Convertible Debentures, subject
to the provisions of Section 7.4, means, as of any particular time, all
Convertible Debentures authenticated and delivered under this Indenture, except

          (a) Convertible Debentures theretofore cancelled by the Trustee or
     delivered to the Trustee for cancellation;

          (b) Convertible Debentures, or portions thereof, for the payment or
     redemption of which moneys in the necessary amount and in the required
     currency shall have been deposited in trust with the Trustee or with any
     Paying Agent (other than the Company) or shall have been set aside,
     segregated and held in trust by the Company for the Holders of such
     Convertible Debentures (if the Company shall act as its own Paying Agent),
     provided that if such Convertible Debentures, or portions thereof, are to
     be redeemed prior to the Maturity thereof, notice of such redemption shall
     have been given as herein provided, or provision satisfactory to the
     Trustee shall have been made for giving such notice; and

                                       7
<PAGE>
 
          (c) Convertible Debentures that have been paid pursuant to Section
     2.11, converted into Common Stock pursuant to Article XII, or in exchange
     for or in lieu of which other Convertible Debentures have been
     authenticated and delivered pursuant to the Indenture (except with respect
     to any such Convertible Debenture as to which proof satisfactory to the
     Trustee and the Company is presented that such Convertible Debenture is
     held by a person in whose hands such Convertible Debenture is a legal,
     valid and binding obligation of the Company).

     "Paying Agent" means any Person (which may include the Company) authorized
by the Company to pay the principal of or interest, if any, on any Convertible
Debenture on behalf of the Company.

     "Persons" or "Person" means any individual, corporation, partnership, joint
venture, limited liability company, association, joint stock company, trust,
unincorporated organization or government or any agency or political subdivision
thereof.

     "Place of Payment", when used with respect to the Convertible Debentures,
means the place or places where the principal of and interest, if any, on the
Convertible Debentures are payable as specified pursuant to Section 3.2.

     "Placement Agreement" means the Placement Agreement dated February 13, 1997
between the Company and the Trust and Morgan Stanley & Co. Incorporated.

     "Predecessor Convertible Debenture" of a Convertible Debenture means every
previous Convertible Debenture evidencing all or a portion of the same debt as
that evidenced by such Convertible Debenture; and, for the purposes of this
definition, a Convertible Debenture authenticated and delivered under Section
2.11 in exchange for or in lieu of a mutilated, destroyed, lost or stolen
Convertible Debenture shall be deemed to evidence the same debt as the
mutilated, destroyed, lost or stolen Convertible Debenture.

     "Preferred Securities Guarantee" means the Preferred Securities Guarantee
Agreement dated as of February 20, 1997 between the Guarantor and The First
National Bank of Chicago, as Preferred Guarantee Trustee.

     "Preferred Securities Registration Rights Agreement" means the Registration
Rights Agreement dated as of February 20, 1997 among the Company, the Trust and
Morgan Stanley & Co. Incorporated as the Initial Purchaser, relating to the
Convertible Preferred Securities.

     "Preferred Stock", as applied to the Capital Stock of any Person, means
Capital Stock of such Person of any class or classes (however designated) that
ranks prior, as to the payment of dividends or as to the distribution of assets
upon any voluntary or involuntary liquidation, dissolution or winding up of such
Person, to shares of Capital Stock of any other class of such Person.

                                       8
<PAGE>
 
     "principal" whenever used with reference to the Convertible Debentures or
any Convertible Debenture or any portion thereof, shall be deemed to include
"and premium, if any."

     "Purchaser Stock Price" means, with respect to any Common Stock Fundamental
Change, the average of the daily Closing Price for one share of the common stock
received by holders of Common Stock (determined as provided herein) in such
Common Stock Fundamental Change during the 10 Trading Days immediately prior to
the date fixed for the determination of the holders of Common Stock entitled to
receive such common stock or, if there is no such date, prior to the date upon
which the holders of Common Stock shall have the right to receive such common
stock.

     "QIB" or "Qualified Institutional Buyer" shall mean "Qualified
Institutional Buyer" as such term is defined in Rule 144A under the Securities
Act.

     "record date" has the meaning specified in Section 2.9.

     "Reference Market Price" initially means $39.75 (which is an amount equal
to 66-2/3% of the reported last sale price for the Common Stock on the New York
Stock Exchange on February 13, 1997) and, in the event of any adjustment to the
Conversion Price other than as a result of a Fundamental Change, the Reference
Market Price shall also be adjusted so that the ratio of the Reference Market
Price to the Conversion Price after giving effect to any such adjustment shall
also be the same as the ratio of the initial Reference Market Price to the
initial Conversion Price.

     "Registrar" has the meaning specified in Section 2.10.

     "Registration Rights Agreements" means the Preferred Securities
Registration Rights Agreement and the Common Securities Registration Rights
Agreement.

     "Regulation S" means Regulation S under the Securities Act.

     "Representative" means the (a) indenture trustee or other trustee, agent or
representative for any Senior Indebtedness or (b) with respect to any Senior
Indebtedness that does not have any such trustee, agent or other representative
(i) in the case of such Senior Indebtedness issued pursuant to an agreement
providing for voting arrangements as among the holders or owners of such Senior
Indebtedness, any holder or owner of such Senior Indebtedness acting with the
consent of the required persons necessary to bind such holders or owners of such
Senior Indebtedness and (ii) in the case of all other such Senior Indebtedness,
the holder or owner of such Senior Indebtedness.

     "Responsible Officer" when used with respect to the Trustee means any
officer within the corporate trust department (or any successor department) of
the Trustee including any vice president, assistant vice president, assistant
secretary, senior trust officer, trust officer or any other officer or assistant
officer of the Trustee customarily performing functions 

                                       9
<PAGE>
 
similar to those performed by the persons who at the time shall be such
officers, respectively, or to whom any corporate trust matter is referred at the
Corporate Trust Office because of his or her knowledge of and familiarity with
the particular subject.

     "Rule 144" means Rule 144 under the Securities Act.

     "Rule 144A" means Rule 144A under the Securities Act.

     "Securities Act" means the Securities Act of 1933, as amended.

     "Security Register" has the meaning specified in Section 2.10.

     "Senior Indebtedness" means, with respect to the Company, (i) the
principal, premium, if any, and interest in respect of (a) indebtedness of the
Company for money borrowed (but excluding trade accounts payable arising in the
ordinary course of business) under any credit agreements, notes, guarantees or
similar documents and (b) indebtedness evidenced by securities, debentures,
bonds or other similar instruments issued by the Company; (ii) all capital lease
obligations of the Company; (iii) all obligations of the Company issued or
assumed as the deferred purchase price of property, all conditional sale
obligations of the Company and all obligations of the Company under any title
retention agreement (but excluding trade accounts payable arising in the
ordinary course of business); (iv) all obligations of the Company for the
reimbursement on any letter of credit, banker's acceptance, security purchase
facility or similar credit transaction; (v) all obligations of the Company
(contingent or otherwise) with respect to an interest rate or other swap, cap or
collar agreements or other similar instruments or agreements or foreign
currency hedge, exchange, purchase or similar instruments or agreements; (vi)
all obligations of the types referred to in clauses (i) through (v) of other
Persons for the payment of which the Company is responsible or liable as
obligor, guarantor or otherwise; and (vii) all obligations of the types referred
to in clauses (i) through (vi) above of other Persons secured by any lien on any
property or asset of the Company (whether or not such obligation is assumed by
the Company), whether outstand ing on the date of this Indenture or thereafter
created, incurred, assumed, guaranteed or in effect guaranteed by the Company,
except for any such indebtedness that is by its terms subordinated to or pari
passu with the Convertible Debentures.  Such Senior Indebtedness shall continue
to be Senior Indebtedness irrespective of any deferrals, renewals, extensions or
refundings of, or amendments, modifications, supplements or waivers of any term
of such Senior Indebtedness.

     "Stated Maturity" when used with respect to any Convertible Debenture or
any installment of principal thereof or interest thereon, means the date on
which the principal of such Convertible Debenture or such installment of
principal or interest is due and payable in accordance with the terms thereof.

     "Subsidiary" means any corporation, association, partnership or other
business entity of which more than 50% of the total voting power of the
outstanding Capital Stock (or other interests entitled (without regard to the
occurrence of any contingency) to vote in the election of directors, general
partners, managers, managing members, managing partners or trustees

                                       10
<PAGE>
 
thereof or, if such persons are not elected, to vote on any matter that is
submitted to the vote of all persons holding ownership interests in such entity)
is at the time owned or controlled, directly or indirectly, by (i) the Company,
(ii) the Company and one or more Subsidiaries or (iii) one or more Subsidiaries.

     "Trading Day" shall mean a day on which any securities are traded on the
national securities exchange or quotation system used to determine the Closing
Price or any day on which the New York Stock Exchange is open for trading.

     "Transfer Restriction Termination Date" means the earlier of the first date
on which (i) the Convertible Preferred Securities, the Convertible Debentures
and any Common Stock issued or issuable upon the conversion or exchange thereof
(other than (A) such securities acquired by the Company or any Affiliate thereof
since the Issue Date of the Convertible Preferred Securities and (B) Common
Stock issued upon the conversion or exchange of any such security described in
clause (A) above) may be sold pursuant to Rule 144(k) (or any successor
provision) and (ii) all the Offered Securities have been sold pursuant to an
effective registration statement.

     "Trust" or "McKesson Trust" means McKesson Financing Trust, a Delaware
statutory business trust.

     "Trust Indenture Act" or "TIA" (except as otherwise provided in Sections
8.1 and 8.2) means the Trust Indenture Act of 1939, as amended, as in force at
the date as of which this Indenture was originally executed.

     "Trust Securities" means the Common Securities and the Convertible
Preferred Securities of McKesson Trust.

     "Trust Securities Guarantees" means the Common Securities Guarantee and the
Preferred Securities Guarantee.

     "Trustee" means the Person identified as "Trustee" in the first paragraph
hereof until a successor Trustee shall have become such pursuant to the
provisions hereof, and thereafter, "Trustee" shall mean or include each Person
who is then a Trustee hereunder.

     "United States of America" or "United States" means the United States of
America (including the states and the District of Columbia), its territories,
possessions, the Commonwealth of Puerto Rico and other areas subject to its
jurisdiction.

     "U.S. Person" means (i) a citizen or resident of the United States, (ii) a
corporation, partnership or other entity created or organized in or under the
laws of the United States or any state or political subdivision thereof, (iii)
an estate the income of which is subject to United States federal income
taxation regardless of its sources or (iv) a trust whose administration is
subject to the primary supervision of a United States court and which has

                                       11
<PAGE>
 
one or more United States fiduciaries who have the authority to control all
substantial decisions of the Trust.

     "vice president" when used with respect to the Company or the Trustee,
means any vice president, whether or not designated by a number or a word or
words added before or after the title of "vice president."


                                  ARTICLE II

                          THE CONVERTIBLE DEBENTURES

     Section 2.1  Designation and Principal Amount.  There are hereby authorized
Debentures designated the "5% Junior Convertible Subordinated Debentures,"
limited in aggregate principal amount to $206,186,000 which amount shall be as
set forth in any written order of the Company for the authentication and
delivery of Convertible Debentures pursuant to Section 2.6 of this Indenture.

     Section 2.2  Maturity.  The Maturity Date is June 1, 2027.

     Section 2.3  Form and Payment.

     (a) Except as provided in Section 2.6, the Convertible Debentures shall be
issued in fully registered certificated form without coupons in denominations of
$50 in principal amount and integral multiples thereof.  Principal and interest
on the Convertible Debentures issued in certificated form will be payable, the
transfer of such Convertible Debentures will be registrable and such Convertible
Debentures will be exchangeable for Convertible Debentures bearing identical
terms and provisions at the office or agency of the Trustee; provided, however,
that payment of interest may be made at the option of the Company by check
mailed to the Holder at such address as shall appear in the Security Register.
Notwithstanding the foregoing, so long as the Holder of any Convertible
Debentures is the Institutional Trustee, the payment of the principal of and
interest (including Compound Interest and Additional Sums, if any) on such
Convertible Debentures held by the Institutional Trustee will be made at such
place and to such account as may be designated by the Institutional Trustee.

     (b) The Convertible Debentures are subject to the terms set forth in this
Indenture including, without limitation, Exhibit A hereto, the terms of which
                                         ---------                           
are hereby incorporated in their entirety by reference.

     (c) The Convertible Debentures and the Trustee's Certificate of
Authentication to be endorsed thereon are to be substantially in the form of
Exhibit A to this Indenture.
- - ---------                   

                                       12
<PAGE>
 
     Section 2.4  Exchange and Registration of Transfer of Convertible
Debentures; Restrictions on Transfers; Depositary.

     If distributed to holders of Trust Securities, the Convertible Debentures
will be issued to such holders in the same form as the Trust Securities that
such Convertible Debentures replace in accordance with the following procedures:

     (a) So long as Convertible Debentures are eligible for book-entry
settlement with the Depositary, or unless otherwise required by law, all
Convertible Debentures that are so eligible may be represented by one or more
Convertible Debentures in global form registered in the name of the Depositary
or the nominee of the Depositary, except as otherwise specified below.  The
transfer and exchange of beneficial interests in any such Convertible Debenture
in global form shall be effected through the Depositary in accordance with this
Indenture and the procedures of the Depositary therefor.

     Convertible Debentures that are distributed to QIBs in replacement of
Convertible Preferred Securities represented by a global Convertible Preferred
Security will be represented by a global Convertible Debenture (the "144A Global
Debenture").  Convertible Debentures that are distributed to Non-U.S. Persons in
replacement of Convertible Preferred Securities represented by a global
Convertible Preferred Security will be represented by a global Convertible
Debenture (the "Regulation S Global Debenture").  Each of the 144A Global
Debenture and the Regulation S Global Debenture shall be referred to herein as a
Global Debenture.  Convertible Debentures that are distributed to QIBs or to
Non-U.S. Persons in replacement of Certificated Convertible Preferred Securities
will be represented by definitive Convertible Debentures as set forth in Section
2.4(b). If Global Debentures are issued, transfers of interests in the
Convertible Debentures between the 144A Global Debenture and the Regulation S
Global Debenture will be made in accordance with the standing instructions and
procedures of the Depositary and its participants and the Trustee shall make
appropriate endorsements to reflect increases or decreases in the principal
amounts of such Global Debentures to reflect any such transfers.

     Except as provided below, beneficial owners of a Convertible Debenture in
global form shall not be entitled to have certificates registered in their
names, will not receive or be entitled to receive physical delivery of
certificates in definitive form and will not be considered Holders of such
Convertible Debentures in global form.

     (b) Convertible Preferred Securities held in certificated form, except for
certificates representing Convertible Preferred Securities held by the
Depositary or its nominee (or any successor Clearing Agency or its nominee),
shall upon presentation to the Trustee by the Institutional Trustee or by the
holder thereof or by the Institutional Trustee on behalf of such holder shall be
exchanged for Convertible Debentures in fully registered certificated form of
like aggregate principal amount and tenor.

     (c) So long as the Convertible Debentures are eligible for book-entry
settlement, and to the extent that Convertible Debentures are held by QIBs or
Non-U.S. Persons, as the case may be, in a Global Debenture, or unless otherwise
required by law, upon any transfer 

                                       13
<PAGE>
 
of a definitive Convertible Debenture to a QIB in accordance with Rule 144A or
to a Non-U.S. Person in accordance with Regulation S, unless otherwise requested
by the transferor, and upon receipt of the definitive Convertible Debenture or
Convertible Debentures being so transferred, together with a certification from
the transferor that the transfer is being made in compliance with Rule 144A or
Regulation S, as the case may be (or other evidence satisfactory to the
Trustee), the Trustee shall make an endorsement on any 144A Global Debenture or
any Regulation S Global Debenture, as the case may be, to reflect an increase in
the aggregate principal amount of the Convertible Debentures represented by such
Global Debenture, and the Trustee shall cancel such definitive Convertible
Debenture or Convertible Debentures in accordance with the standing instructions
and procedures of the Depositary, the aggregate principal amount of Convertible
Debentures represented by such Global Debenture to be increased accordingly;
provided that no definitive Convertible Debenture, or portion thereof, in
respect of which the Company or an Affiliate of the Company held any beneficial
interest shall be included in such Global Debenture until such definitive
Convertible Debenture is freely tradable in accordance with Rule 144(k);
provided further that the Trustee shall, at the written request of the Company,
issue Convertible Debentures in definitive form upon any transfer of a
beneficial interest in the Global Debenture to the Company or any Affiliate of
the Company.

     Any Global Debenture may be endorsed with or have incorporated in the text
thereof such legends or recitals or changes not inconsistent with the provisions
of this Indenture as may be required by the Depositary, by the New York Stock
Exchange or by the National Association of Securities Dealers, Inc. in order for
the Convertible Debentures to be tradeable on the PORTAL Market or as may be
required for the Convertible Debentures to be tradeable on any other market
developed for trading of securities pursuant to Rule 144A or required to comply
with any applicable law or any regulation thereunder or with the rules and
regulations of any securities exchange upon which the Convertible Debentures may
be listed or traded or to conform with any usage with respect thereto, or to
indicate any special limitations or restrictions to which any particular
Convertible Debentures are subject.

     (d) Each Convertible Debenture that bears or is required to bear the legend
set forth in this Section 2.4(d) (a "Restricted Convertible Debenture") shall be
subject to the restrictions on transfer provided in the legend set forth in this
Section 2.4(d), unless such restrictions on transfer shall be waived by the
written consent of the Company, and the Holder of each Restricted Convertible
Debenture, by such Holder's acceptance thereof, agrees to be bound by such
restrictions on transfer.  As used in this Section 2.4(d) and in Section 2.4(e),
the term "transfer" encompasses any sale, pledge, transfer or other disposition
of any Restricted Convertible Debenture.

     Prior to the Transfer Restriction Termination Date, any certificate
evidencing a Convertible Debenture shall bear a legend in substantially the
following form, unless otherwise agreed by the Company (with written notice
thereof to the Trustee):

     THE SECURITY EVIDENCED HEREBY HAS NOT BEEN REGISTERED UNDER THE U.S.
     SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND,
     ACCORDINGLY, MAY NOT BE OFFERED OR SOLD WITHIN

                                       14
<PAGE>
 
     THE UNITED STATES OR TO, OR FOR THE ACCOUNT OR BENEFIT OF, U.S. PERSONS
     EXCEPT AS SET FORTH IN THE FOLLOWING SENTENCE.  BY ITS ACQUISITION HEREOF,
     THE HOLDER (1) REPRESENTS THAT (A) IT IS A "QUALIFIED INSTITUTIONAL BUYER"
     (AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT) OR (B) IT IS AN
     INSTITUTIONAL "ACCREDITED INVESTOR" (AS DEFINED IN RULE 501(A)(1), (2), (3)
     OR (7) UNDER THE SECURITIES ACT) ("INSTITUTIONAL ACCREDITED INVESTOR") OR
     (C) IT IS NOT A U.S. PERSON AND IS ACQUIRING THE SECURITY EVIDENCED HEREBY
     IN AN OFFSHORE TRANSACTION, (2) AGREES THAT IT WILL NOT PRIOR TO THE
     EXPIRATION OF THE HOLDING PERIOD APPLICABLE TO SALES OF THE SECURITY
     EVIDENCED HEREBY UNDER RULE 144(K) UNDER THE SECURITIES ACT (OR ANY
     SUCCESSOR PROVISION) RESELL OR OTHERWISE TRANSFER THE SECURITY EVIDENCED
     HEREBY OR, IF THIS SECURITY IS CONVERTIBLE INTO COMMON STOCK, THE COMMON
     STOCK ISSUABLE UPON CONVERSION OR EXCHANGE OF THIS SECURITY EXCEPT (A) TO
     McKESSON CORPORATION (THE "COMPANY") OR ANY SUBSIDIARY THEREOF, (B)
     PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT,
     (C) TO A QUALIFIED INSTITUTIONAL BUYER IN COMPLIANCE WITH RULE 144A UNDER
     THE SECURITIES ACT, (D) TO AN INSTITUTIONAL ACCREDITED INVESTOR THAT, PRIOR
     TO SUCH TRANSFER, FURNISHES TO THE TRUSTEE FOR THE CONVERTIBLE PREFERRED
     SECURITIES OR THE CONVERTIBLE DEBENTURES, AS THE CASE MAY BE (OR, IF THIS
     CERTIFICATE EVIDENCES COMMON STOCK, THE TRANSFER AGENT FOR THE COMMON
     STOCK), A SIGNED LETTER CONTAINING CERTAIN REPRESENTATIONS AND AGREEMENTS
     RELATING TO THE RESTRICTIONS ON TRANSFER OF THE SECURITY EVIDENCED HEREBY
     (THE FORM OF WHICH LETTER CAN BE OBTAINED FROM SUCH TRUSTEE OR TRANSFER
     AGENT), (E) OUTSIDE THE UNITED STATES IN COMPLIANCE WITH RULE 904 UNDER THE
     SECURITIES ACT OR (F) PURSUANT TO THE EXEMPTION FROM REGISTRATION PROVIDED
     BY RULE 144 UNDER THE SECURITIES ACT (IF AVAILABLE), AND (3) AGREES THAT IT
     WILL DELIVER TO EACH PERSON TO WHOM THE SECURITY EVIDENCED HEREBY IS
     TRANSFERRED A NOTICE SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND.  IN
     CONNECTION WITH ANY TRANSFER OF THE SECURITY EVIDENCED HEREBY PRIOR TO THE
     EXPIRATION OF THE HOLDING PERIOD APPLICABLE TO SALES OF THE SECURITY
     EVIDENCED HEREBY UNDER RULE 144(K) UNDER THE SECURITIES ACT (OR ANY
     SUCCESSOR PROVISION), THE HOLDER MUST CHECK THE APPROPRIATE BOX SET FORTH
     ON THE REVERSE HEREOF RELATING TO THE MANNER OF SUCH TRANSFER AND SUBMIT
     THIS CERTIFICATE TO THE TRUSTEE FOR THE CONVERTIBLE PREFERRED SECURITIES OR
     THE CONVERTIBLE DEBENTURES, AS THE CASE MAY BE (OR, IF THIS CERTIFICATE
     EVIDENCES COMMON STOCK, SUCH HOLDER MUST FURNISH TO THE TRANSFER AGENT SUCH
     CERTIFICATIONS, LEGAL OPINIONS OR OTHER INFORMATION AS THE COMPANY OR
     McKESSON 

                                       15
<PAGE>
 
     FINANCING TRUST (THE "TRUST") MAY REASONABLY REQUIRE TO CONFIRM THAT SUCH
     TRANSFER IS BEING MADE PURSUANT TO AN EXEMPTION FROM, OR IN A TRANSACTION
     NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT). IF
     THIS CERTIFICATE DOES NOT EVIDENCE COMMON STOCK AND IF THE PROPOSED
     TRANSFEREE IS AN INSTITUTIONAL ACCREDITED INVESTOR OR A PURCHASER WHO IS
     NOT A U.S. PERSON, THE HOLDER MUST, PRIOR TO SUCH TRANSFER, FURNISH TO THE
     TRUSTEE FOR THE CONVERTIBLE PREFERRED SECURITIES OR THE CONVERTIBLE
     DEBENTURES, AS THE CASE MAY BE, SUCH CERTIFICATIONS, LEGAL OPINIONS OR
     OTHER INFORMATION AS THE COMPANY OR THE TRUST MAY REASONABLY REQUIRE TO
     CONFIRM THAT SUCH TRANSFER IS BEING MADE PURSUANT TO AN EXEMPTION FROM, OR
     IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE
     SECURITIES ACT. THIS LEGEND WILL BE REMOVED AFTER THE EXPIRATION OF THE
     HOLDING PERIOD APPLICABLE TO SALES OF THE SECURITY EVIDENCED HEREBY UNDER
     RULE 144(K) UNDER THE SECURITIES ACT. AS USED HEREIN, THE TERMS "OFFSHORE
     TRANSACTION," "UNITED STATES" AND "U.S. PERSON" HAVE THE MEANINGS GIVEN TO
     THEM BY REGULATION S UNDER THE SECURITIES ACT.

     Following the Transfer Restriction Termination Date, any Convertible
Debenture or security issued in exchange or substitution therefor (other than
(i) Convertible Debentures acquired by the Company or any Affiliate thereof
since the issue date of the Convertible Preferred Securities and (ii) Common
Stock issued upon the conversion or exchange of any Convertible Debenture
described in clause (i) above) may upon surrender of such Convertible Debenture
for exchange to the Registrar in accordance with the provisions of this Section
2.4, be exchanged for a new Convertible Debenture or Convertible Debentures, of
like tenor and aggregate principal amount, which shall not bear the restrictive
legend required by this Section 2.4(d).

     Notwithstanding any other provisions of this Indenture (other than the
provisions set forth in this Section 2.4(d)), a Global Debenture may not be
transferred as a whole except by the Depositary to a nominee of the Depositary
or by a nominee of the Depositary to the Depositary or another nominee to a
successor Depositary or a nominee of such successor Depositary.

     The Depositary shall be a clearing agency registered under the Exchange
Act.  The Company initially appoints The Depository Trust Company to act as
Depositary with respect to all or a portion of the Convertible Debentures in
global form.  Initially, the Global Debentures shall be issued to the
Depositary, registered in the name of Cede & Co., as the nominee of the
Depositary, and deposited with the Trustee as custodian for Cede & Co.

     Definitive Convertible Debentures issued in exchange for all or a part of a
Global Debenture pursuant to this Section 2.4(d) shall be registered in such
names and in such authorized denominations as the Depositary, pursuant to
instructions from its direct or 

                                       16
<PAGE>
 
indirect participants or otherwise, shall instruct the Trustee. Upon execution
and authentication, the Trustee shall deliver such definitive Convertible
Debentures to the person in whose names such definitive Convertible Debentures
are so registered.

     At such time as all interests in a Global Debenture have been redeemed,
converted, exchanged, repurchased or canceled, such Global Debenture shall be,
upon receipt thereof, canceled by the Trustee in accordance with standing
procedures and instructions of the Depositary.  At any time prior to such
cancellation, if any interest in a Global Debenture is exchanged for definitive
Convertible Debentures, redeemed, converted, exchanged or repurchased by the
Company pursuant to Article X or canceled, or transferred for part of a Global
Debenture, the principal amount of such Global Debenture shall, in accordance
with the standing procedures and instructions of the Depositary be reduced or
increased, as the case may be, and an endorsement shall be made on such Global
Debenture by, or at the direction of, the Trustee to reflect such reduction or
increase.

     (e) Any Convertible Debenture or Common Stock issued upon the conversion or
exchange of a Convertible Debenture that, prior to the Transfer Restriction
Termination Date, is purchased or owned by the Company or any Affiliate thereof
may not be resold by the Company or such Affiliate unless registered under the
Securities Act or resold pursuant to an exemption from the registration
requirements of the Securities Act in a transaction which results in such
Convertible Debentures or Common Stock, as the case may be, no longer being
"restricted securities" (as defined under Rule 144).

     Section 2.5  Interest.

     (a) Each Convertible Debenture will bear interest at the rate of 5% per
annum (the "Coupon Rate") from February 20, 1997 until the principal thereof
becomes due and payable, and on any overdue principal and (to the extent that
payment of such interest is enforceable under applicable law) on any overdue
installment of interest at the Coupon Rate, compounded quarterly, payable
(subject to the provisions of Article XI) quarterly in arrears on March 1, June
1, September 1 and December 1 of each year (each, an "Interest Payment Date"),
commencing on June 1, 1997, to the Person in whose name such Convertible
Debenture or any Predecessor Convertible Debenture is registered, at the close
of business on the record date for such interest installment, which shall be the
close of business on the fifteenth day prior to that Interest Payment Date.

     (b) The amount of interest payable for any period will be computed on the
basis of a 360-day year of twelve 30-day months.  The amount of interest payable
for any period shorter than a full quarterly period for which interest is
computed, will be computed on the basis of the actual number of days elapsed per
30-day month.  In the event that any date on which interest is payable on the
Convertible Debentures is not a Business Day, then payment of interest payable
on such date will be made on the next succeeding day that is a Business Day (and
without any interest or other payment in respect of any such delay), except
that, if such Business Day is in the next succeeding calendar year, such payment
shall be made on the immediately preceding Business Day, in each case with the
same force and effect as if made on such date.

                                       17
<PAGE>
 
     (c) If at any time the Trust is required to pay any taxes, duties,
assessments or governmental charges of whatever nature (other than withholding
taxes) imposed by the United States, or any other taxing authority, then, in any
such case, the Company will pay as additional sums ("Additional Sums") such
additional amounts as shall be required so that the net amounts received and
retained by the Trust after paying any such taxes, duties, assessments or other
governmental charges will not be less than the amounts the Trust would have
received had no such taxes, duties, assessments or other government charges been
imposed so long as the Trust is the holder of the Convertible Debentures.

     The definitive Convertible Debentures shall be printed, lithographed or
engraved on steel engraved borders or may be produced in any other manner, all
as determined by the officers executing such Convertible Debentures, as
evidenced by their execution of such Convertible Debentures.

     Section 2.6  Authentication and Delivery of Convertible Debentures.  At any
time and from time to time after the execution and delivery of this Indenture,
the Company may deliver Convertible Debentures in the aggregate principal amount
of up to $206,186,000 executed by the Company to the Trustee for authentication,
and the Trustee shall thereupon authenticate and make available for delivery
such Convertible Debentures to or upon the written order of the Company, signed
by both (i) the chairman of its Board of Directors, or any vice chairman of its
Board of Directors, or its president or any vice president and (ii) its
treasurer or any assistant treasurer or its secretary or any assistant
secretary, without any further action by the Company.  In authenticating such
Convertible Debentures and accepting the additional responsibilities under this
Indenture in relation to such Convertible Debentures, the Trustee shall be
entitled to receive and (subject to Section 6.1) shall be fully protected in
relying upon:

     (a) a copy of any resolution or resolutions of the Board of Directors
relating to the issuance of such Convertible Debentures, in each case certified
by the secretary or an assistant secretary of the Company;

     (b) a supplemental indenture, if any;

     (c) an Opinion of Counsel, prepared in accordance with Section 15.5, which
shall state that the Convertible Debentures have been duly authorized, and, when
authenticated and delivered by the Trustee and issued by the Company in the
manner and subject to any conditions specified in such Opinion of Counsel, will
constitute valid and binding obligations of the Company enforceable in
accordance with their terms, subject to applicable bankruptcy, insolvency,
fraudulent conveyance, reorganization or other laws relating to or affecting the
enforcement of creditors' rights generally and by general equitable principles,
regardless of whether such enforceability is considered in a proceeding in
equity or at law.

     Notwithstanding the provisions of the preceding paragraph, if the
Convertible Debentures are not to be originally issued at one time, it shall
not be necessary to deliver the resolution of the Board of Directors and Opinion
of Counsel otherwise required pursuant to such preceding paragraph at or prior
to the time of authentication of each Convertible Deben-

                                       18
<PAGE>
 
ture if such documents are delivered at or prior to the time of authentication
upon original issuance of the first Convertible Debentures to be issued.  After
the original issuance of the first Convertible Debenture to be issued, any
separate request by the Company that the Trustee authenticate Convertible
Debentures for original issuance will be deemed to be a certification by the
Company that it is in compliance with all conditions precedent provided for in
this Indenture relating to the authentication and delivery of such Convertible
Debentures.

     The Trustee shall have the right to decline to authenticate and deliver any
Convertible Debentures under this Section if the Trustee is advised by counsel
in good faith that the issuance of such Convertible Debentures would expose the
Trustee to personal liability or is unlawful.

     If the Convertible Debentures are to be issued in the form of one or more
Global Debentures, then the Company shall execute and the Trustee shall, in
accordance with this Section, authenticate and deliver one or more Global
Debentures that (i) shall represent and shall be denominated in an amount equal
to the aggregate principal amount of all of the Convertible Debentures issued
and not yet cancelled, (ii) shall be registered in the name of the Depositary
for such Global Debenture or Convertible Debentures or the nominee of such
Depositary, (iii) shall be delivered by the Trustee to such Depositary or
pursuant to such Depositary's instructions and (iv) shall bear a legend
substantially to the following effect:  "Unless and until it is exchanged in
whole or in part for Convertible Debentures in definitive registered form, this
Convertible Debenture may not be transferred except as a whole by the Depositary
to the nominee of the Depositary or by a nominee of the Depositary to the
Depositary or another nominee of the Depositary or by the Depositary or any such
nominee to a successor Depositary or a nominee of such successor Depositary."

     Each Depositary must, at the time of its designation and at all times while
it serves as Depositary, be a clearing agency registered under the Exchange Act
and any other applicable statute or regulation to be so registered to act as
such depositary.

     Section 2.7  Execution of Convertible Debentures.  The Convertible
Debentures shall be signed on behalf of the Company by the chairman of its Board
of Directors, or any vice chairman of its Board of Directors, or its president
or any vice president and attested by its treasurer or any assistant treasurer
or its secretary or any assistant secretary, under its corporate seal.  Such
signatures may be the manual or facsimile signatures of such officers.  The seal
of the Company may be in the form of a facsimile thereof and may be impressed,
affixed, imprinted or otherwise reproduced on the Convertible Debentures.
Typographical and other minor errors or defects in any such reproduction of the
seal or any such signature shall not affect the validity or enforceability of
any Convertible Debenture that has been duly authenticated and delivered by the
Trustee.

     In case any officer of the Company who shall have signed any of the
Convertible Debentures shall cease to be such officer before the Convertible
Debenture so signed shall be authenticated and delivered by the Trustee or
disposed of by the Company, such Convertible Debenture nevertheless may be
authenticated and delivered or disposed of as though the person who signed such
Convertible Debenture had not ceased to be such officer of the

                                       19
<PAGE>
 
Company; and any Convertible Debenture may be signed on behalf of the Company by
such persons as, at the actual date of the execution of such Convertible
Debenture, shall be the proper officers of the Company, although at the date of
the execution and delivery of this Indenture any such person was not such an
officer.

     Section 2.8  Certificate of Authentication.  Only such Convertible
Debentures as shall bear thereon a certificate of authentication substantially
in the form attached hereto as a part of Exhibit A and executed by the Trustee
by the manual signature of one of its authorized signatories shall be entitled
to the benefits of this Indenture or be valid or obligatory for any purpose.
The execution of such certificate by the Trustee upon any Convertible Debenture
executed by the Company shall be conclusive evidence that the Convertible
Debenture so authenticated has been duly authenticated and delivered hereunder
and that the Holder is entitled to the benefits of this Indenture.

     Notwithstanding the foregoing, if any Convertible Debenture shall have been
duly authenticated and delivered hereunder but never issued and sold by the
Company, the Company shall deliver such Convertible Debenture to the Trustee for
cancellation as provided in Section 2.12 together with a written statement
(which need not comply with Section 15.5 and need not be accompanied by an
Opinion of Counsel) stating that such Convertible Debenture has never been
issued and sold by the Company, for all purposes of this Indenture such
Convertible Debenture shall be deemed never to have been authenticated and
delivered hereunder and shall never be entitled to the benefits of this
Indenture.

     Section 2.9  Denomination and Date of Convertible Debentures; Payments of
Interest.  Convertible Debentures shall be issuable in denominations of $50 and
any integral multiple thereof.  The Convertible Debentures shall be numbered,
lettered, or otherwise distinguished in such manner or in accordance with such
plans as the officers of the Company executing the same may determine with the
approval of the Trustee as evidenced by the execution and authentication
thereof.

     Each Convertible Debenture shall be dated the date of its authentication.

     The term "record date" as used with respect to any interest payment date
(except for payment of defaulted interest) shall mean the close of business on
the fifteenth day preceding such interest payment date, whether or not such
record date is a Business Day.

     Any interest on any Convertible Debenture which is payable, but is not
punctually paid or duly provided for, on any interest payment date, subject to
the provisions of Article XI (called "defaulted interest" for purposes of this
Section) shall forthwith cease to be payable to the Holder on the relevant
record date by virtue of his having been such Holder; and such defaulted
interest may be paid by the Company, at its election in each case, as provided
in clause (1) or clause (2) below:

          (1) The Company may elect to make payment of any defaulted interest to
     the persons in whose names any such Convertible Debentures (or their
     respective predecessor Convertible Debentures) are registered at the close
     of business on a special

                                       20
<PAGE>
 
     special record date for the payment of such defaulted interest, which shall
     be fixed in the following manner. The Company shall notify the Trustee in
     writing of the amount of defaulted interest proposed to be paid on each
     Convertible Debentures and the date of the proposed payment, and at the
     same time the Company shall deposit with the Trustee an amount of money
     equal to the aggregate amount proposed to be paid in respect of such
     defaulted interest or shall make arrangements satisfactory to the Trustee
     for such deposit prior to the date of the proposed payment, such money when
     deposited to be held in trust for the benefit of the persons entitled to
     such defaulted interest as in this clause provided. Thereupon the Trustee
     shall fix a special record date for the payment of such defaulted interest
     in respect of Convertible Debentures which shall not be more than 15 nor
     less than 10 days prior to the date of the proposed payment and not less
     than 10 days after the receipt by the Trustee of the notice of the proposed
     payment. The Trustee shall promptly notify the Company of such special
     record date and, in the name and at the expense of the Company shall cause
     notice of the proposed payment of such defaulted interest and the special
     record date thereof to be mailed, first class postage prepaid, to each
     Holder at his address as it appears in the Security Register, not less than
     10 days prior to such special record date. Notice of the proposed payment
     of such defaulted interest and the special record date therefor having been
     mailed as aforesaid, such defaulted interest in respect of Convertible
     Debentures shall be paid to the person in whose names such Convertible
     Debentures (or their respective predecessor Convertible Debentures) are
     registered on such special record date and such defaulted interest shall no
     longer be payable pursuant to the following clause (2).

          (2)  The Company may make payment of any defaulted interest on the
     Convertible Debentures in any other lawful manner not inconsistent with the
     requirements of any securities exchange on which the Convertible Debentures
     may be listed, and upon such notice as may be required by such exchange,
     if, after notice given by the Company to the Trustee of the proposed
     payment pursuant to this clause, such manner of payment shall be deemed
     practicable by the Trustee.

     Subject to the foregoing provisions of this Section, each Convertible
Debenture delivered under this Indenture upon transfer of or in exchange for or
in lieu of any other Convertible Debenture shall carry the rights to interest
accrued and unpaid, and to accrue, which were carried by such other Convertible
Debenture.

     In the case of any Convertible Debenture which is converted into Common
Stock of the Company after any record date and on or prior to the next
succeeding Interest Payment Date (other than any Convertible Debenture whose
Maturity is prior to such Interest Payment Date), interest whose Stated Maturity
is on such Interest Payment Date shall be payable on such Interest Payment Date
notwithstanding such conversion, and such interest (whether or not punctually
paid or duly provided for) shall be paid to the Person in whose name that
Convertible Debenture (or one or more Predecessor Convertible Debentures) is
registered at the close of business on such record date.  However, if a
redemption date falls between a record date and the subsequent Interest Payment
Date, the amount of such payment shall include accumulated and unpaid interest
accrued to, but excluding, such redemption date.

                                       21
<PAGE>
 
Except as otherwise expressly provided in the first two sentences of this
paragraph, in the case of any Convertible Debenture which is converted, interest
whose Stated Maturity is after the date of conversion of such Convertible
Debenture shall not be payable.

     Section 2.10  Registration, Transfer and Exchange.  The provisions of this
Section 2.10 shall be subject in their entirety to the provisions of Section
2.4.  The Company will cause to be kept at each office or agency to be
maintained for the purpose as provided in Section 3.2 a register or registers
(herein sometimes referred to as the "Security Register") in which, subject to
such reasonable regulations as it may prescribe, the Company will provide for
the registration and the registration of the transfer or exchange of the
Convertible Debentures.  The Trustee is hereby appointed and accepts the
appointment as Registrar (the "Registrar") for purposes of registering, and
registering transfers of, the Convertible Debentures.

     Upon surrender for registration of transfer of any Convertible Debenture at
any such office or agency to be maintained for the purpose as provided in
Section 3.2, the Company shall execute and the Trustee shall authenticate and
make available for delivery in the name of the transferee or transferees a new
Convertible Debenture or Convertible Debentures and of a like tenor and
containing the same terms (other than the principal amount thereof, if more than
one Convertible Debenture is executed, authenticated and delivered in respect to
any Convertible Debenture so presented, in which case the aggregate principal
amount of the executed, authenticated and delivered Convertible Debentures shall
equal the principal amount of the Convertible Debenture presented in respect
thereof) and conditions.

     At the option of the Holder thereof, Convertible Debentures (other than a
Global Debenture, except as set forth below) may be exchanged for a Convertible
Debenture or Convertible Debentures having authorized denominations and an equal
aggregate principal amount, upon surrender of such Convertible Debentures to be
exchanged at the agency of the Company that shall be maintained for such purpose
in accordance with Section 3.2 and upon payment, if the Company shall so
require, of the charge hereinafter provided.  Whenever any Convertible
Debentures are so surrendered for exchange, the Company shall execute, and the
Trustee shall authenticate and deliver, the Convertible Debentures which the
Holder making the exchange is entitled to receive.  All Convertible Debentures
surrendered upon any exchange or transfer provided for in this Indenture shall
be promptly cancelled by the Trustee and the Trustee will deliver a certificate
of cancellation thereof to the Company.

     All Convertible Debentures issued upon any transfer or exchange of
Convertible Debentures shall be the valid obligations of the Company, evidencing
the same debt, and entitled to the same benefits under this Indenture, as the
Convertible Debentures surrendered upon such transfer or exchange.

     Every Convertible Debenture presented or surrendered for registration of
transfer or exchange shall (if so required by the Company or the Trustee) be
duly endorsed, or be accompanied by a written instrument of transfer in form
satisfactory to the Company and the Trustee duly executed by the Holder thereof
or his attorney duly authorized in writing.

                                       22
<PAGE>
 
     No service charge shall be made to the Holder for any registration of
transfer or exchange of Convertible Debentures, but the company may require
payment of a sum sufficient to cover any tax or other governmental charge that
may be imposed in connection with any transfer or exchange of Convertible
Debentures, other than exchanges pursuant to Sections 2.13, 8.5 or 12.5 not
involving any transfer.

     The Company shall not be required (i) to issue, register the transfer of or
exchange any Convertible Debenture during a 15-day period prior to the day of
mailing of the relevant notice of redemption or (ii) to register the transfer of
or exchange any Convertible Debenture so selected for redemption in whole or in
part, except, in the case of any Convertible Debenture to be redeemed in part,
the portion thereof not redeemed.

     Notwithstanding any other provisions of this Section 2.10, unless and until
it is exchanged in whole or in part for Convertible Debentures in definitive
registered form, a Global Debenture representing all or a portion of the
Convertible Debentures may not be transferred except as a whole by the
Depositary to a nominee of such Depositary or by a nominee of such Depositary to
such Depositary or another nominee of such Depositary or by such Depositary or
any such nominee to a successor Depositary or a nominee of such successor
Depositary.

     If at any time the Depositary for any Convertible Debentures represented by
one or more Global Debentures notifies the Company that it is unwilling or
unable to continue as Depositary for such Convertible Debentures or if at any
time the Depositary for such Convertible Debentures shall no longer be eligible
under Section 2.6, the Company shall appoint a successor Depositary with respect
to such Convertible Debentures.  If a successor Depositary for such Convertible
Debentures is not appointed by the Company within 90 days after the Company
receives such notice or becomes aware of such ineligibility, as the case may be,
the Company's election that such Convertible Debentures be represented by one or
more Global Debentures shall no longer be effective and the Company will
execute, and the Trustee, upon receipt of an Officers' Certificate for the
authentication and delivery of definitive Convertible Debentures, will
authenticate and deliver, Convertible Debentures in definitive registered form,
in any authorized denominations, in an aggregate principal amount equal to the
principal amount of the Global Debenture or Convertible Debentures representing
such Convertible Debentures in exchange for such Global Debenture or Convertible
Debentures.

     The Company may at any time and in its sole discretion determine that the
Convertible Debentures issued in the form of one or more Global Debentures shall
no longer be represented by a Global Debenture.  In such event the Company will
execute, and the Trustee, upon receipt of an Officers' Certificate for the
authentication and delivery of definitive Convertible Debentures, will
authenticate and deliver, Convertible Debentures in definitive registered form,
in any authorized denominations, in an aggregate principal amount equal to the
principal amount of the Global Debenture, in exchange for such Global Debenture.

                                       23
<PAGE>
 
     If an Event of Default occurs and is continuing with respect to Convertible
Debentures issued in the form of one or more Global Debentures, upon written
notice from the Depositary, the Company will execute, and the Trustee, upon
receipt of an Officers' Certificate for the authentication and delivery of
definitive Convertible Debentures, will authenticate and deliver, Convertible
Debentures in definitive registered form, in any authorized denominations, in an
aggregate principal amount equal to the principal amount of the Global Debenture
or Convertible Debentures, representing such Convertible Debentures, in exchange
for such Global Debenture or Convertible Debentures.

     If specified by the Company, the Depositary for such Global Debenture may
surrender such Global Debenture in exchange in whole or in part for Convertible
Debentures in definitive registered form on such terms as are acceptable to the
Company and such Depositary.  Thereupon, the Company shall execute, and the
Trustee shall authenticate and deliver, without service charge to the Holder,

          (i) to the Person specified by such Depositary a new Convertible
     Debenture or Convertible Debentures, of any authorized denominations as
     requested by such Person, in an aggregate principal amount equal to and in
     exchange for such Person's beneficial interest in the Global Debenture; and

          (ii) to such Depositary a new Global Debenture in a denomination equal
     to the difference, if any, between the principal amount of the surrendered
     Global Debenture and the aggregate principal amount of Convertible
     Debentures authenticated and delivered pursuant to clause (i) above.

     Upon the exchange of a Global Debenture for Convertible Debentures in
definitive registered form, in authorized denominations, such Global Debenture
shall be cancelled by the Trustee or an agent of the Company or the Trustee.
Convertible Debentures in definitive registered form issued in exchange for a
Global Debenture pursuant to this Section 2.10 shall be registered in such names
and in such authorized denominations as the Depositary for such Global
Debenture, pursuant to instructions from its direct or indirect participants or
otherwise, shall instruct the Trustee or agent of the Company or the Trustee.
The Trustee or such agent shall deliver such Convertible Debentures to or as
directed by the Persons in whose names such Convertible Debentures are so
registered.

     Section 2.11  Mutilated, Defaced, Destroyed, Lost and Stolen Convertible
Debentures.  In case any temporary or definitive Convertible Debenture shall
become mutilated or defaced or be destroyed, lost or stolen, then, in the
absence of notice to the Company or the Trustee that the Convertible Debenture
has been acquired by a bona fide purchaser, the Company shall execute, and upon
the written request of any officer of the Company, the Trustee shall
authenticate and make available for delivery a new Convertible Debenture and of
like tenor and principal amount and with the same terms and conditions, bearing
a number not contemporaneously outstanding, in exchange and substitution for the
mutilated or defaced Convertible Debenture or in lieu of and substitution for
the Convertible Debenture so destroyed, lost or stolen.  In every case the
applicant for a substitute Convertible Debenture shall furnish to the Company
and to the Trustee and to any agent of the Company or the 

                                       24
<PAGE>
 
Trustee such security or indemnity as may be required by them to indemnify and
defend and to save each of them harmless and, in every case of destruction, loss
or theft, evidence to their satisfaction of the destruction, loss or theft of
such Convertible Debenture and of the ownership thereof and in the case of
mutilation or defacement shall surrender the Convertible Debenture to the
Trustee or such agent.

     Upon the issuance of any substitute Convertible Debenture, the Company may
require the payment of a sum sufficient to cover any tax or other governmental
charge that may be imposed in relation thereto and any other expenses (including
the fees and expenses of the Trustee or its agent) connected therewith.  In case
any Convertible Debenture which has matured or is about to mature or has been
called for redemption in full shall become mutilated or defaced or be destroyed,
lost or stolen, the Company may, instead of issuing a substitute Convertible
Debenture, pay or authorize, the payment of the same (without surrender thereof
except in the case of a mutilated or defaced Convertible Debenture); provided,
however, that the applicant for such payment shall furnish to the Company and to
the Trustee and any agent of the Company or the Trustee such security or
indemnity as any of them may require to save each of them harmless, and, in
every case of destruction, loss or theft, the applicant shall also furnish to
the Company and the Trustee and any agent of the Company or the Trustee evidence
to their satisfaction of the destruction, loss or theft of such Convertible
Debenture and of the ownership thereof.

     Every substitute Convertible Debenture issued pursuant to the provisions of
this Section by virtue of the fact that any Convertible Debenture is destroyed,
lost or stolen shall constitute an additional contractual obligation of the
Company, whether or not the destroyed, lost or stolen Convertible Debenture
shall be at any time enforceable by anyone and shall be entitled to all the
benefits of (but shall be subject to all the limitations of rights set forth in)
this Indenture equally and proportionately with any and all other Convertible
Debentures duly authenticated and delivered hereunder.  All Convertible
Debentures shall be held upon the express condition that, to the extent
permitted by law, the foregoing provisions are exclusive with respect to the
replacement or payment of mutilated, defaced, destroyed, lost or stolen
Convertible Debentures and shall preclude any and all other rights or remedies
notwithstanding any law or statute existing or hereafter enacted to the
contrary with respect to the replacement or payment of negotiable instruments or
other securities without their surrender.

     Section 2.12  Cancellation of Convertible Debentures.  All Convertible
Debentures surrendered for payment, redemption, conversion, registration of
transfer or exchange, or for credit against any payment in respect of a sinking
or analogous fund, shall, if surrendered to the Company or any agent of the
Company or the Trustee, be delivered to the Trustee for cancellation or, if
surrendered to the Trustee, shall be cancelled by it; and no Convertible
Debentures shall be issued in lieu thereof, except as expressly permitted by any
of the provisions of this Indenture.  The Company may at any time deliver to the
Trustee for cancellation any Convertible Debentures previously authenticated
hereunder which the Company has not issued and sold and all Convertible
Debentures so delivered shall be promptly cancelled by the Trustee.  If the
Company shall acquire any of the Convertible Debentures, such acquisition shall
not operate as a redemption or satisfaction of the indebtedness represented by
such Convertible Debentures unless and until the same are 

                                       25
<PAGE>
 
delivered to the Trustee for cancellation. All cancelled Convertible Debentures
shall be disposed of as directed by a Company Order or, in the absence of such
Company Order, in accordance with the Trustee's customary practices. The Trustee
shall provide a certificate of destruction to the Company with respect to all
Convertible Debentures disposed of by the Trustee.

     Section 2.13  Temporary Convertible Debentures.  Pending the preparation of
definitive Convertible Debentures, the Company may execute and the Trustee shall
authenticate and make available for delivery temporary Convertible Debentures
(printed, lithographed, typewritten or otherwise reproduced, in each case in
form reasonably acceptable to the Trustee).  Temporary Convertible Debentures
shall be issuable in any authorized denomination, and substantially in the form
of the definitive Convertible Debentures but with such omissions, insertions and
variations as may be appropriate for temporary Convertible Debentures, all as
may be determined by the Company with the reasonable concurrence of the Trustee.
Temporary Convertible Debentures may contain such reference to any provisions of
this Indenture as may be appropriate.  Every temporary Convertible Debenture
shall be executed by the Company and be authenticated by the Trustee upon the
same conditions and in substantially the same manner, and with like effect, as
the definitive Convertible Debentures.  Without unreasonable delay the Company
shall execute and shall furnish definitive Convertible Debentures and thereupon
temporary Convertible Debentures may be surrendered in exchange therefor without
charge to the Holder at each office or agency to be maintained by the Company
for that purpose pursuant to Section 3.2, and the Trustee shall authenticate and
make available for delivery in exchange for such temporary Convertible
Debentures an equal aggregate principal amount of definitive Convertible
Debentures of authorized denominations.  Until so exchanged, the temporary
Convertible Debentures shall be entitled to the same benefits under this
Indenture as definitive Convertible Debentures.


                                  ARTICLE III

                           COVENANTS OF THE COMPANY

     Section 3.1  Payment of Principal and Interest.  The Company covenants and
agrees for the benefit of the Convertible Debentures that it will duly and
punctually pay or cause to be paid the principal of, and interest on, each of
the Convertible Debentures in accordance with the terms of such Convertible
Debentures and of this Indenture.  The interest on Convertible Debentures
(together with any additional amounts payable pursuant to the terms of such
Convertible Debentures) shall be payable only to or upon the written order of
the Holders thereof and at the option of the Company may be paid by wire
transfer or by mailing checks for such interest payable to or upon the written
order of such Holders at their last addresses as they appear on the Security
Register.

     Payment of principal of and any interest on any Convertible Debenture in
definitive global form shall be made to the Person or Persons specified therein.

                                       26
<PAGE>
 
     Except as provided in the preceding paragraph, the Company, the Trustee and
any agent of the Company and the Trustee shall treat a Person as the Holder of
such principal amount of Outstanding Convertible Debentures represented by a
Global Debenture as shall be specified in a written statement of the Holder of
such Global Debenture.

     Section 3.2  Offices for Payment, etc.  So long as any of the Convertible
Debentures remain outstanding, the Company will maintain the following:  an
office or agency in the Borough of Manhattan, City of New York (a) where the
Convertible Debentures may be presented for payment, (b) where the Convertible
Debentures may be presented for registration of transfer and for exchange as
provided in this Indenture, and (c) where notices and demands may be served upon
the Company in respect of the Convertible Debentures, or this Indenture.

     The Company will give to the Trustee written notice of the location of any
such office or agency and of any change of location thereof.  In case the
Company shall fail to so designate or maintain any such office or agency or
shall fail to give such notice of the location or of any change in the location
thereof, presentations and demands may be made and notices may be served at the
Corporate Trust Office.  The Trustee is hereby appointed, and accepts its
appointment as, Paying Agent.

     Section 3.3  Paying Agents.  Whenever the Company shall appoint a Paying
Agent other than the Trustee with respect to the Convertible Debentures, it will
cause such Paying Agent to execute and deliver to the Trustee an instrument in
which such Paying Agent shall agree with the Trustee, subject to the provisions
of this Section:

          (a)  that it will hold all sums received by it as such Paying Agent
     for the payment of the principal of or interest on the Convertible
     Debentures (whether such sums have been paid to it by the Company or by any
     other obligor on the Convertible Debentures) in trust for the benefit of
     the Holders of the Convertible Debentures or of the Trustee, and upon the
     occurrence of an Event of Default and upon the written request of the
     Trustee, pay over all such sums received by it to the Trustee; and

          (b)  that it will give the Trustee notice of any failure by the
     Company (or by any other obligor on the Convertible Debentures) to make any
     payment of the principal of or interest on the Convertible Debentures when
     the same shall be due and payable.

     The Company will, on or prior to each due date of the principal of or
interest on the Convertible Debentures, deposit in a timely manner with the
Paying Agent a sum sufficient to pay such principal or interest so becoming due,
and (unless such Paying Agent is the Trustee) the Company will promptly notify
the Trustee of any failure to take such action.

     If the Company shall act as its own Paying Agent with respect to the
Convertible Debentures, it will, on or before each due date of the principal of
or interest on the Convertible Debentures, set aside, segregate and hold in
trust for the benefit of the holders

                                       27
<PAGE>
 
of the Convertible Debentures a sum sufficient to pay such principal or interest
so becoming due. The Company will promptly notify the Trustee of any failure to
take such action.

     Section 3.4  Written Statement to Trustee.  The Company will deliver to the
Trustee, within 120 days after the end of each fiscal year of the Company ending
after the date hereof, a brief certificate (which need not comply with Section
15.5) from the principal executive, financial or accounting officer of the
Company as to his or her knowledge, after due inquiry, of the Company's
compliance with all conditions and covenants under this Indenture (such
compliance to be determined without regard to any period of grace or requirement
of notice provided under this Indenture), and if the Company shall not be in
compliance, specifying all such defaults or non-compliance and the nature and
status thereof.

     Section 3.5  Limitation on Dividends; Transactions with Affiliates.  If any
Convertible Debentures are outstanding and (i) there shall have occurred any
Event of Default or any event that, with the giving of notice or lapse of time
or both, would constitute an Event of Default, (ii) the Guarantor shall be in
default with respect to its payment or other obligations under the Preferred
Securities Guarantee or the Common Securities Guarantee, or (iii) the Company
shall have given notice of its election to defer payments of interest on
Convertible Debentures by extending the interest payment period as provided in
Article XI and such period, or any extension thereof, shall be continuing, then
the Company shall not (a) declare or pay any dividend on, make any distribution
with respect to, or redeem, purchase or make a liquidation payment with respect
to, any of its Capital Stock or (b) make any payment of interest, principal or
premium, if any, on or repay, repurchase or redeem any debt securities issued by
the Company that rank pari passu with or junior in interest to the Convertible
Debentures or make any guarantee payments with respect to any guarantee by the
Company of the debt securities of any subsidiary of the Company if such
guarantee ranks pari passu with or junior in interest to the Convertible
Debentures (other than (i) as a result of a reclassification of the Capital
Stock of the Company or the exchange or conversion of one class or series of the
Capital Stock of the Company for another class or series of the Capital Stock of
the Company, (ii) the purchase of fractional interests in shares of the Capital
Stock of the Company pursuant to the conversion or exchange provisions of such
Capital Stock or the security being converted into or exchanged for such Capital
Stock, (iii) dividends or distributions in Common Stock of the Company, (iv) any
declaration of a dividend in connection with the implementation of a
stockholders' rights plan, or the issuance of stock under any such plan in the
future, or the redemption or repurchase of any such rights pursuant thereto, (v)
payments under the Trust Securities Guarantees, (vi) purchases of Common Stock
of the Company related to the issuance of Common Stock of the Company or rights
under any of the Company's benefit plans for its directors, officers or
employees and (vii) obligations under any dividend reinvestment and stock
purchase plans).

     Section 3.6  Covenants as to McKesson Trust.  For so long as the Trust
Securities remain outstanding, the Company will (a) maintain 100% direct or
indirect ownership of the Common Securities of McKesson Trust; provided,
however, that any permitted successor of the Company under this Indenture may
succeed to the Company's ownership of the Common Securities, (b) use its
reasonable efforts to cause McKesson Trust (i) to remain a statutory business
trust, except in connection with the distribution of Convertible Debentures to
the 

                                       28
<PAGE>
 
holders of Trust Securities in liquidation of McKesson Trust, the redemption of
all of the Trust Securities of McKesson Trust, or certain mergers,
consolidations or amalgamations, each as permitted by the Declaration, and (ii)
to continue to be classified as a grantor trust for United States federal income
tax purposes and (c) to use its reasonable efforts to cause each holder of Trust
Securities to be treated as owning an undivided beneficial interest in the
Convertible Debentures.

     Section 3.7  Existence.  Subject to Article IX, the Company will do or
cause to be done all things necessary to preserve and keep in full force and
effect its existence, rights (charter and statutory) and franchises; provided,
however, that the Company shall not be required to preserve any such right or
franchise if the Board of Directors shall determine that the preservation
thereof is no longer desirable in the conduct of the business of the Company and
that the loss thereof is not disadvantageous in any material respect to the
Holders.


                                  ARTICLE IV

              HOLDERS OF CONVERTIBLE DEBENTURES LISTS AND REPORTS
                        BY THE COMPANY AND THE TRUSTEE

     Section 4.1  Company to Furnish Trustee Information as to Names and
Addresses of Holders of Convertible Debentures.  The Company covenants and
agrees that it will furnish or cause to be furnished to the Trustee a list in
such form as the Trustee may reasonably require of the names and addresses of
the Holders of the Convertible Debentures:

          (a)  semiannually and not more than 15 days after each record date for
     the payment of interest on such Convertible Debentures, as hereinabove
     specified, as of such record date, and

          (b)  at such other times as the Trustee may reasonably request in
     writing, within 30 days after receipt by the Company of any such request,
     such list to be as of a date not more than 15 days prior to the time such
     information is furnished,

provided that if and so long as the Trustee shall be the Registrar, such list
shall not be required to be furnished.

     Section 4.2  Preservation and Disclosure of Holders of Convertible
Debentures' Lists.

     (a)  The Trustee shall preserve, in as current a form as is reasonably
practicable, all information as to the names and addresses of the Holders of
Convertible Debentures contained in the most recent list furnished to it as
provided in Section 4.1 or maintained by the Trustee in its capacity as
Registrar, if so acting.  The Trustee may destroy any list furnished to it as
provided in Section 4.1 upon receipt of a new list so furnished.

     (b)  In case three or more Holders of Convertible Debentures (hereinafter
referred to as "applicants") apply in writing to the Trustee and furnish to the
Trustee reasonable proof 

                                       29
<PAGE>
 
that each such applicant has owned a Convertible Debenture for a period of at
least six months preceding the date of such application, and such application
states that the applicants desire to communicate with other Holders of
Convertible Debentures (in which case the applicants must all hold Convertible
Debentures) or with Holders of all Convertible Debentures with respect to their
rights under this Indenture or under such Convertible Debentures and such
application is accompanied by a copy of the form of proxy or other communication
which such applicants propose to transmit, then the Trustee shall, within five
business days after the receipt of such application, at is election, either

          (i)  afford to such applicants access to the information preserved at
     the time by the Trustee in accordance with the provisions of subsection (a)
     of this Section, or

          (ii) inform such applicants as to the approximate number of Holders of
     Convertible Debentures or of all Convertible Debentures, as the case may
     be, whose names and addresses appear in the information preserved at the
     time by the Trustee, in accordance with the provisions of subsection (a) of
     this Section, as to the approximate cost of mailing to such Holders of
     Convertible Debentures the form of proxy or other communication, if any,
     specified in such application.

     If the Trustee shall elect not to afford to such applicants access to such
information, the Trustee shall, upon the written request of such applicants,
mail to each Holder of Convertible Debentures or all Holders of Convertible
Debentures, as the case may be, whose name and address appears in the
information preserved at the time by the Trustee in accordance with the
provisions of subsection (a) of this Section, a copy of the form of proxy or
other communication which is specified in such request, with reasonable
promptness after a tender to the Trustee of the material to be mailed and of
payment, or provision for the payment, of the reasonable expenses of mailing,
unless within five days after such tender, the Trustee shall mail to such
applicants and file with the Commission together with a copy of the material to
be mailed, a written statement to the effect that, in the opinion of the
Trustee, such mailing would be contrary to the best interests of the Holders of
Convertible Debentures or could be in violation of applicable law.  Such written
statement shall specify the basis of such opinion.  If the Commission, after
opportunity for a hearing upon the objections specified in the written statement
so filed, shall enter an order refusing to sustain any of such objections or if,
after the entry of such order sustaining one or more of such objections, the
Commission shall find, after notice and opportunity for hearing, that all the
objections so sustained have been met, and shall enter an order so declaring,
the Trustee shall mail copies of such material to all such Holders of
Convertible Debentures with reasonable promptness after the entry of such order
and the renewal of such tender; otherwise the Trustee shall be relieved of any
obligation or duty to such applicants respecting their application.

     (c)  Each and every Holder of Convertible Debentures, by receiving and
holding the same, agrees with the Company and the Trustee that neither the
Company nor the Trustee nor any agent of the Company or the Trustee shall be
held accountable by reason of the disclosure of any such information as to the
names and addresses of the Holders of Convertible Debentures in accordance with
the provisions of subsection (b) of this Section, regardless of the source from
which such information was derived, and that the Trustee shall

                                       30
<PAGE>
 
not be held accountable by reason of mailing any material pursuant to a request
made under such subsection (b).

     Section 4.3  Reports by the Company.  The Company covenants:

          (a)  to file with the Trustee, within 15 days after the Company is
     required to file the same with the Commission, copies of the annual reports
     and of the information, documents, and other reports (or copies of such
     portions and any of the foregoing as the Commission may from time to time
     by rules and regulations prescribe) which the Company may be required to
     file with the Commission pursuant to Section 13 or Section 15(d) of the
     Exchange Act, or if the Company is not required to file information,
     documents, or reports pursuant to either of such Sections, then to file
     with the Trustee and the Commission to the extent permitted, in accordance
     with rules and regulations prescribed from time to time by the Commission,
     such of the supplemen tary and periodic information, documents, and reports
     which may be required pursuant to Section 13 of the Exchange Act, in
     respect of a security listed and registered on a national securities
     exchange as may be prescribed from time to time in such rules and
     regulations;

          (b)  to file with the Trustee and the Commission, in accordance with
     rules and regulations prescribed from time to time by the Commission, such
     additional information, documents, and reports with respect to compliance
     by the Company with the conditions and covenants provided for in this
     Indenture as may be required from time to time by such rules and
     regulations; and

          (c)  to transmit by mail to the Holders of Convertible Debentures in
     the manner and to the extent required by Sections 6.6 and 15.4, within 30
     days after the filing thereof with the Trustee, such summaries of any
     information, documents, and reports required to be filed by the Company
     pursuant to subsections (a) and (b) of this Section as may be required to
     be transmitted to such Holders by rules and regulations prescribed from
     time to time by the Commission.


                                   ARTICLE V

                    REMEDIES OF THE TRUSTEE AND HOLDERS OF
                  CONVERTIBLE DEBENTURES ON EVENT OF DEFAULT

     Section 5.1  Event of Default Defined; Acceleration of Maturity; Waiver of
Default.  "Event of Default" with respect to the Convertible Debentures wherever
used herein, means any one or more of the following events which shall have
occurred and be continuing (whatever the reason for such Event of Default and
whether it shall be voluntary or involuntary or be effected by operation of law
or pursuant to any judgment, decree or order of any court or any order, rule or
regulation of any administrative or governmental body):

                                       31
<PAGE>
 
          (a)  default in the payment of any interest (including any Additional
     Sums and Compound Interest) upon or any additional amounts, including any
     Liquidated Damages Amount (as defined in the Preferred Securities
     Registration Rights Agreement), payable in respect of any Convertible
     Debentures when it becomes due and payable, and continuance of such default
     for a period of 30 days; provided, however, that a valid extension of an
     interest payment period by the Company in accordance with the terms of this
     Indenture shall not constitute a default in the payment of interest for
     this purpose; or

          (b)  default in the payment of the principal of, or premium, if any,
     on, any Convertible Debentures as and when the same shall become due and
     payable whether at maturity, upon redemption, by declaration or otherwise;
     or

          (c)  default in the performance, or breach of any covenant or warranty
     of the Company contained in the Convertible Debentures or in this Indenture
     (other than a covenant or warranty a default in whose performance or whose
     breach is elsewhere in this Section specifically dealt with), and
     continuance of such default or breach for a period of 30 days after there
     has been given, by registered or certified mail, to the Company by the
     Trustee or to the Company and the Trustee by the Holders of at least 25% in
     aggregate principal amount of the Outstanding Convertible Debentures a
     written notice specifying such default or breach and requiring it to be
     remedied and stating that such notice is a "Notice of Default" hereunder;
     or

          (d)  the entry by a court having jurisdiction in the premises of (A) a
     decree or order for relief in respect of the Company in an involuntary case
     or proceeding under any applicable federal or state bankruptcy, insolvency,
     reorganization or other similar law or (B) a decree or order adjudging the
     Company a bankrupt or insolvent, or approving as properly filed a petition
     seeking reorganization, arrangement, adjust ment or composition of or in
     respect of the Company under any applicable federal or state law, or
     appointing a custodian, receiver, liquidator, assignee, trustee,
     sequestrator or other similar official of the Company or of all or any
     substantial part of its property, or ordering the winding up or liquidation
     of its affairs, and the continuance of any such decree or order for relief
     or any such other decree or order unstayed and in effect for a period of 90
     consecutive days; or

          (e) the commencement by the Company of a voluntary case or proceeding
     under any applicable federal or state bankruptcy, insolvency,
     reorganization or other similar law or of any other case or proceeding to
     be adjudicated a bankrupt or insolvent, or the consent by it to the entry
     of a decree or order for relief in respect of the Company in an involuntary
     case or proceeding under any applicable federal or state bankruptcy,
     insolvency, reorganization or other similar law or to the commence ment of
     any bankruptcy or insolvency case or proceeding against it, or the filing
     by it of a petition or answer or consent seeking reorganization or relief
     under any applicable federal or state law, or the consent by it to the
     filing of such petition or to the appointment of or taking possession by a
     custodian, receiver, liquidator, assignee, trustee, sequestrator or similar
     official of the Company or of all or any substantial

                                       32
<PAGE>
 
     part of its property, or the making by it of an assignment for the benefit
     of creditors, or the admission by it in writing of its inability to pay its
     debts generally as they become due, or the taking of corporate action by
     the Company in furtherance of any such action; or

          (f)  failure by the Company to convert Convertible Debentures into
     shares of Common Stock of the Company upon an appropriate election by a
     holder of Trust Securities or Convertible Debentures to convert such Trust
     Securities or Convertible Debentures, as the case may be, into such Common
     Stock (whether or not conversion or exchange is prohibited by the
     subordination provisions set forth herein); or

          (g)  the McKesson Trust shall have voluntarily or involuntarily
     dissolved, wound-up its business or otherwise terminated its existence
     except in connection with (i) the distribution of Convertible Debentures to
     holders of Trust Securities in liquidation of their interest in the
     McKesson Trust upon the occurrence of a Special Event or upon the
     occurrence of events as described in Section 3 of Annex I to the
     Declaration, (ii) the redemption of all of the outstanding Trust Securities
     of the McKesson Trust, (iii) the conversion of all outstanding Convertible
     Preferred Securities into Common Stock of the Company or (iv) certain
     mergers, consolidations or amalgamations, each as permitted by the
     Declaration.

     If an Event of Default occurs and is continuing, then and in each and every
such case, unless the principal of all Convertible Debentures shall have already
become due and payable, either the Trustee or the Holders of not less than 25%
in aggregate principal amount of the Convertible Debentures then Outstanding
hereunder, by notice in writing to the Company (and to the Trustee if given by
such Holders), may declare the entire principal of, plus accrued and unpaid
interest on, all the Convertible Debentures (including Additional Sums, if any,
and, to the extent permitted by applicable law, Compound Interest, if any) and
any other amounts payable under this Indenture to be due and payable
immediately, and upon any such declaration the same shall become and shall be
immediately due and payable.  These provisions, however, are subject to the
condition that if at any time after the principal and other amounts due on the
Convertible Debentures shall have been so declared due and payable, and before
any judgment or decree for the payment of the moneys due shall have been
obtained or entered as hereinafter provided, the Company shall pay or shall
deposit with the Trustee a sum sufficient to pay all matured installments of
interest, if any, upon all the Convertible Debentures and the principal of any
and all Convertible Debentures which shall have become due otherwise than by
such acceleration (with interest upon such principal and, to the extent that
payment of such interest is enforceable under applicable law, Compound Interest
to the date of such payment or deposit in Dollars such amount as shall be
sufficient to cover reasonable compensation to the Trustee, its agents,
attorneys and counsel and all other expenses and liabilities incurred, and all
advances with interest made, by the Trustee, its agents, attorneys and counsel
and if any and all defaults under this Indenture, other than the nonpayment of
the principal and interest of Convertible Debentures which shall have become due
by such acceleration, shall have been cured or waived as provided herein, then
and in every such case the Holders of a majority in aggregate principal amount
of the Convertible Debentures then Outstanding, by written notice to the Company
and to the 

                                       33
<PAGE>
 
Trustee for the Convertible Debentures, may waive all defaults and rescind and
annul such declaration and its consequences; but no such waiver or rescission
and annulment shall extend to or shall affect any subsequent default or shall
impair any right consequent thereon.

     Section 5.2  Collection of Indebtedness by Trustee; Trustee May Prove Debt.
The Company covenants that (a) in case default shall be made in the payment of
any installment of interest on any of the Convertible Debentures when such
interest shall have become due and payable, and such default shall have
continued for a period of 30 days, or (b) in case default shall be made in the
payment of all or any part of the principal of any of the Convertible Debentures
when the same shall have become due and payable, whether upon Maturity or upon
any redemption or by declaration or otherwise, then upon demand of the Trustee
for the Convertible Debentures, the Company will pay to the Trustee for the
benefit of the Holders of the Convertible Debentures the whole amount that then
shall have become due and payable on all Convertible Debentures for principal of
or interest, as the case may be (with interest to the date of such payment upon
the overdue principal and, to the extent that payment of such interest is
enforceable under applicable law, on overdue installments of interest at the
same rate as the rate of interest specified in the Convertible Debentures); and
in addition thereto, such further amount as shall be sufficient to cover the
costs and expenses of collection, including reasonable compensation to, and all
expenses and liabilities incurred and all advances with interest made by, the
Trustee and each predecessor Trustee except as a result of its negligence or bad
faith.

     Until such demand is made by the Trustee, the Company may pay the principal
of and interest on the Convertible Debentures to the persons entitled thereto,
whether or not the principal of and interest on the Convertible Debentures are
overdue.

     In case the Company shall fail forthwith to pay such amounts upon such
demand, the Trustee for the Convertible Debentures, in its own name and as
trustee of an express trust, shall be entitled and empowered to institute any
action or proceedings at law or in equity for the collection of the sums so due
and unpaid, and may prosecute any such action or proceedings to judgment or
final decree, and may enforce any such judgment or final decree against the
Company or other obligor upon such Convertible Debentures and collect in the
manner provided by law out of the property of the Company or other obligor upon
such Convertible Debentures, wherever situated, the moneys adjudged or decreed
to be payable.

     In case there shall be pending proceedings relative to the Company or any
other obligor upon the securities under Title 11 of the United States Code or
any other applicable federal or state bankruptcy, insolvency or other similar
law, or in case a receiver, assignee or trustee in bankruptcy or reorganization,
liquidator, sequestrator or similar official shall have been appointed for or
taken possession of the Company or its property or such other obligor, or in
case of any other comparable judicial proceedings relative to the Company or
other obligor under the Convertible Debentures, or to the property of the
Company or such other obligor, the Trustee, irrespective of whether the
principal of any Convertible Debentures shall then be due and payable as therein
expressed or by declaration or otherwise and irrespective of whether the Trustee
shall have made any demand pursuant to the 

                                       34
<PAGE>
 
provisions of this Section, shall be entitled and empowered, by intervention in
such proceeding or otherwise:

          (a)  to file and prove a claim or claims for the whole amount of
     principal and interest owing and unpaid in respect of the Convertible
     Debentures, and to file such other papers or documents as may be necessary
     or advisable in order to have the claims of the Trustee (including any
     claim for reasonable compensation to, and all expenses and liabilities
     incurred and all advances with interest made by, the Trustee and each
     predecessor Trustee, and their respective agents, attorneys and counsel,
     except as a result of negligence or bad faith) and of the Holders of
     Convertible Debentures allowed in any judicial proceedings relative to the
     Company or other obligor upon all Convertible Debentures, or to the
     property of the Company or such obligor, and

          (b)  to collect and receive any moneys or other property payable or
     deliver able on any such claims, and to distribute all amounts received
     with respect to the claims of the Holders of Convertible Debentures and of
     the Trustee on their behalf; and any trustee, receiver, liquidator,
     custodian or other similar official is hereby authorized by each of the
     Holders of Convertible Debentures to make payments to the Trustee for the
     Convertible Debentures, and, in the event that such Trustee shall consent
     to the making of payments directly to the Holders of Convertible
     Debentures, to pay to such Trustee such amounts as shall be sufficient to
     cover reasonable compensation to, and all expenses and liabilities incurred
     and all advances with interest made by, such Trustee, each predecessor
     Trustee and their respective agents, attorneys and counsel and all other
     amounts due to such Trustee or any predecessor Trustee pursuant to Section
     6.7, except as a result of Trustee's negligence or bad faith.

     Nothing herein contained shall be deemed to authorize the Trustee to
authorize or consent to or accept or adopt on behalf of any Holder of
Convertible Debentures any plan of reorganization, arrangement, adjustment or
composition affecting the Convertible Debentures or the rights of any Holder
thereof, or to authorize the Trustee to vote in respect of the claim of any
Holder of Convertible Debentures in any such proceeding.

     All rights of action and of asserting claims under this Indenture, or under
any of the Convertible Debentures, may be enforced by the Trustee for the
Convertible Debentures without the possession of any of the Convertible
Debentures or the production thereof at any trial or other proceedings relative
thereto, any such action or proceedings instituted by the Trustee shall be
brought in its own name as trustee of an express trust, and any recovery of
judgment, subject to the payment of the expenses, disbursements and compensation
of the Trustee, each predecessor Trustee and their respective agents and
attorneys, shall be for the ratable benefit of the Holders of the Convertible
Debentures in respect of which such action was taken.

     In any proceedings brought by the Trustee for the Convertible Debentures
(and also any proceedings involving the interpretation of any provision of this
Indenture to which the 

                                       35
<PAGE>
 
Trustee shall be a party), the Trustee shall be held to represent all the
Holders of the Convertible Debentures in respect to which such action was taken,
and it shall not be necessary to make any Holders of such Convertible Debentures
parties to any such proceedings.

     Section 5.3  Application of Proceeds.  Any moneys collected by the Trustee
for the Convertible Debentures pursuant to this Article in respect of the
Convertible Debentures shall be applied in the following order at the date or
dates fixed by such Trustee and, in case of the distribution of such moneys on
account of principal or interest, upon presentation of the several Convertible
Debentures in respect of which moneys have been collected and stamping (or
otherwise noting) thereon the payment, or issuing Convertible Debentures in
reduced principal amounts in exchange for the presented Convertible Debentures
if only partially paid, or upon surrender thereof if fully paid:

          FIRST:  To the payment of costs and expenses applicable in respect of
     which moneys have been collected, including reasonable compensation to, and
     all expenses and liabilities incurred and all advances with interest made
     by, the Trustee and each predecessor Trustee and their respective agents
     and attorneys and all other amounts due to the Trustee or any predecessor
     Trustee pursuant to Section 6.7, except as a result of Trustee's negligence
     or bad faith;

          SECOND:  To the payment of the amounts then due and unpaid for
     interest on the Convertible Debentures for which principal is not yet due
     and payable in respect of which moneys have been collected, such payments
     to be made ratably to the persons entitled thereto, without discrimination
     or preference, according to the amounts then due and payable on such
     Convertible Debentures for interest;

          THIRD:  To the payment of the amounts then due and unpaid for
     principal of and interest on the Convertible Debentures for which principal
     is due and payable in respect of which moneys have been collected, such
     payments to be made ratably to the persons entitled thereto, without
     discrimination or preference, according to the amounts then due and payable
     on such Convertible Debentures of principal and interest, respectively; and

          FOURTH:  To the payment of the remainder, if any, to the Company or
     any other Person lawfully entitled thereto.

     Section 5.4  Restoration of Rights on Abandonment of Proceedings.  In case
the Trustee for the Convertible Debentures or any Holder shall have proceeded to
enforce any right under this Indenture and such proceedings shall have been
discontinued or abandoned for any reason, or shall have been determined
adversely to the Trustee or to such Holder, then and in every such case, subject
to the determination in any such proceeding, the Company, the Trustee and the
Holders shall be restored respectively to their former positions and rights
hereunder, and all rights, remedies and powers of the Company, the Trustee and
the Holders of Convertible Debentures shall continue as though no such
proceedings had been taken.

                                       36
<PAGE>
 
     Section 5.5  Limitations on Suits by Holders of Convertible Debentures.  No
Holder of any Convertible Debenture shall have any right by virtue or by
availing of any provision of this Indenture to institute any action or
proceeding at law or in equity or in bankruptcy or otherwise upon or under with
respect to this Indenture, or for the appointment of a trustee, receiver,
liquidator, custodian or other similar official or for any other remedy
hereunder, unless such Holder previously shall have given to the Trustee written
notice of any Event of Default and of the continuance thereof, as hereinbefore
provided, and unless also the Holders of not less than 25% in aggregate
principal amount of the Convertible Debentures then Outstanding shall have made
written request upon the Trustee to institute such action or proceedings in its
own name as trustee hereunder and shall have offered to the Trustee such
reasonable indemnity, as it may require, against the costs, expenses and
liabilities to be incurred therein or thereby and the Trustee for 60 days after
its receipt of such notice, request and offer of indemnity shall have failed to
institute any such action or proceeding and no direction inconsistent with such
written request shall have been given to the Trustee during such 60 day period
by Holders of a majority in principal amount of the Convertible Debentures then
Outstanding; it being understood and intended, and being expressly covenanted by
the taker and Holder of every Convertible Debenture with every other taker and
Holder of a Convertible Debenture and the Trustee, that no one or more Holders
of Convertible Debentures shall have any right in any manner whatever, by virtue
or by availing of any provision of this Indenture to affect, disturb or
prejudice the rights of any other such Holder of Convertible Debentures, or to
obtain or seek to obtain priority over or preference to any other such Holder or
to enforce any right under this Indenture, except in the manner herein provided
and for the equal, ratable and common benefit of all Holders of Convertible
Debentures.

     Section 5.6  Unconditional Right of Holders of Convertible Debentures to
Institute Certain Suits.  Notwithstanding any provision in this Indenture and
any provision of any Convertible Debenture, the right of any Holder of any
Convertible Debenture to receive payment of the principal of and (subject to
Section 2.9 and Article XI) interest on such Convertible Debenture at the
respective rates, in the respective amount on or after the respective due dates
expressed in such Convertible Debenture, and to institute suit for the
enforcement of any such payment on or after such respective dates, shall not be
impaired or affected without the consent of such Holder.

     Section 5.7  Powers and Remedies Cumulative; Delay or Omission Not Waiver
of Default.  Except as provided in Section 2.11 and Section 5.5, no right or
remedy herein conferred upon or reserved to the Trustee or to the Holders of
Convertible Debentures is intended to be exclusive of any other right or remedy,
and every right and remedy shall, to the extent permitted by law, be cumulative
and in addition to every other right and remedy given hereunder or now or
hereafter existing at law or in equity or otherwise.  The assertion or
employment of any right or remedy hereunder, or otherwise, shall not prevent the
concurrent assertion or employment of any other appropriate right or remedy.

     No delay or omission of the Trustee or of any Holder of Convertible
Debentures to exercise any right or power accruing upon any Event of Default
occurring and continuing as aforesaid shall impair any such right or power or
shall be construed to be a waiver of any

                                       37
<PAGE>
 
such Event of Default or an acquiescence therein; and, subject to Section 5.5,
every power and remedy given by this Indenture or by law to the Trustee or to
the Holders of Convertible Debentures may be exercised from time to time, and as
often as shall be deemed expedient, by the Trustee or the Holders of Convertible
Debentures.

     Section 5.8  Control by Holders of Convertible Debentures.  The Holders of
a majority in aggregate principal amount of the Convertible Debentures at the
time Outstanding shall have the right to direct the time, method and place of
conducting any proceeding for any remedy available to the Trustee, or exercising
any trust or power conferred on the Trustee with respect to the Convertible
Debentures by this Indenture; provided that such direction shall not be in
conflict with any rule of law or the provisions of this Indenture; and provided
further that the Trustee, being advised by counsel, shall have the right to
decline to follow any such direction if the Trustee shall determine that the
action or proceedings so directed would involve the Trustee in personal
liability or if the Trustee in good faith shall so determine that the actions or
forbearance specified in or pursuant to such direction would be unduly
prejudicial to the interest of Holders of the Convertible Debentures not joining
in the giving of said direction.

     Section 5.9  Waiver of Past Defaults.  The Holders of not less than a
majority in aggregate principal amount of the Convertible Debentures at the time
Outstanding may on behalf of the Holders of all the Convertible Debentures waive
any past default hereunder or its consequences, except a default:

          (a)  in the payment of the principal of (or premium, if any) or any
     interest on any Convertible Debenture as and when the same shall become due
     by the terms of Convertible Debentures otherwise than by acceleration
     (unless such default has been cured and sums sufficient to pay all matured
     installments of interest and principal and any premium has been deposited
     with the Trustee (in accordance with Section 5.1)), or

          (b)  in respect of a covenant or provision hereof which under Article
     VIII cannot be modified or amended without the consent of the Holder of
     each Outstanding Convertible Debenture affected;

provided, however, that if the Convertible Debentures are held by the McKesson
Trust or the Institutional Trustee of such Trust, such waiver or modification to
such waiver shall not be effective until the holders of a majority in aggregate
liquidation amount of Trust Securities of the McKesson Trust shall have
consented to such waiver or modification to such waiver; provided further, that
if the consent of the Holder of each Outstanding Convertible Debenture is
required, such waiver shall not be effective until each holder of the Trust
Securities of the McKesson Trust shall have consented to such waiver.

     Upon any such waiver, such default shall cease to exist and be deemed to
have been cured and not to have occurred, and any Event of Default arising
therefrom shall be deemed to have been cured and not to have occurred for every
purpose of this Indenture; but no such

                                       38
<PAGE>
 
waiver shall extend to any subsequent or other default or Event of Default or
impair any right consequent thereon.

     Section 5.10  Right of Court to Require Filing of Undertaking to Pay Costs.
All parties to this Indenture agree, and each Holder of any Convertible
Debenture, by his acceptance thereof, shall be deemed to have agreed, that any
court may in its discretion require, in any suit for the enforcement of any
right or remedy under this Indenture or in any suit against the Trustee for any
action taken, suffered or omitted by it as Trustee, the filing by any party
litigant in such suit of an undertaking to pay the costs of such suit, and that
such court may in its discretion assess reasonable costs, including reasonable
attorneys' fees and expenses, against any party litigant in such suit, having
due regard to the merits and good faith of the claims or defenses made by such
party litigant; but the provisions of this Section shall not apply to any suit
instituted by the Trustee, to any suit instituted by any Holder of Convertible
Debentures or group of Holders of Convertible Debentures holding in the
aggregate more than 10% in principal amount of the Outstanding Convertible
Debentures, or to any suit instituted by a Holder of Convertible Debentures for
the enforcement of the payment of the principal of or interest on any
Convertible Debenture on or after the due date expressed in such Convertible
Debenture or any date fixed for redemption.

     Section 5.11  Suits for Enforcement.  In case an Event of Default has
occurred, has not been waived and is continuing, the Trustee may in its
discretion proceed to protect and enforce the rights vested in it by this
Indenture by such appropriate judicial proceedings as the Trustee shall deem
most effectual to protect and enforce any of such rights, either at law or in
equity or in bankruptcy or otherwise, whether for the specific enforcement of
any covenant or agreement contained in this Indenture or in aid of the exercise
of any power granted in this Indenture or to enforce any other legal or
equitable right vested in the Trustee by this Indenture or by law.


                                  ARTICLE VI

                            CONCERNING THE TRUSTEE

     Section 6.1  Duties of the Trustee.

     (a)  If an Event of Default has occurred and is continuing with respect to
the Convertible Debentures, the Trustee shall exercise the rights and powers
vested in it by this Indenture and use the same degree of care and skill in its
exercise as a prudent person would exercise or use under the circumstances in
the conduct of his or her own affairs.

     (b)  Except during the continuance of an Event of Default with respect to
the Convertible Debentures:

          (i)  the Trustee need perform only those duties that are specifically 
     set forth in this Indenture and no others; and
                                       39
<PAGE>
 

          (ii)   in the absence of bad faith on its part, the Trustee may
     conclusively rely, as to the truth of the statements and the correctness of
     the opinions expressed therein, upon certificates or opinions furnished to
     the Trustee and conforming on their face to the requirements of this
     Indenture.  However, in the case of any such certificates or opinions which
     by any provision hereof are specifically required to be furnished to the
     Trustee, the Trustee shall examine the certificates and opinions to
     determine whether or not they conform on their face to the requirements of
     this Indenture.

     (c)  The Trustee may not be relieved from liability for its own negligent
failure to act or its own willful misconduct, except that:

          (i)    this paragraph (c) does not limit the effect of paragraph (b)
     of this Section 6.1;

          (ii)   the Trustee shall not be liable for any error of judgment made
     in good faith by a Responsible Officer unless it is proved that the Trustee
     was negligent in ascertaining the pertinent facts; and

          (iii)  the Trustee shall not be liable with respect to any action it
     takes or omits to take in good faith in accordance with a direction
     received by it pursuant to Section 5.8.

     (d)  Every provision of this Indenture that in any way relates to the
Trustee is subject to paragraphs (a), (b), (c) and (e) of this Section 6.1.

     (e)  The Trustee may refuse to perform any duty or exercise any right or
power or extend or risk its own funds or otherwise incur any financial liability
unless it receives indemnity satisfactory to it against any loss, liability or
expense.

     (f)  Money held by the Trustee in trust hereunder need not be segregated
from other funds except to the extent required by law.  The Trustee shall be
under no liability for interest on any money received by it hereunder except as
otherwise agreed in writing with the Company.

     Section 6.2  Rights of Trustee.  Subject to Section 6.1 and the provisions
of the Trust Indenture Act:

     (a)  The Trustee may rely on any document believed by it to be genuine and
to have been signed or presented by the proper person.  The Trustee need not
investigate any fact or matter stated in the document.

     (b)  Before the Trustee acts or refrains from acting, it may require an
Officers' Certificate or an Opinion of Counsel.  The Trustee shall not be liable
for any action it takes or omits to take in good faith in reliance on such
Officers' Certificate or Opinion of Counsel.

                                       40
<PAGE>
 
     (c)  Subject to the provisions of Section 6.1(c), the Trustee shall not be
liable for any action it takes or omits to take in good faith which it believes
to be authorized or within its rights or powers.

     (d)  The Trustee may consult with counsel of its selection and the advice
of such counsel or any Opinion of Counsel shall be full and complete
authorization and protection in respect of any action taken, suffered or omitted
by it hereunder in good faith and in reliance thereon in accordance with such
advice or Opinion of Counsel.

     (e)  The Trustee shall be under no obligation to exercise any of the rights
or powers vested in it by this Indenture at the request or direction of any of
the Holders pursuant to this Indenture, unless such Holders shall have offered
to the Trustee reasonable security or indemnity against the costs, expenses and
liabilities which might be incurred by it in compliance with such request or
direction.

     (f)  The Trustee may execute any of the trusts or powers hereunder or
perform any duties hereunder either directly or by or through agents or
attorneys and the Trustee shall not be responsible for any misconduct or
negligence on the part of any agent or attorney appointed with due care by it
hereunder.

     Section 6.3  Individual Rights of Trustee.  The Trustee in its individual
or any other capacity may become the owner or pledgee of Convertible Debentures
and may otherwise deal with the Company or its affiliates with the same rights
it would have if it were not Trustee.  Any Paying Agent, Registrar or co-
Registrar may do the same with like rights.  However, the Trustee must comply
with Sections 6.10 and 6.11.

     Section 6.4  Trustee's Disclaimer.  The Trustee makes no representation as
to the validity or adequacy of this Indenture or the Convertible Debentures, it
shall not be accountable for the Company's use of the proceeds from the
Convertible Debentures, it shall not be responsible for any statement in the
registration statement for the Convertible Debentures under the Securities Act
or in the Indenture or the Convertible Debentures (other than its certificate of
authentication).

     Section 6.5  Notice of Defaults.  If a default occurs and is continuing
with respect to any Convertible Debentures and if it is known to the Trustee
through oral or written notice to a Responsible Officer, the Trustee shall give
to each Holder of Convertible Debentures notice of the default within 90 days
after such default occurs.  Except in the case of a default described in Section
5.1(a) or (b), the Trustee may withhold the notice if and so long as a committee
of its Responsible Officers in good faith determines that withholding the notice
is in the interest of Holders of Convertible Debentures.

     Section 6.6  Reports by Trustee to Holders.  Within 60 days after each May
15 beginning with the May 15 following the date of this Indenture, the Trustee
shall mail to each Holder of Convertible Debentures and each other person
specified in TIA Section 313(c) a brief report dated as of such May 15 that
complies with TIA Section 313(a) to the extent required thereby.  The Trustee
also shall comply with TIA Section 313(b).

                                       41
<PAGE>
 
     A copy of each report at the time of its mailing to Holders of Convertible
Debentures shall be filed with the Commission and each securities exchange on
which the Convertible Debentures are listed.  The Company agrees promptly to
notify the Trustee whenever the Convertible Debentures become listed on any
securities exchange and of any delisting thereof.

     Section 6.7  Compensation and Indemnity.  The Company agrees:

          (a)  to pay to the Trustee from time to time in Dollars such
     compensation as shall be agreed to in writing between the Company and the
     Trustee for all services rendered by it hereunder (which compensation shall
     not be limited by any provision of law in regard to the compensation of a
     trustee of an express trust);

          (b)  to reimburse the Trustee upon its request for all reasonable
     expenses, disbursements and advances with interest thereon incurred or made
     by the Trustee in accordance with any provision of this Indenture
     (including the reasonable compensation and the expenses, advances with
     interest thereon and disbursements of its agents and counsel), except to
     the extent any such expense, disbursement or advance may be attributable to
     its negligence or bad faith; and

          (c)  to indemnify the Trustee in Dollars for, and to hold it harmless
     against, any loss, liability or expense arising out of or in connection
     with the acceptance or administration of this trust or the performance of
     its duties hereunder, including the costs and expenses of defending itself
     against any claim or liability in connection with the exercise or
     performance of any of its powers or duties hereunder (including the
     reasonable compensation and the expenses, advances with interest thereon
     and disbursements of its agents and counsel), except to the extent that any
     such loss, liability or expense may be attributable to its negligence or
     bad faith.

     As security for the performance of the obligations of the Company in this
Section 6.7, the Trustee shall have a lien prior to the Convertible Debentures
on all money or property held or collected by the Trustee, except that held in
trust to pay the principal of or interest, if any, on particular Convertible
Debentures.

     "Trustee" for purposes of this Section 6.7 includes any predecessor
Trustee, provided that the negligence or bad faith of any Trustee shall not be
attributable to any other Trustee.

     The Company's payment obligations pursuant to this Section 6.7 shall
survive the discharge of this Indenture.  When the Trustee incurs expenses after
the occurrence of a default specified in Sections 5.1(d) and 5.1(e), such
expenses are intended to constitute expenses of administration under bankruptcy
law.

     Section 6.8  Replacement of Trustee.  The Trustee may resign at any time
with respect to Convertible Debentures by so notifying the Company; provided,
however, no such resignation shall be effective until a successor Trustee has
accepted its appointment pursuant to this Section 6.8.  The Holders of a
majority in aggregate principal amount of the

                                       42
<PAGE>
 
Outstanding Convertible Debentures may remove the Trustee at the time
outstanding by so notifying the Trustee and the Company. The Company shall
remove the Trustee if:

          (1)  the Trustee fails to comply with Section 6.10;

          (2)  the Trustee is adjudged bankrupt or insolvent;

          (3)  a receiver or public officer takes charge of the Trustee or its
     property; or

          (4)  the Trustee otherwise becomes incapable of acting.

     If the Trustee resigns or is removed or if a vacancy exists in the office
of Trustee for any reason, with respect to the Convertible Debentures, the
Company shall promptly appoint, by resolution of its Board of Directors, a
successor Trustee with respect to the Convertible Debentures.

     A successor Trustee shall deliver a written acceptance of its appointment
to the retiring Trustee and to the Company.  Thereupon the resignation or
removal of the retiring Trustee shall become effective, and the successor
Trustee shall have all the rights, powers and duties of the Trustee under this
Indenture with respect to the Convertible Debentures.  The successor Trustee
shall mail a notice of its succession to Holders of Convertible Debentures so
affected.  The retiring Trustee shall promptly transfer all property held by it
as Trustee to the successor Trustee, subject to the lien provided for in Section
6.7.

     If a successor Trustee does not take office within 30 days after the
retiring Trustee resigns or is removed, the retiring Trustee, the Company or the
Holders of a majority in aggregate principal amount of the Convertible
Debentures at the time Outstanding may petition any court of competent
jurisdiction for the appointment of a successor Trustee.

     If the Trustee fails to comply with Section 6.10, any Holder of Convertible
Debentures may petition any court of competent jurisdiction for the removal of
the Trustee and the appointment of a successor Trustee.

     Section 6.9  Successor Trustee by Merger.  If the Trustee consolidates
with, merges or converts into, or transfers all or substantially all its
corporate trust business or assets to, another corporation, the resulting,
surviving or transferee corporation without any further act shall be the
successor Trustee.

     Section 6.10  Eligibility; Disqualification.  The Trustee shall at all
times satisfy the requirements of TIA Section 310(a)(1) and Section 310(a)(5).
The Trustee shall have combined capital and surplus of at least $50,000,000 as
set forth in its most recent published annual report of condition.  The Trustee
shall comply with TIA Section 310(b).

     Section 6.11  Preferential Collection of Claims Against Company.  The
Trustee shall comply with TIA Section 311(a), excluding any creditor
relationship listed in TIA Section 

                                       43
<PAGE>
 
311(b). A Trustee who has resigned or been removed shall be subject to TIA
Section 311(a) to the extent indicated therein.


                                  ARTICLE VII

               CONCERNING THE HOLDERS OF CONVERTIBLE DEBENTURES

     Section 7.1  Evidence of Action Taken by Holders of Convertible Debentures.

     (a)  Any request, demand, authorization, direction, notice, consent, waiver
or other action provided in this Indenture to be given or taken by a specified
percentage in principal amount of the Holders of Convertible Debentures may be
embodied in and evidenced by one or more instruments or substantially similar
tenor signed by such specified percentage of Holders of Convertible Debentures
in person or by agent duly appointed in writing; and, except as herein otherwise
expressly provided, such action shall become effective when such instrument or
instruments are delivered to the Trustee.  Proof of execution of any instrument
or of a writing appointing any such agent shall be sufficient for any purpose of
this Indenture and (subject to Sections 6.1 and 6.2) conclusive in favor of the
Trustee and the Company, if made in the manner provided in this Article.

     (b)  The ownership of such Convertible Debentures shall be provided by the
Security Register.

     Section 7.2  Proof of Execution of Instruments.  Subject to Sections 6.1
and 6.2, the execution of any instrument by a Holder of Convertible Debentures
or his agent or proxy may be proved in accordance with such reasonable rules and
regulations as may be prescribed by the Trustee or in such manner as shall be
satisfactory to the Trustee.

     Section 7.3  Holders to be Treated as Owners.  The Company, the Trustee and
any agent of the Company or the Trustee may deem and treat the person in whose
name any Convertible Debenture shall be registered upon the Security Register as
the absolute owner of such Convertible Debenture (whether or not such
Convertible Debenture shall be overdue and notwithstanding any notification of
ownership or other writing thereon) for the purpose of receiving payment of or
on account of the principal of and (subject to Section 2.9) interest on such
Convertible Debenture and for all other purposes; and neither the Company nor
the Trustee nor any agent of the Company or the Trustee shall be affected by any
notice to the contrary.

     Section 7.4  Convertible Debentures Owned by Company Deemed Not
Outstanding.  In determining whether the Holders of the requisite aggregate
principal amount of Outstanding Convertible Debentures have concurred in any
direction, consent or waiver under this Indenture, Convertible Debentures which
are owned by the Company or any other obligor on the Convertible Debentures with
respect to which such determination is being made or by any person directly or
indirectly controlling or controlled by or under direct or indirect common
control with the Company or any other obligor on the Convertible 

                                       44
<PAGE>
 
Debentures with respect to which such determination is being made shall be
disregarded and deemed not to be Outstanding for the purpose of any such
determination, except that for the purpose of determining whether the Trustee
shall be protected in relying on any such direction, consent or waiver only
Convertible Debentures which the Trustee knows are so owned shall be so
disregarded. Convertible Debentures so owned which have been pledged in good
faith may be regarded as Outstanding if the pledgee establishes to the
satisfaction of the Trustee the pledgee's right so to act with respect to such
Convertible Debentures and that the pledgee is not the Company or any other
obligor upon the Convertible Debentures or any person directly or indirectly
controlling or controlled by or under direct or indirect common control with the
Company or any other obligor on the Convertible Debentures.

     Section 7.5  Right of Revocation of Action Taken.  At any time prior to
(but not after) the evidencing to the Trustee, as provided in Section 7.1, of
the taking of any action by the Holders of the percentage in aggregate principal
amount of the Convertible Debentures, as the case may be, specified in this
Indenture in connection with such action, any Holder of a Convertible Debenture
the serial number of which is shown by the evidence to be included among the
serial numbers of the Convertible Debentures the Holders of which have consented
to such action may, by filing written notice at the Corporate Trust Office and
upon proof of holding as provided in this Article, revoke such action so far as
concerns such Convertible Debenture.  Except as aforesaid any such action taken
by the Holder of any Convertible Debentures shall be conclusive and binding upon
such Holder and upon all future Holders and owners of such Convertible Debenture
and of any Convertible Debentures issued in exchange or substitution therefor,
irrespective of whether or not any notation in regard thereto is made upon any
such Convertible Debenture.  Any action taken by the Holders of the percentage
in aggregate principal amount of the Convertible Debentures, as the case may be,
specified in this Indenture in connection with such action shall be conclusively
binding upon the Company, the Trustee and the Holders of all the Convertible
Debentures affected by such action.


                                 ARTICLE VIII

                            SUPPLEMENTAL INDENTURES

     Section 8.1  Supplemental Indentures Without Consent of Holders of
Convertible Debentures.  The Company, when authorized by a resolution of its
Board of Directors, and the Trustee for the Convertible Debentures may from time
to time and at any time enter into an indenture or indentures supplemental
hereto (which shall conform to the provisions of the Trust Indenture Act as in
force at the date of the execution thereof), in form satisfactory to such
Trustee, for one or more of the following purposes:

          (a)  to convey, transfer, assign, mortgage or pledge to the Trustee as
     security for the Convertible Debentures any property or assets;

                                       45
<PAGE>
 
          (b)  to evidence the succession of another corporation to the Company,
     or successive successions, and the assumption by the successor corporation
     of the covenants, agreements and obligations of the Company pursuant to
     Article IX;

          (c)  to add to the covenants of the Company such further covenants,
     restrictions, conditions or provisions for the protection of the Holders of
     Convertible Debentures;

          (d)  to cure any ambiguity or to correct or supplement any provision
     contained herein or in any supplemental indenture which may be defective or
     inconsistent with any other provision contained herein or in any
     supplemental indenture; or to make such other provisions in regard to
     matters or questions arising under this Indenture or under any supplemental
     indenture as the Board of Directors may deem necessary or desirable and
     which shall not materially and adversely affect the interests of the
     Holders of the Convertible Debentures; or

          (e)  to evidence and provide for the acceptance of appointment
     hereunder by a successor Trustee with respect to the Convertible
     Debentures.

     The Trustee is hereby authorized to join with the Company in the execution
of any such supplemental indenture, to make any further appropriate agreements
and stipulations which may be therein contained and to accept the conveyance,
transfer, assignment, mortgage or pledge of any property thereunder, but the
Trustee shall not be obligated to enter into any such supplemental indenture
which affects the Trustee's own rights, duties or immunities under this
Indenture or otherwise.

     Any supplemental indenture authorized by the provisions of this Section may
be executed without the consent of the Holders of any of the Convertible
Debentures at the time Outstanding, notwithstanding any of the provisions of
Section 8.2.

     Section 8.2  Supplemental Indentures With Consent of Holders of Convertible
Debentures.  With the consent (evidenced as provided in Article VII) of the
Holders of not less than a majority in aggregate principal amount of the
Convertible Debentures at the time Outstanding (voting as one class), the
Company, when authorized by a resolution of its Board of Directors, and the
Trustee may, from time to time and at any time, enter into an indenture or
indentures supplemental hereto (which shall conform to the provisions of the
Trust Indenture Act as in force at the date of execution thereof) for the
purpose of adding any provisions to or changing in any manner or eliminating any
of the provisions of this Indenture or of any supplemental indenture or of
modifying in any manner the rights of the Holders of the Convertible Debentures;
provided, however, that no such supplemental indenture shall (a) except to the
extent permitted by Article XI, extend the Stated Maturity of any Convertible
Debenture, or reduce the principal amount thereof or any premium thereon, or
reduce the rate or extend the time of payment of interest thereon, or reduce any
amount payable on redemption thereof, or make the principal thereof or interest
thereon payable in any coin or currency other than that provided in the
Convertible Debentures or in accordance with the terms thereof, or impair or
affect the right of any Holder of Convertible Debentures 

                                       46
<PAGE>
 
to institute suit for payment thereof, or adversely affect the right to convert
Convertible Debentures, or modify the subordination provisions of this Indenture
in any manner adverse to the Holders of Convertible Debentures without the
consent of the Holders of each Convertible Debenture so affected, or (b) reduce
the aforesaid percentage of Convertible Debentures, the consent of the Holders
of which is required for any such supplemental indenture, without the consent of
the Holders of each Convertible Debenture so affected.

     Upon the request of the Company, accompanied by a copy of a resolution of
the Board of Directors certified by the secretary or assistant secretary of the
Company authorizing the execution of any such supplemental indenture, and upon
the filing with the Trustee of evidence of the consent of Holders of Convertible
Debentures as aforesaid and other documents, if any, required by Section 7.1,
the Trustee shall join with the Company in the execution of such supplemental
indenture or otherwise, in which case such Trustee may in its discretion, but
shall not be obligated to, enter into such supplemental indenture which affects
the Trustee's own rights, duties or immunities under this Indenture or
otherwise.

     It shall not be necessary for the consent of the Holders of Convertible
Debentures under this Section to approve the particular form of any proposed
supplemental indenture, but it shall be sufficient if such consent shall approve
the substance thereof.

     Promptly after the execution by the Company and the Trustee of any
supplemental indenture pursuant to the provisions of this Section, the Company
shall give notice thereof to the Holders of then Outstanding Convertible
Debentures, by mailing a notice thereof by first-class mail to such Holders at
their addresses as they shall appear on the Security Register, and in each case
such notice shall set forth in general terms the substance of such supplemental
indenture.  Any failure of the Company to give such notice, or any defect
therein, shall not, however, in any way impair or affect the validity of any
such supplemental indenture.

     Section 8.3  Effect of Supplemental Indenture.  Every supplemental
indenture executed pursuant to this Article VIII shall conform to the
requirements of the Trust Indenture Act.  Upon the execution of any supplemental
indenture pursuant to the provisions hereof, this Indenture shall be and be
deemed to be modified and amended in accordance therewith and the respective
rights, limitations of rights, obligations, duties and immunities under this
Indenture of the Trustee, the Company and the Holders of Convertible Debentures
shall thereafter be determined, exercised and enforced hereunder subject in all
respects to such modifications and amendments, and all the terms and conditions
of any such supplemental indenture shall be and be deemed to be a part of the
terms and conditions of this Indenture for any and all purposes.

     Section 8.4  Documents to Be Given to Trustee.  The Trustee, subject to the
provisions of Section 6.1 and 6.2, shall receive an Officers' Certificate and an
Opinion of Counsel as conclusive evidence that any supplemental indenture
executed pursuant to this Article VIII complies with the applicable provisions
of this Indenture.

                                       47
<PAGE>
 
     Section 8.5 Notation on Convertible Debentures in Respect of Supplemental
Indentures. Convertible Debentures authenticated and delivered after the
execution of any supplemental indenture pursuant to the provisions of this
Article VIII may bear, upon the direction of the Company, a notation in form
satisfactory to the Trustee for the Convertible Debentures as to any matter
provided for by such supplemental indenture. If the Company or the Trustee shall
so determine, new Convertible Debentures so modified as to conform, in the
opinion of the Trustee and the Company, to any modification of this Indenture
contained in any such supplemental indenture may be prepared by the Company,
authenticated by the Trustee and delivered in exchange for the Convertible
Debentures then Outstanding.


                                  ARTICLE IX

                   CONSOLIDATION, MERGER, SALE OR CONVEYANCE

     Section 9.1  Company May Consolidate, etc., on Certain Terms.  The Company
may sell, transfer, lease or otherwise convey all or substantially all of its
assets on a consolidated basis to any Person, or consolidate or merge with or
into, any other Person, provided that in any such case, (a) either (i) the
Company shall be the continuing corporation, or (ii) if the Company is not the
continuing corporation, the successor corporation or Person which acquires by
sale, transfer, lease or other conveyance all or substantially all of the assets
of the Company, shall be a corporation organized and validly existing under the
laws of the United States of America or any state thereof or the District of
Columbia and shall expressly assume the due and punctual payment of the
principal of, premium, if any, and interest (including Additional Sums and
Compound Interest) on all of the Convertible Debentures according to their
tenor, and the due and punctual performance and observance of all of the
covenants, agreements and conditions (A) of this Indenture to be performed or
observed by the Company by supplemental indenture satisfactory to the Trustee,
executed and delivered to the Trustee by such corporation or entity, and (B) of
the Registration Rights Agreements, by amendment thereto, (b) immediately after
such merger or consolidation, or such sale, transfer, lease or other conveyance,
no Event of Default, and no event which, after notice or lapse of time or both,
would become an Event of Default, shall have occurred and be continuing, and (c)
the Company has delivered to the Trustee an Officers' Certificate and an Opinion
of Counsel, each stating that the requirements of this Section have been
complied with.

     Section 9.2  Successor Corporation Substituted.  In case of any such
consolidation, merger, sale, transfer, lease or conveyance, and following such
an assumption by the successor corporation, such successor corporation shall
succeed to and be substituted for the Company, with the same effect as if it had
been named herein, and the Company shall be discharged from all obligations and
covenants under this Indenture, the Convertible Debentures and the Registration
Rights Agreements and may be liquidated and dissolved.  Such successor
corporation may cause to be signed, and may issue either in its own name or in
the name of the Company any or all of the Convertible Debentures issuable
hereunder which theretofore shall not have been signed by the Company and be
delivered to the Trustee; and, upon the order of such successor corporation
instead of the Company and 

                                       48
<PAGE>
 
subject to all the terms, conditions and limitations in this Indenture
prescribed, the Trustee shall authenticate and shall make available for delivery
any Convertible Debentures which previously shall have been signed and delivered
by the officers of the Company to the Trustee for authentication, and any
Convertible Debentures, which such successor corporation thereafter shall cause
to be signed and delivered to the Trustee for that purpose. All of the
Convertible Debentures so issued shall in all respects have the same legal rank
and benefit under this Indenture as the Convertible Debentures theretofore or
thereafter issued in accordance with the terms of this Indenture as though all
of such Convertible Debentures had been issued at the date of the execution
hereof.

     In case of any such consolidation, merger, sale, transfer, lease or
conveyance such changes in phraseology and form (but not in substance) may be
made in the Convertible Debentures thereafter to be issued as may be
appropriate.

     Section 9.3  Opinion of Counsel to Trustee.  The Trustee, subject to the
provisions of Section 6.1 and 6.2, may receive an Opinion of Counsel, prepared
in accordance with Section 15.5, as conclusive evidence that any such
consolidation, merger, sale, lease or conveyance, and any such assumption, and
any such liquidation or dissolution, complies with the applicable provisions of
this Indenture.


                                   ARTICLE X

                   REDEMPTION OF THE CONVERTIBLE DEBENTURES

     Section 10.1  Tax Event Redemption.  If a Tax Event (as defined in the
Declaration) has occurred and is continuing and:

          (a)  the Company has received a Redemption Tax Opinion (as defined in
     the Declaration); or

          (b)  after receiving a Dissolution Tax Opinion (as defined in the
     Declaration), the Regular Trustees shall have been informed by tax counsel
     rendering the Dissolution Tax Opinion that a No-Recognition Opinion (as
     defined in the Declaration) cannot be delivered to the Trust,

then, notwithstanding Section 10.2(a) but subject to Section 10.2(b), the
Company shall have the right upon not less than 30 days nor more than 60 days
notice to the Holders of the Convertible Debentures to redeem the Convertible
Debentures, in whole or in part, for cash within 90 days following the
occurrence of such Tax Event (the "90-Day Period") at a redemption price equal
to 100% of the principal amount to be redeemed plus any accrued and unpaid
interest thereon to the date of such redemption (the "Redemption Price"),
provided that if at the time there is available to the Company or the Trust the
opportunity to eliminate, within the 90-Day Period, the Tax Event by taking some
ministerial action ("Ministerial Action"), such as filing a form or making an
election, or pursuing some other similar reasonable measure which has no adverse
effect on the Company, the Trust or the 

                                       49
<PAGE>
 
Holders of the Trust Securities issued by the Trust, the Company shall pursue
such Ministerial Action in lieu of redemption. The Redemption Price shall be
paid prior to 12:00 noon, New York time, on the date of such redemption or such
earlier time as the Company determines, provided that the Company shall deposit
with the Trustee an amount sufficient to pay the Redemption Price prior to the
redemption date.


     Section 10.2  Optional Redemption by Company.

     (a)  Subject to the provisions of Section 10.2(b) and to the provisions of
this Article X generally, except as otherwise may be specified in Section 10.1
or elsewhere in this Indenture, the Company shall have the right to redeem the
Convertible Debentures, in whole or in part, from time to time, on or after
March 4, 2000.  Any redemption pursuant to this paragraph will be made upon not
less than 30 days nor more than 60 days notice to the Holders of the Convertible
Debentures, at the following prices (expressed as percentages of the principal
amount of the Convertible Debentures) (the "Optional Redemption Price") together
with accrued and unpaid interest (including Additional Sums, if any, and, to the
extent permitted by applicable law, Compounded Interest, if any) to, but
excluding, the redemption date, if redeemed during the 12-month period beginning
March 4, of the applicable year set forth below:

<TABLE>
<CAPTION>
                          Year   Redemption Price 
                         ------  -----------------
                         <S>     <C>              
                          2000            103.500%
                          2001            103.000%
                          2002            102.500%
                          2003            102.000%
                          2004            101.500%
                          2005            101.000%
                          2006            100.500% 
</TABLE>

and 100% if redeemed on or after March 4, 2007.

     If Convertible Debentures are redeemed on any March 1, June 1, September 1,
or December 1, accrued and unpaid interest shall be payable to holders of record
on the relevant record date.

     The Company may not redeem fewer than all of the outstanding Convertible
Debentures unless all accrued and unpaid interest has been paid on all
Convertible Debentures for all quarterly interest payment periods terminating on
or prior to the date of redemption.

     So long as the corresponding Trust Securities are outstanding, the proceeds
from the redemption of the Convertible Debentures will be used to redeem the
Trust Securities.

                                       50
<PAGE>
 
     If the Convertible Debentures are only partially redeemed pursuant to this
Section 10.2, the Convertible Debentures will be redeemed pro rata.  The
Optional Redemption Price, together with any required interest payment, shall be
paid prior to 12:00 noon, New York time, on the redemption date or at such
earlier time as the Company determines provided that the Company shall deposit
with the Trustee an amount sufficient to pay the Optional Redemption Price,
together with any required interest payment, by 10:00 a.m., New York time, on
the date such amounts are to be paid.  Partial redemptions must be in an amount
not less than $1,000 principal amount of Convertible Debentures.

     If Convertible Debentures selected for partial redemption are converted in
part before termination of the conversion right with respect to the portion of
the Convertible Debentures so selected, the converted portion of the Convertible
Debentures shall be deemed (so far as may be) to be the portion selected for
redemption.  Convertible Debentures (or portions thereof) which have been
converted during a selection of Convertible Debentures to be redeemed shall be
treated by the Trustee as Outstanding for the purpose of such selection.  In any
case where more than one Convertible Debenture is registered in the same name,
the Trustee in its discretion may treat the aggregate principal amount so
registered as if it were represented by one Convertible Debenture.

     If any Convertible Debenture called for redemption is converted into Common
Stock of the Company, any money deposited with the Trustee or with any Paying
Agent or so segregated and held in trust for the redemption of such Convertible
Debenture shall (subject to any right of the Holder of such Convertible
Debenture or any Predecessor Convertible Debenture to receive interest as
provided in the last paragraph of Section 2.9) be paid to the Company upon the
Company's request or, if then held by the Company, shall be discharged from such
trust.

     (b)  If a partial redemption of the Convertible Debentures would result in
the delisting of the Convertible Preferred Securities issued by the Trust from
any national securities exchange or other organization on which the Convertible
Preferred Securities are then listed, the Company shall not be permitted to
effect such partial redemption and may only redeem the Convertible Debentures in
whole.

     Section 10.3  No Sinking Fund.  The Convertible Debentures are not entitled
to the benefit of any sinking fund or subject to any sinking fund.

     Section 10.4  Election to Redeem; Notice of Redemption; Partial
Redemptions. The election of the Company to redeem any Convertible Debentures
shall be evidenced by, or pursuant to, a resolution of the Board of Directors.
Notice of redemption to the Holders of Convertible Debentures required to be
redeemed or to be redeemed as a whole or in part at the option of the Company
shall be given by giving notice of such redemption as provided in Section 15.4,
at least 30 days and not more than 60 days prior to the date fixed for
redemption to such Holders of Convertible Debentures. Any notice which is mailed
in the manner herein provided shall be conclusively presumed to have been duly
given, whether or not the Holder receives the notice. Neither the failure to
give notice by mail, nor any defect in the

                                       51
<PAGE>
 
notice so mailed to the Holder of any Convertible Debenture designated for
redemption as a whole or in part shall affect the validity of the proceedings
for such redemption.

     The notice of redemption to each such Holder shall specify the date fixed
for redemption, the "CUSIP" number or numbers for such Convertible Debentures,
the redemption price, the Place or Places of Payment, that payment will be made
upon presentation and surrender of such Convertible Debentures, that interest
accrued to the date fixed for redemption will be paid as specified in such
notice and that on and after said date interest thereon or on the portions
thereof to be redeemed will cease to accrue, the conversion rate or price, the
date on which the right to convert the Convertible Debentures to be redeemed
will terminate and the place or places where such Convertible Debentures may be
surrendered for conversion. If less than all of the Convertible Debentures are
to be redeemed, the notice of redemption shall specify the number of the
Convertible Debentures to be redeemed. In case any Convertible Debenture is to
be redeemed in part, the notice of redemption shall state the portion of the
principal amount thereof to be redeemed and shall state that on and after the
date fixed for redemption, upon surrender of such Convertible Debenture, a new
Convertible Debenture or Convertible Debentures in principal amount equal to the
unredeemed portion thereof will be issued.

     The notice of redemption of Convertible Debentures to be redeemed at the
option of the Company shall be given by the Company or, at the Company's
request, by the Trustee in the name and at the expense of the Company.  If such
notice is to be given by the Trustee, the Company shall provide notice of such
redemption to the Trustee at least 60 days prior to the date fixed for
redemption (unless a shorter notice shall be satisfactory to the Trustee).  If
such notice is given by the Company, the Company shall provide a copy of such
notice given to the Holders of such redemption to the Trustee at least 2 days
prior to the date such notice is given to such Holders, but in any event at
least 30 days and not more than 60 days prior to the date fixed for redemption.

     The Company or the Trust shall give public notice of any such redemption by
the issuance of a press release through the services of the Dow Jones Broad
Tape, Reuters News Service and Bloomberg News Service.

     Not later than the redemption date specified in the notice of redemption
given as provided in this Section, the Company will have on deposit with the
Trustee or with one or more Paying Agents (or, if the Company is acting as its
own Paying Agent, set aside, segregate and hold in trust as provided in Section
3.3) in funds available on such date an amount of money sufficient to redeem on
the redemption date all the Convertible Debentures so called for redemption at
the appropriate redemption price, together with accrued interest to the date
fixed for redemption.  If less than all of the Outstanding Convertible
Debentures are to be redeemed at the election of the Company, the Company will
deliver to the Trustee at least 60 days prior to the date fixed for redemption
(unless a shorter notice shall be satisfactory to the Trustee) an Officers'
Certificate stating the aggregate principal amount of Convertible Debentures to
be redeemed.

                                       52
<PAGE>
 
     For all purposes of this Indenture, unless the context otherwise requires,
all provisions relating to the redemption of Convertible Debentures shall
relate, in the case of any Convertible Debenture redeemed or to be redeemed only
in part, to the portion of the principal amount of such Convertible Debenture
which has been or is to be redeemed.

     Section 10.5  Payment of Convertible Debentures Called for Redemption.  If
notice of redemption has been given as above provided, the Convertible
Debentures or portions of Convertible Debentures specified in such notice shall
become due and payable on the date and at the place stated in such notice at the
applicable redemption price, together with interest accrued to the date fixed
for redemption, and on and after said date (unless the Company shall default in
the payment of such Convertible Debentures at the redemption price, together
with interest accrued to said date) interest on the Convertible Debentures or
portions of Convertible Debentures so called for redemption shall cease to
accrue, and, except as provided in Section 6.1, such Convertible Debentures
shall cease from and after the date fixed for redemption to be entitled to any
benefit or security under this Indenture, and the Holders thereof shall have no
right in respect of such Convertible Debentures except the right to receive the
redemption price thereof and unpaid interest to the date fixed for redemption.
On presentation and surrender of such Convertible Debentures at a Place of
Payment specified in said notice, said Convertible Debentures or the specified
portions thereof shall be paid and redeemed by the Company at the applicable
redemption price, together with interest accrued thereon to the date fixed for
redemption; provided that, payment of interest becoming due on or prior to the
date fixed for redemption shall be payable to the Holders of such Convertible
Debentures registered as such on the relevant record date subject to the terms
and provisions of Section 2.9 hereof.

     If any Convertible Debenture called for redemption shall not be so paid
upon surrender thereof for redemption, the principal shall, until paid or duly
provided for, bear interest from the date fixed for redemption at the Coupon
Rate.

     Upon presentation of any Convertible Debenture redeemed in part only, the
Company shall execute and the Trustee shall authenticate and make available for
delivery to or on the order of the Holder thereof, at the expense of the
Company, a new Convertible Debenture or Convertible Debentures, of authorized
denominations, in principal amount equal to the unredeemed portion of the
Convertible Debenture so presented.

     Section 10.6  Exclusion of Certain Convertible Debentures from Eligibility
for Selection for Redemption.  Convertible Debentures shall be excluded from
eligibility for selection for redemption if they are identified by registration
and certificate number in a written statement signed by an authorized officer of
the Company and delivered to the Trustee at least 30 days prior to the last date
on which notice of redemption may be given as being owned of record and
beneficially by, and not pledged or hypothecated by, either (a) the Company or
(b) an entity specifically identified in such written statement as directly or
indirectly controlling or controlled by or under direct or indirect common
control with the Company.

                                       53
<PAGE>
 
                                  ARTICLE XI

                     EXTENSION OF INTEREST PAYMENT PERIOD

     Section 11.1  Extension of Interest Payment Period.  As long as an Event of
Default under Section 5.1(a) of this Indenture shall not have occurred and be
continuing, the Company shall have the right, at any time and from time to time
during the term of the Convertible Debentures, to defer payments of interest by
extending the interest payment period of such Convertible Debentures for a
period not exceeding 20 consecutive quarters (the "Extension Period"), during
which Extension Period no interest shall be due and payable; provided that no
Extension Period may extend beyond the Maturity Date or any earlier redemption
date. To the extent permitted by applicable law, interest, the payment of which
has been deferred because of the extension of the interest payment period
pursuant to this Section 11.1, will bear interest thereon at the Coupon Rate
compounded quarterly for each quarter of the Extension Period ("Compound
Interest"). Each Extension Period, if any, will end on an Interest Payment Date.
At the end of the Extension Period, the Company shall pay all interest accrued
and unpaid on the Convertible Debentures, including any Additional Sums and, to
the extent permitted by law, Compound Interest (together, "Deferred Interest")
that shall be payable to the Holders of the Convertible Debentures in whose
names the Convertible Debentures are registered in the Security Register at the
close of business on the record date next preceding such Interest Payment Date.
Before the termination of any Extension Period, the Company may further extend
such period, provided that such period together with all previous and further
extensions thereof shall not exceed 20 consecutive quarters, or extend beyond
the Maturity Date or any earlier redemption date. Upon the termination of any
Extension Period and upon the payment of all Deferred Interest then due, the
Company may commence a new Extension Period, subject to the foregoing
requirements. No interest shall be due and payable during an Extension Period,
except at the end thereof, but the Company may prepay at any time all or any
portion of the interest accrued during an Extension Period.

     Section 11.2  Notice of Extension.

     (a)  If the Institutional Trustee is the only registered Holder of the
Convertible Debentures at the time the Company selects an Extension Period, the
Company shall give written notice to the Regular Trustees, the Institutional
Trustee and the Trustee of its selection of such Extension Period at least one
Business Day before the earlier of (i) the next succeeding date on which
Distributions on the Trust Securities issued by the Trust are payable, or (ii)
the date the Regular Trustees are required to give notice of the record date, or
the date such Distributions are payable, to the New York Stock Exchange or other
applicable self-regulatory organization or to holders of the Convertible
Preferred Securities issued by the Trust, but in any event at least ten Business
Days before such record date.  The Company shall cause the Trust to give notice
of the Company's selection of such Extension Period to holders of the
Convertible Preferred Securities.

     (b)  If the Institutional Trustee is not the only Holder of the Convertible
Debentures at the time the Company selects an Extension Period, the Company
shall give the

                                       54
<PAGE>
 
Holders of the Convertible Debentures, the Institutional Trustee and the Trustee
written notice of its selection of such Extension Period at least 10 Business
Days before the earlier of (i) the next succeeding Interest Payment Date or (ii)
the date the Company is required to give notice of the record or payment date of
such interest payment to the New York Stock Exchange or other applicable self-
regulatory organization or to Holders of the Convertible Debentures, but in any
event not less than two Business Days prior to such record date.

     (c)  The quarter in which any notice is given pursuant to paragraphs (a) or
(b) of this Section 11.2 shall be counted as one of the 20 consecutive quarters
permitted in the maximum Extension Period permitted under Section 11.1.


                                  ARTICLE XII

                     CONVERSION OF CONVERTIBLE DEBENTURES

     Section 12.1  Conversion Rights.  Subject to and upon compliance with the
provisions of this Article XII, the Convertible Debentures are convertible, at
the option of the Holders, at any time beginning May 21, 1997 through the close
of business on May 28, 2027 (or, in the case of Convertible Debentures called
for redemption, prior to the close of business on the Business Day prior to the
corresponding redemption date) into fully paid and nonassessable shares of
Common Stock of the Company at an initial conversion rate of .6709 shares of
Common Stock for each $50 in principal amount of Convertible Debentures
(equivalent to a conversion price of $74.53 per share of Common Stock (the
"Conversion Price")), subject to adjustment and reset as described in this
Article XII.  A Holder of Convertible Debentures may convert any portion of the
principal amount of the Convertible Debentures into that number of fully paid
and nonassessable shares of Common Stock obtained by dividing the principal
amount of the Convertible Debentures to be converted by such Conversion Price.
All calculations under this Article XII shall be made to the nearest cent or to
the nearest 1/100th of a share, as the case may be.

     Section 12.2  Conversion Procedures.

     (a)  In order to convert all or a portion of the Convertible Debentures,
the Holder thereof shall deliver to the Conversion Agent an irrevocable notice
of conversion (the "Notice of Conversion") setting forth the principal amount of
Convertible Debentures to be converted, together with the name or names, if
other than the Holder, in which the shares of Common Stock should be issued upon
conversion and, if such Convertible Debentures are definitive Convertible
Debentures, surrender to the Conversion Agent the Convertible Debentures to be
converted, duly endorsed or assigned to the Company or in blank. In addition, a
holder of Convertible Preferred Securities may exercise its right under the
Declaration to convert such Convertible Preferred Securities into Common Stock
by delivering to the Conversion Agent an irrevocable Notice of Conversion
setting forth the information called for by the preceding sentence and directing
the Conversion Agent (i) to exchange such Convertible Preferred Security for a
portion of the Convertible Debentures held by the Trust (at an exchange rate of
$50 principal amount of Convertible Debentures for each Convertible Preferred
Security) 

                                       55
<PAGE>
 
and (ii) to immediately convert such Convertible Debentures, on behalf of such
holder, into Common Stock of the Company pursuant to this Article XII and, if
such Convertible Preferred Securities are in definitive form, surrendering such
Convertible Preferred Securities, duly endorsed or assigned to the Company or in
blank. So long as any Convertible Preferred Securities are outstanding, the
Trust shall not convert any Convertible Debentures except pursuant to a Notice
of Conversion delivered to the Conversion Agent by a holder of Convertible
Preferred Securities.

     If a Notice of Conversion is delivered on or after the record date and
prior to the subsequent Interest Payment Date, the Holder will be entitled to
receive the interest payable on the subsequent Interest Payment Date on the
portion of Convertible Debentures to be converted notwithstanding the conversion
thereof prior to such Interest Payment Date. However, if a redemption date falls
between a record date and the subsequent Interest Payment Date, the Holder will
be entitled to receive, on such Interest Payment Date, the interest accrued to,
but excluding, the redemption date. Except as otherwise provided in the first
and second sentences of this paragraph, in the case of any Convertible Debenture
which is converted, interest whose Stated Maturity is after the date of
conversion of such Convertible Debenture shall not be payable, and the Company
shall not make nor be required to make any other payment, adjustment or
allowance with respect to accrued but unpaid interest on the Convertible
Debentures being converted, which shall be deemed to be paid in full. Each
conversion shall be deemed to have been effected immediately prior to the close
of business on the day on which the Notice of Conversion was received (the
"Conversion Date") by the Conversion Agent from the Holder or from a holder of
the Convertible Preferred Securities effecting a conversion thereof pursuant to
its conversion rights under the Declaration, as the case may be. The Person or
Persons entitled to receive the Common Stock issuable upon such conversion shall
be treated for all purposes as the record holder or holders of such Common Stock
as of the Conversion Date. As promptly as practicable on or after the Conversion
Date, the Company shall issue and deliver at the office of the Conversion Agent,
unless otherwise directed by the Holder in the Notice of Conversion, a
certificate or certificates for the number of full shares of Common Stock
issuable upon such conversion, together with the cash payment, if any, in lieu
of any fraction of any share to the Person or Persons entitled to receive the
same. The Conversion Agent shall deliver such certificate or certificates to
such Person or Persons.

     (b)  The Company's delivery upon conversion of the fixed number of shares
of Common Stock into which the Convertible Debentures are convertible (together
with the cash payment, if any, in lieu of fractional shares) shall be deemed to
satisfy the Company's obligation to pay the principal amount at Maturity of the
portion of Convertible Debentures so converted and any unpaid interest
(including Compound Interest) accrued on such Convertible Debentures at the time
of such conversion.

     (c)  No fractional shares of Common Stock will be issued as a result of
conversion, but in lieu thereof, the Company shall pay to the Conversion Agent a
cash adjustment in an amount equal to the same fraction of the Closing Price of
such fractional interest on the date on which the Convertible Debentures were
duly surrendered to the Conversion Agent for conversion, or, if such day is not
a Trading Day, on the next Trading 

                                       56
<PAGE>
 
Day, and the Conversion Agent in turn will make such payment, if any, to the
Holder of the Convertible Debentures or the holder of the Convertible Preferred
Securities so converted.

     (d)  In the event of the conversion of any Convertible Debenture in part
only, the Company shall execute and the Trustee shall authenticate and make
available for delivery to or on the order of the Holder thereof, at the expense
of the Company, a new Convertible Debenture or Convertible Debentures in the
aggregate principal amount equal to the unconverted portion thereof.

     (e)  In effecting the conversion transactions described in this Section
12.2, the Conversion Agent is acting as agent of the holders of Convertible
Preferred Securities (in the exchange of Convertible Preferred Securities for
Convertible Debentures) and as agent of the Holders of Convertible Debentures
(in the conversion of Convertible Debentures into Common Stock), as the case may
be. The Conversion Agent is hereby authorized (i) to exchange Convertible
Debentures held by the Trust from time to time for Convertible Preferred
Securities in connection with the conversion of such Convertible Preferred
Securities in accordance with this Article XII and (ii) to convert all or a
portion of the Convertible Debentures into Common Stock and thereupon to deliver
such shares of Common Stock in accordance with the provisions of this Article
XII and to deliver to the Trust a new Convertible Debenture or Convertible
Debentures for any resulting unconverted principal amount.

     Section 12.3  Conversion Price Adjustments.  The Conversion Price shall be
adjusted from time to time as follows:

     (a)  In case the Company shall, while any of the Convertible Debentures are
outstanding, (i) pay a dividend or make a distribution with respect to Common
Stock in shares of Common Stock, (ii) subdivide outstanding shares of Common
Stock, (iii) combine outstanding shares of Common Stock into a smaller number of
shares or (iv) issue by reclassification of its shares of Common Stock any
shares of capital stock of the Company, the conversion privilege and the
Conversion Price for the Convertible Debentures shall be adjusted so that the
Holder of any Convertible Debenture thereafter surrendered for conversion shall
be entitled to receive the number of shares of capital stock of the Company
which such Holder would have owned immediately following such action had such
Convertible Debenture been converted immediately prior thereto.  An adjustment
made pursuant to this subsection (a) shall become effective immediately after
the record date in the case of a dividend or other distribution and shall become
effective immediately after the effective date in case of a subdivision,
combination or reclassification (or immediately after the record date if a
record date shall have been established for such event).  If, as a result of an
adjustment made pursuant to this subsection (a), the Holder of any Convertible
Debenture thereafter surrendered for conversion shall become entitled to receive
shares of two or more classes or series of capital stock of the Company, the
Board of Directors (whose determination shall be conclusive and shall be
evidenced by a Board Resolution filed with the Trustee) shall determine the
allocation of the adjusted Conversion Price for the Convertible Debentures
between or among shares of such classes or series of capital stock.

                                       57
<PAGE>
 
     (b)  In case the Company shall, while any of the Convertible Debentures are
outstanding, issue rights or warrants to all holders of its Common Stock
entitling them (for a period expiring within 45 days after the record date
mentioned below) to subscribe for or purchase shares of Common Stock at a price
per share less than the current market price per share of Common Stock (as
determined pursuant to subsection (g) below) on the record date mentioned below,
the Conversion Price for the Convertible Debentures shall be adjusted so that
the same shall equal the price determined by multiplying the Conversion Price in
effect immediately prior to the date of issuance of such rights or warrants by a
fraction of which the numerator shall be the number of shares of Common Stock
outstanding on the date of issuance of such rights or warrants plus the number
of shares which the aggregate offering price of the total number of shares so
offered for subscription or purchase would purchase at such current market
price, and of which the denominator shall be the number of shares of Common
Stock outstanding on the date of issuance of such rights or warrants plus the
number of additional shares of Common Stock offered for subscription or
purchase. Such adjustment shall become effective immediately after the record
date for the determination of stockholders entitled to receive such rights or
warrants. To the extent that no shares of Common Stock are so delivered after
the expiration of such rights or warrants, the Conversion Price shall be
readjusted to the Conversion Price which would then be in effect if such date
fixed for the determination of stockholders entitled to receive such rights or
warrants had not been fixed. For the purposes of this subsection, the number of
shares of Common Stock at any time outstanding shall not include shares held in
the treasury of the Company. In case any rights or warrants referred to in this
subsection in respect of which an adjustment shall have been made shall expire
unexercised within 45 days after the same shall have been distributed or issued
by the Company, the Conversion Price shall be readjusted at the time of such
expiration to the Conversion Price that would have been in effect if no
adjustment had been made on account of the distribution or issuance of such
expired rights or warrants.

     (c)  Subject to the last sentence of this subsection (c), in case the
Company shall, by dividend or otherwise, distribute to all holders of its Common
Stock evidences of its indebtedness, shares of any class or series of capital
stock, cash or assets or rights or warrants to subscribe for or purchase any of
its securities (excluding any rights or warrants referred to in subsection (b),
any dividend or distribution paid exclusively in cash and any dividend or
distribution referred to in subsection (a) of this Section 12.3), the Conversion
Price shall be reduced so that the same shall equal the price determined by
multiplying the Conversion Price in effect immediately prior to the
effectiveness of the Conversion Price reduction contem plated by this subsection
(c) by a fraction of which the numerator shall be the current market price per
share (determined as provided in subsection (g)) of the Common Stock on the date
fixed for the payment of such distribution (the "Reference Date") less the fair
market value (as determined in good faith by the Board of Directors, whose
determination shall be conclusive and evidenced by a resolution of the Board of
Directors), on the Reference Date, of the portion of the evidences of
indebtedness, shares of capital stock, cash and assets so distributed or of such
subscription rights or warrants applicable to one share of Common Stock and the
denominator shall be such current market price per share of the Common Stock,
such reduc tion to become effective immediately prior to the opening of business
on the day following the Reference Date; provided, however, that in the

                                       58
<PAGE>
 
event the numerator shall be less than one, in lieu of the foregoing adjustment,
adequate provision shall be made so that each Holder of Convertible Debentures
shall have the right to receive upon conversion the amount of such distribution
such Holder would have received had such Holder converted each Convertible
Debenture immediately prior to the Reference Date. In the event that no such
dividend or distribution is so paid or made, the Conversion Price shall again be
adjusted to be the Conversion Price which would then be in effect if such
dividend or distribution had not occurred. If the Board of Directors determines
the fair market value of any distribution for purposes of this subsection (c) by
reference to the actual or when issued trading market for any securities
comprising such distribution, it must in doing so consider the prices in such
market over the same period used in computing the current market price per share
of Common Stock (determined as provided in subsection (g)). For purposes of this
subsection (c), any dividend or distribution that includes shares of Common
Stock, or rights or warrants of the type described in subsection (b), shall be
deemed instead to be a dividend or distribution of the evidences of
indebtedness, shares of capital stock, cash or assets or rights or warrants
other than such shares of Common Stock, or such rights or warrants of the type
described in subsection (b) (making any Conversion Price reduction required by
this subsection (c)), immediately followed by a dividend or distribution of such
shares of Common Stock or such rights or warrants of the type described in
subsection (b) (making any further Conversion Price adjustment required by
subsection (a) or (b)), except (A) the Reference Date of such dividend or
distribution as defined in this subsection (c) shall be substituted as (1) "the
record date in the case of a dividend or other distribution," and (2) "the
record date for the determination of stockholders entitled to receive such
rights or warrants" and (3) "the date fixed for such determination" within the
meaning of subsections (a) and (b) and (B) any shares of Common Stock included
in such dividend or distribution shall not be deemed outstanding for purposes of
computing any adjustment of the Conversion Price in subsection (b).

     (d)  In case the Company shall pay or make a dividend or other distribution
on its Common Stock exclusively in cash (excluding any quarterly cash dividend
on Common Stock to the extent that the aggregate cash dividend per share of
Common Stock in any quarter does not exceed the greater of (i) the amount per
share of Common Stock of the next preceding quarterly dividend on Common Stock
to the extent such preceding quarterly dividend did not require an adjustment of
the Conversion Price pursuant to this subsection (d) (as adjusted to reflect
subdivisions or combinations of Common Stock), and (ii) 3.75% of the daily
Closing Price per share determined as provided in subsection (g), and excluding
any dividend or distribution in connection with the liquidation, dissolution or
winding-up of the Company), the Conversion Price shall be reduced so that the
same shall equal the price determined by multiplying the Conversion Price in
effect immediately prior to the effectiveness of the Conversion Price reduction
contemplated by this subsection (d) by a fraction of which the numerator shall
be the current market price per share (determined as provided in subsection (g))
of the Common Stock on the date fixed for the payment of such distribution less
the amount of cash so distributed (and not excluded as provided above)
applicable to one share of Common Stock and the denominator shall be such
current market price per share of the Common Stock (determined as provided in
subsection (g)), such reduction to become effective immediately prior to the
opening of business on the day following the date fixed for the payment of such
distribution; provided, however, that in the 

                                       59
<PAGE>
 
event the portion of the cash so distributed applicable to one share of Common
Stock is equal to or greater than the current market price per share (as defined
in subsection (g)) of the Common Stock on the record date mentioned above, in
lieu of the foregoing adjustment, adequate provision shall be made so that each
Holder of shares of Convertible Debentures shall have the right to receive upon
conversion the amount of cash such Holder would have received had such Holder
converted each Convertible Debenture immediately prior to the record date for
the distribution of the cash. If an adjustment is required to be made pursuant
to this subsection (d) as a result of a distribution that is a quarterly
dividend, such adjustment shall be based upon the amount by which such
distribution exceeds the amount of the quarterly cash dividend permitted to be
excluded as provided above. If an adjustment is required to be made pursuant to
this subsec tion (d) as a result of a distribution that is not a quarterly
dividend, such adjustment shall be based upon the full amount of the
distribution. In the event that no such dividend or distribution is so paid or
made, the Conversion Price shall again be adjusted to be the Conversion Price
which would then be in effect if such Record Date had not been fixed.

     (e)  In case a tender or exchange offer (other than an odd-lot offer) made
by the Company or any Subsidiary of the Company for all or any portion of the
Company's Common Stock shall expire and such tender or exchange offer shall
involve the payment by the Company or such subsidiary of consideration per share
of Common Stock having a fair market value (as determined in good faith by the
Board of Directors, whose determination shall be conclusive and evidenced by a
resolution of the Board of Directors) at the last time (the "Expiration Time")
tenders or exchanges may be made pursuant to such tender or exchange offer (as
it shall have been amended) that exceeds the Closing Price of the Common Stock
on the Trading Day next succeeding the Expiration Time, the Conversion Price
shall be reduced so that the same shall equal the price determined by
multiplying the Conversion Price in effect immediately prior to the
effectiveness of the Conversion Price reduction contemplated by this subsection
(e) by a fraction (which shall not be greater than one) of which the numerator
shall be the number of shares of Common Stock outstanding (including any
tendered or exchanged shares) at the Expiration Time multiplied by the Closing
Price of the Common Stock on the Trading Day next succeeding the Expiration Time
and the denominator shall be the sum of (i) the fair market value (determined as
aforesaid) of the aggregate consideration payable to stockholders based on the
acceptance (up to any maximum specified in the terms of the tender or exchange
offer) of all shares validly tendered or exchanged and not withdrawn as of the
Expiration Time (the shares deemed so accepted, up to any such maximum, being
referred to as the "Purchased Shares") and (ii) the product of the number of
shares of Common Stock outstanding (less any Purchased Shares) at the Expiration
Time and the Closing Price of the Common Stock on the Trading Day next
succeeding the Expiration Time, such reduction to become retroactively effective
immediately prior to the opening of business on the day following the Expiration
Time.

     (f)  In case a tender or exchange offer made by a Person other than the
Company or any Subsidiary of the Company for all or any portion of the Common
Stock shall expire and such tender or exchange offer shall involve the payment
by a Person other than the Company or any Subsidiary of the Company of
consideration per share of Common Stock having a fair market value (as
determined in good faith by the Board of Directors, whose 

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<PAGE>
 
determination shall be conclusive and evidenced by a resolution of the Board of
Directors) at the applicable Expiration Time that exceeds the Closing Price of
the Common Stock on the Trading Day next succeeding the applicable Expiration
Time in which as of the closing date of the offer the Board of Directors of the
Company is not recommending rejection of the offer, the Conversion Price shall
be reduced so that the same shall equal the price determined by multiplying the
Conversion Price in effect immediately prior to the effectiveness of the
Conversion Price reduction contemplated by this subsection (f) by a fraction
(which shall not be greater than one) of which the numerator shall be the number
of shares of Common Stock outstanding (including any tendered or exchanged
shares) at the Expiration Time multiplied by the Closing Price of the Common
Stock on the Trading Day next succeeding the Expiration Time and the
denominator shall be the sum of (i) the fair market value (determined as
aforesaid) of the aggregate consideration payable to stockholders based on the
acceptance (up to any maximum specified in the terms of the tender or exchange
offer) of the Purchased Shares and, (ii) the product of the number of shares of
Common Stock outstanding (less any Purchased Shares) at the Expiration Time and
the Closing Price of the Common Stock on the Trading Day next succeeding the
Expiration Time, such reduction to become retroactively effective immediately
prior to the opening of business on the day following the Expiration Time;
provided, however, that the reduction of the Conversion Price contemplated by
this subsection (f) will only be made if the tender offer or exchange offer is
made for an amount which increases that Person's ownership of Common Stock to
more than 25% of the total shares of Common Stock outstanding and provided,
further, that the reduction of the Conversion Price contemplated by this
subsection (f) will not be made if as of the close of the offer, the offering
documents with respect to such offer disclose a plan or an intention to cause
the Company to engage in a consolidation or merger of the Company or a sale of
all or substantially all of the assets of the Company.

     (g)  For the purpose of any computation under subsection (b), (c) or (d),
the current market price per share of Common Stock on any date in question shall
be deemed to be the average of the daily Closing Prices for the ten Trading Day
period ending on the earlier of the day in question and, if applicable, the day
before the "ex" date with respect to the issuance or distribution requiring such
computation; provided, however, that if more than one event occurs that would
require an adjustment pursuant to subsections (a) through (f), inclusive, the
Board of Directors may make such adjustments to the Closing Prices during such
ten Trading Day period as it deems appropriate to effectuate the intent of the
adjustments in this Section 12.3, in which case any such determination by the
Board of Directors shall be set forth in a Board Resolution and shall be
conclusive.  For purposes of this paragraph, the term "ex" date, (1) when used
with respect to any issuance or distribution, means the first date on which the
Common Stock trades regular way on the New York Stock Exchange or on such
successor securities exchange as the Common Stock may be listed or in the
relevant market from which the Closing Prices were obtained without the right to
receive such issuance or distribution, and (2) when used with respect to any
tender or exchange offer means the first date on which the Common Stock trades
regular way on such securities exchange or in such market after the Expiration
Time of such offer.

     (h)  The Company may make such reductions in the Conversion Price, in
addition to those required by subsections (a) through (f), as the Board of
Directors considers to be 

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<PAGE>
 
advisable to avoid or diminish any income tax to holders of Common Stock or
rights to purchase Common Stock resulting from any dividend or distribution of
stock (or rights to acquire stock) or from any event treated as such for income
tax purposes. The Company from time to time may reduce the Conversion Price by
any amount for any period of time if the period is at least twenty (20) days.
Whenever the Conversion Price is reduced pursuant to the preceding sentence, the
Company shall mail to Holders of record of the Convertible Debentures a notice
of the reduction at least 15 days prior to the date the reduced Conversion Price
takes effect, and such notice shall state the reduced Conversion Price and the
period it will be in effect.

     (i)  No adjustment in the Conversion Price shall be required unless such
adjustment would require an increase or decrease of at least 1% in the
Conversion Price; provided, however, that any adjustments which by reason of
this subsection (i) are not required to be made shall be carried forward and
taken into account in determining whether any subsequent adjustment shall be
required.

     (j)  If any action would require adjustment of the Conversion Price
pursuant to more than one of the provisions described above, only one adjustment
shall be made and such adjustment shall be the amount of adjustment that has the
highest absolute value to the Holder of Convertible Debentures.

     (k)  Except as stated above, the Conversion Rate will not be adjusted for
the issuance of Common Stock or any securities convertible into, or exchangeable
for, Common Stock, or carrying the right to purchase any of the foregoing.

     Section 12.4  Merger, Consolidation or Sale of Assets.

     (a)  In the event that the Company shall be a party to any transaction
(including without limitation (i) any recapitalization or reclassification of
the Common Stock (other than a change in par value, or from par value to no par
value, or from no par value to par value, or as a result of a subdivision or
combination of the Common Stock), (ii) any consolidation of the Company with, or
merger of the Company into, any other Person, any merger of another Person into
the Company (other than a merger which does not result in a reclassification,
conversion, exchange or cancellation of outstanding shares of Common Stock of
the Company), (iii) any sale or transfer of all or substantially all of the
assets of the Company or (iv) any compulsory share exchange) pursuant to which
either shares of Common Stock shall be converted into the right to receive other
securities, cash or other property, or, in the case of a sale or transfer of all
or substantially all of the assets of the Company, the holders of Common Stock
shall be entitled to receive other securities, cash or other property, then
lawful provision shall be made as part of the terms of such transaction whereby
the Holder of each Convertible Debenture then outstanding shall have the right
thereafter to convert such Convertible Debenture only into:

          (i)  in the case of any such transaction that does not constitute a
     Common Stock Fundamental Change and subject to funds being legally
     available for such purpose under applicable law at the time of such
     conversion, the kind and amount of 

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<PAGE>
 
     the securities, cash or other property that would have been receivable upon
     such recapitalization, reclassification, consolidation, merger, sale,
     transfer or share exchange by a holder of the number of shares of Common
     Stock issuable upon conversion of such Convertible Debenture immediately
     prior to such recapitalization, reclassification, consolidation, merger,
     sale, transfer or share exchange, after giving effect, in the case of any
     Non-Stock Fundamental Change, to any adjustment in the Conversion Price in
     accordance with clause (i) of subsection (c) of this Section 12.4; and

          (ii) in the case of any such transaction that constitutes a Common
     Stock Fundamental Change, common stock of the kind received by holders of
     Common Stock as a result of such Common Stock Fundamental Change in an
     amount determined in accordance with clause (ii) of subsection (c) of this
     Section 12.4.

     (b)  The Company or the Person formed by such consolidation or resulting
from such merger or which acquired such assets or which acquires the Company's
shares, as the case may be, shall make provision in its certificate or articles
of incorporation or other constituent document to establish such right.  Such
certificate or articles of incorporation or other constituent document shall
provide for adjustments which, for events subsequent to the effective date of
such certificate or articles of incorporation or other constituent document,
shall be as nearly equivalent as may be practicable to the adjustments provided
for in this Article XII.  The above provisions shall similarly apply to
successive transactions of the foregoing type.

     (c)  Notwithstanding any other provision of this Section 12.4 to the
contrary, if any Fundamental Change occurs, then the Conversion Price in effect
will be adjusted immediately after such Fundamental Change as follows:

          (i)  in the case of a Non-Stock Fundamental Change, the Conversion
     Price of the Convertible Debentures immediately following such Non-Stock
     Fundamental Change shall be the lower of (A) the Conversion Price in effect
     immediately prior to such Non-Stock Fundamental Change, but after giving
     effect to any other prior adjustments effected pursuant to Section 12.3,
     and (B) the product of (1) the greater of the Applicable Price and the then
     applicable Reference Market Price and (2) a fraction, the numerator of
     which is $50 and the denominator of which is (x) the amount of the Optional
     Redemption Price set forth in Section 10.2 for $50 in principal amount of
     Convertible Debentures if the redemption date were the date of such Non-
     Stock Fundamental Change (or, for the twelve-month periods commencing March
     4, 1997, March 4, 1998 and March 4, 1999, the product of 105.0%, 104.5% and
     104.0%, respectively, times $50) plus (y) any then-accrued and unpaid
     interest on $50 principal amount of Convertible Debentures; and

          (ii) in the case of a Common Stock Fundamental Change, the Conversion
     Price of the Convertible Debentures immediately following such Common Stock
     Fundamental Change shall be the Conversion Price in effect immediately
     prior to such Common Stock Fundamental Change, but after giving effect to
     any other prior 

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<PAGE>
 
     adjustments effected pursuant to Section 12.3, multiplied by a fraction,
     the numerator of which is the Purchaser Stock Price and the denominator of
     which is the Applicable Price; provided, however, that in the event of a
     Common Stock Fundamental Change in which (A) 100% of the value of the
     consideration received by a holder of Common Stock is common stock of the
     successor, acquiror or other third party (and cash, if any, paid with
     respect to any fractional interests in such common stock resulting from
     such Common Stock Fundamental Change) and (B) all of the Common Stock shall
     have been exchanged for, converted into or acquired for, common stock of
     the successor, acquiror or other third party (and any cash with respect to
     fractional interests), the Conversion Price of the Convertible Debentures
     immediately following such Common Stock Fundamental Change shall be the
     Conversion Price in effect immediately prior to such Common Stock
     Fundamental Change multiplied by a fraction, the numerator of which is one
     (1) and the denominator of which is the number of shares of common stock of
     the successor, acquiror or other third party received by a holder of one
     share of Common Stock as a result of such Common Stock Fundamental Change.

     Section 12.5  Notice of Adjustments of Conversion Price.  Whenever the
Conversion Price is adjusted as herein provided:

          (a)  the Company shall compute the adjusted Conversion Price and shall
     prepare a certificate signed by the Chief Financial Officer or the
     Treasurer of the Company setting forth the adjusted Conversion Price and
     showing in reasonable detail the facts upon which such adjustment is based,
     and such certificate shall forthwith be filed with the Trustee and the
     transfer agent for the Convertible Preferred Securities and the Convertible
     Debentures; and

          (b)  a notice stating the Conversion Price has been adjusted and
     setting forth the adjusted Conversion Price shall as soon as practicable be
     mailed by the Company to all record holders of Convertible Preferred
     Securities and the Convertible Debentures at their last addresses as they
     appear upon the transfer books of the Company and the Trust.

     Section 12.6  Prior Notice of Certain Events.  In case:

          (a)  the Company shall (i) declare any dividend (or any other
     distribution) on its Common Stock, other than (A) a dividend payable in
     shares of Common Stock or (B) a dividend payable in cash that would not
     require an adjustment pursuant to Section 12.3(c) or (d) or (ii) authorize
     a tender or exchange offer that would require an adjustment pursuant to
     Section 12.3(e);

          (b)  the Company shall authorize the granting to all holders of Common
     Stock of rights or warrants to subscribe for or purchase any shares of
     stock of any class or series or of any other rights or warrants;

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<PAGE>
 
          (c)  of any reclassification of Common Stock (other than a subdivision
     or combination of the outstanding Common Stock, or a change in par value,
     or from par value to no par value, or from no par value to par value), or
     of any consolidation or merger to which the Company is a party and for
     which approval of any stockholders of the Company shall be required, or of
     the sale or transfer of all or substantially all of the assets of the
     Company or of any compulsory share exchange whereby the Common Stock is
     converted into other securities, cash or other property; or

          (d)  of the voluntary or involuntary dissolution, liquidation or
     winding up of the Company;

then the Company shall (i) if any Convertible Preferred Securities are
outstanding, cause to be filed with the transfer agent for the Convertible
Preferred Securities, and shall cause to be mailed to the holders of record of
the Convertible Preferred Securities, at their last addresses as they shall
appear upon the stock transfer books of the Trust or (ii) shall cause to be
mailed to all Holders at their last addresses as they shall appear in the
Security Register, at least 15 days prior to the applicable record or effective
date hereinafter specified, a notice stating (A) the date on which a record (if
any) is to be taken for the purpose of such dividend, distribution, rights or
warrants or, if a record is not to be taken, the date as of which the holders of
Common Stock of record to be entitled to such dividend, distribution, rights or
warrants are to be determined or (B) the date on which such reclassification,
consolidation, merger, sale, transfer, share exchange, dissolution, liquidation
or winding up is expected to become effec tive, and the date as of which it is
expected that holders of Common Stock of record shall be entitled to exchange
their shares of Common Stock for securities, cash or other property deliverable
upon such reclassification, consolidation, merger, sale, transfer, share
exchange, dissolution, liquidation or winding up (but no failure to mail such
notice or any defect therein or in the mailing thereof shall affect the validity
of the corporate action required to be specified in such notice). If at any time
the Trustee shall not be the Conversion Agent, a copy of such notice shall also
forthwith be filed by the Company with the Trustee.

     Section 12.7  Certain Additional Rights.  In case the Company shall, by
dividend or otherwise, declare or make a distribution on the Common Stock
referred to in Section 12.3(c) or 12.3(d)), the Holder of the Convertible
Debentures, upon the conversion thereof subsequent to the close of business on
the date fixed for the determination of stockholders entitled to receive such
distribution and prior to the effectiveness of the Conversion Price adjustment
in respect of such distribution, shall also be entitled to receive for each
share of Common Stock into which the Convertible Debentures are converted, the
portion of the shares of Common Stock, rights, warrants, evidences of
indebtedness, shares of capital stock, cash and assets so distributed applicable
to one share of Common Stock; provided, however, that, at the election of the
Company (whose election shall be evidenced by a resolution of the Board of
Directors) with respect to all Holders so converting, the Company may, in lieu
of distributing to such Holder any portion of such distribution not consisting
of cash or securities of the Company, pay such Holder an amount in cash equal to
the fair market value thereof (as determined in good faith by the Board of
Directors, whose determination shall be conclusive and evidenced by a resolution
of the Board of Directors).  

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<PAGE>
 
If any conversion of Convertible Debentures described in the immediately
preceding sentence occurs prior to the payment date for a distribution to
holders of Common Stock which the Holder of Convertible Debentures so converted
is entitled to receive in accordance with the immediately preceding sentence,
the Company may elect (such election to be evidenced by a resolution of the
Board of Directors) to distribute to such Holder a due bill for the shares of
Common Stock, rights, warrants, evidences of indebtedness, shares of capital
stock, cash or assets to which such Holder is so entitled, provided, that such
due bill (a) meets any applicable requirements of the principal national
securities exchange or other market on which the Common Stock is then traded and
(b) requires payment or delivery of such shares of Common Stock, rights,
warrants, evidences of indebtedness, shares of capital stock, cash or assets no
later than the date of payment or delivery thereof to holders of shares of
Common Stock receiving such distribution.

     Section 12.8  Trustee Not Responsible for Determining Conversion Price or
Adjustments.  Neither the Trustee nor any Conversion Agent shall at any time be
under any duty or responsibility to any Holder of any Convertible Debenture to
determine whether any facts exist which may require any adjustment of the
Conversion Price, or with respect to the nature or extent of any such adjustment
when made, or with respect to the method employed. Neither the Trustee nor any
Conversion Agent shall be accountable with respect to the validity or value (or
the kind or amount) of any shares of Common Stock or of any securities or
property, which may at any time be issued or delivered upon the conversion of
any Conver tible Debenture; and neither the Trustee nor any Conversion Agent
makes any representation with respect thereto. Neither the Trustee nor any
Conversion Agent shall be responsible for any failure of the Company to make any
cash payment or to issue, transfer or deliver any shares of Common Stock or
stock certificates or other securities or property upon the surrender of any
Convertible Debenture for the purpose of conversion. All Convertible Debentures
delivered for conversion shall be delivered to the Trustee to be cancelled by or
at the discretion of the Trustee, which shall dispose of the same as provided in
Section 2.12 of this Indenture.

     Section 12.9  Reservation of Shares of Common Stock.  The Company shall at
all times reserve and keep available, free from preemptive rights, out of its
authorized but unissued Common Stock or treasury shares, for the purpose of
effecting the conversion of Convertible Debentures, the full number of shares of
Common Stock of the Company then issuable upon the conversion of all outstanding
Convertible Debentures.

     Section 12.10  Payment of Certain Taxes upon Conversion.  The Company will
pay any and all taxes that may be payable in respect of the issue or delivery of
shares of its Common Stock on conversion of Convertible Debentures pursuant
hereto.  The Company shall not, however, be required to pay any tax which may be
payable in respect of any transfer involved in the issue and delivery of shares
of its Common Stock in a name other than that of the Holder of the Convertible
Debenture or Convertible Debentures to be converted, and no such issue or
delivery shall be made unless and until the person requesting such issue has
paid to the Company the amount of any such tax, or has established, to the
satisfaction of the Company, that such tax has been paid.

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<PAGE>
 
     Section 12.11  Nonassessability.  The Company covenants that all shares of
Common Stock which may be issued upon conversion of Convertible Debentures will
upon issue in accordance with the terms hereof be duly and validly issued and
fully paid and nonassessable.


                                 ARTICLE XIII

                    SUBORDINATION OF CONVERTIBLE DEBENTURES

     Section 13.1  Convertible Debentures Subordinate to Senior Indebtedness.
The Company covenants and agrees, and each Holder of a Convertible Debenture, by
the Holder's acceptance thereof, likewise covenants and agrees, that, to the
extent and in the manner hereinafter set forth in this Article, the indebtedness
represented by the Convertible Debentures and the payment of the principal of
(and premium, if any) and interest on each and all of the Convertible Debentures
are hereby expressly made subordinate and junior in right of payment to the
prior payment in full of all Senior Indebtedness of the Company, whether
outstanding at the date of this Indenture or thereafter incurred. No provision
of this Article shall prevent the occurrence of any default or Event of Default
hereunder.

     Section 13.2  Payment Over of Proceeds upon Dissolution, Etc.  In the event
of (i) any insolvency, bankruptcy, receivership, liquidation, reorganization,
readjustment, composition or other similar proceeding relating to the Company,
its creditors or its property, (ii) any proceeding for the liquidation,
dissolution or other winding up of the Company voluntarily or involuntarily,
whether or not involving insolvency or bankruptcy proceedings, (iii) any
assignment by the Company for the benefit of creditors or (iv) any other
marshalling of assets of the Company, all amounts due upon all Senior
Indebtedness of the Company (including any interest thereon accruing after the
commencement of such proceedings) shall first be paid in full, or payment
thereof provided for in money in accordance with its terms, before any payment
is made by the Company on account of the principal (and premium, if any) or
interest on the Convertible Debentures; and any payment by the Company, or
distribution of assets of the Company of any kind or character, whether in cash,
property or securities, to which the Holders of the Convertible Debentures or
the Trustee would be entitled to receive from the Company, except for the
provisions of this Article, shall be paid by the Company or by any receiver,
trustee in bankruptcy, liquidation trustee, agent or other Person making such
payment or distribution, or by the Holders of the Convertible Debentures or by
the Trustee under this Indenture if received by them or it, directly to the
holders of Senior Indebtedness of the Company (pro rata to such holders on the
basis of the respective amounts of Senior Indebtedness held by such holders, as
calculated by the Company) or their representative or representatives, or to the
trustee or trustees under any indenture pursuant to which any instruments
evidencing such Senior Indebtedness may have been issued, as their respective
interests may appear, to the extent necessary to pay such Senior Indebtedness
(including any interest thereon accruing after the commencement of such
proceedings) in full, after giving effect to any concurrent payment or
distribution to or for the holders of such Senior Indebtedness, before any
payment or distribution is made to the Holders of the Convertible Debentures or
to the Trustee.

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<PAGE>
 
     In the event that, notwithstanding the foregoing, any payment or
distribution of assets of the Company of any kind or character, whether in cash,
property or securities, prohibited by the foregoing, shall be received by the
Trustee before all Senior Indebtedness of the Company is paid in full, or
provision is made for such payment, such payment or distribution shall be held
in trust for the benefit of and shall be paid over or delivered to the holders
of such Senior Indebtedness or their representative or representatives, or to
the trustee or trustees under any indenture pursuant to which any instruments
evidencing such Senior Indebtedness may have been issued, and their respective
interests may appear, as calculated by the Company, for application to the
payment of all Senior Indebtedness of the Company, as the case may be, remaining
unpaid to the extent necessary to pay such Senior Indebtedness in full, after
giving effect to any concurrent payment or distribution to or for the benefit of
the holders of such Senior Indebtedness.

     For purposes of this Article only, the words "cash, property or securities"
shall not be deemed to include shares of stock of the Company as reorganized or
readjusted, or securities of the Company or any other corporation provided for
by a plan of reorganization or readjustment which are subordinated in right of
payment to all Senior Indebtedness which may at the time be outstanding to
substantially the same extent as, or to a greater extent than, the Convertible
Debentures are so subordinated as provided in this Article. The consolidation of
the Company with, or the merger of the Company into, another Person or the
liquidation or dissolution of the Company following the conveyance or transfer
of its properties and assets substantially as an entirety to another Person upon
the terms and conditions set forth in Article IX of this Indenture shall not be
deemed a dissolution, winding up, liquidation, reorganization, readjustment,
composition, assignment for the benefit of creditors or marshalling of assets
and liabilities of the Company for the purposes of this Section if the Person
formed by such consolidation or into which the Company is merged or the Person
which acquires by conveyance or transfer such properties and assets
substantially as an entirety, as the case may be, shall, as a part of such
consolidation, merger, conveyance or transfer, comply with the conditions set
forth in Article IX of this Indenture.

     Section 13.3  Prior Payment to Senior Indebtedness upon Acceleration of
Convertible Debentures.  In the event that any Convertible Debentures are
declared due and payable before their Stated Maturity, then and in such event
the holders of Senior Indebtedness shall be entitled to receive payment in full
of all amounts due or to become due on or in respect of all Senior Indebtedness
or provision shall be made for such payment in cash, before the Holders of the
Convertible Debentures are entitled to receive any payment (including any
payment which may be payable by reason of the payment of any other indebtedness
of the Company being subordinated to the payment of the Convertible Debentures)
by the Company on account of the principal of (or premium, if any) or interest
on the Convertible Debentures or on account of the purchase or other acquisition
of Convertible Debentures.

     In the event that, notwithstanding the foregoing, the Company shall make
any payment to the Trustee or the Holder of any Convertible Debenture prohibited
by the foregoing provisions of this Section, and if such fact shall, at or prior
to the time of such payment, have been made known to the Trustee or, as the case
may be, such Holder, then and in such event such payment shall be paid over and
delivered forthwith to the Company.

                                       68
<PAGE>
 
     The provisions of this Section shall not apply to any payment with respect
to which Section 13.2 would be applicable.

     Section 13.4  No Payment When Senior Indebtedness in Default.  In the event
and during the continuation of any default by the Company in the payment of
principal, premium, if any, interest or any other payment due on any Senior
Indebtedness of the Company, as the case may be, beyond any applicable grace
period with respect thereto, or in the event that the maturity of any Senior
Indebtedness of the Company has been accelerated because of a default, then, in
any such case, no payment shall be made by the Company with respect to the
principal (including redemption payments, if any) of, premium, if any, or
interest on the Convertible Debentures until such default is cured or waived or
ceases to exist or any such acceleration or demand for payment has been
rescinded.

     Section 13.5  Payment Permitted in Certain Situations.  Nothing contained
in this Article or elsewhere in this Indenture or in the Convertible Debentures
shall prevent (a) the Company, at any time except during the pendency of any
dissolution, winding-up, liquidation or reorganization of the Company, whether
voluntary or involuntary or any bankruptcy, insolvency, receivership or other
proceedings of the Company referred to in Section 13.2 or under the conditions
described in Section 13.3 or 13.4, from making payments at any time of principal
of or premium, if any, or interest on the Convertible Debentures, or (b) the
application by the Trustee of any money deposited with it hereunder to the
payment of or on account of the principal of, or premium, if any, or interest on
the Convertible Debentures or the retention of such payment by the Holders, if,
at the time of such application by the Trustee, it did not have knowledge that
such payment would have been prohibited by the provisions of this Article.

     Section 13.6  Subrogation to Rights of Holders of Senior Indebtedness.
Subject to the payment in full of all Senior Indebtedness or the provision for
such payment in cash or cash equivalents or otherwise in a manner satisfactory
to the holders of Senior Indebtedness, the rights of the Holders of Convertible
Debentures shall be subrogated to the extent of the payments or distributions
made to the holders of such Senior Indebtedness pursuant to the provisions of
this Article (equally and ratably with the holders of indebtedness of the
Company which by its express terms is subordinated to indebtedness of the
Company to substantially the same extent as the Convertible Debentures are
subordinated to the Senior Indebtedness and is entitled to like rights of
subrogation) to the rights of the holders of such Senior Indebtedness to receive
payments and distributions of cash, property and securities applicable to the
Senior Indebtedness until the principal of (and premium, if any) and interest on
the Convertible Debentures shall be paid in full.  For purposes of such
subrogation, no payments or distributions to the holders of the Senior
Indebtedness of any cash, property or securities to which the Holders of
Convertible Debentures or the Trustee would be entitled except for the
provisions of this Article, and no payments over pursuant to the provisions of
this Article to or for the benefit of the holders of Senior Indebtedness by
Holders of Convertible Debentures or the Trustee, shall, as among the Company,
its creditors other than holders of Senior Indebtedness and the Holders of
Convertible Debentures, be deemed to be a payment or distribution by the Company
to or on account of the Senior Indebtedness.

                                       69
<PAGE>
 
     Section 13.7  Provisions Solely to Define Relative Rights.  The provisions
of this Article are and are intended solely for the purpose of defining the
relative rights of the Holders of Convertible Debentures on the one hand and the
holders of Senior Indebtedness on the other hand.  Nothing contained in this
Article or elsewhere in this Indenture or in the Convertible Debentures is
intended to or shall (a) impair, as among the Company, its creditors other than
holders of Senior Indebtedness and the Holders of Convertible Debentures, the
obligation of the Company, which is absolute and unconditional (and which,
subject to the rights under this Article of the holders of Senior Indebtedness,
is intended to rank equally with all other general obligations of the Company),
to pay to the Holders of Convertible Debentures the principal of (and premium,
if any) and interest on the Convertible Debentures as and when the same shall
become due and payable in accordance with their terms; or (b) affect the
relative rights against the Company of the Holders of Convertible Debentures and
creditors of the Company, as the case may be, other than the holders of Senior
Indebtedness; or (c) prevent the Trustee or the Holder of any Convertible
Debenture from exercising all remedies otherwise permitted by applicable law
upon default under this Indenture, subject to the rights, if any, under this
Article of the holders of Senior Indebtedness to receive cash, property and
securities otherwise payable or deliverable to the Trustee or such Holder.

     Section 13.8  Trustee to Effectuate Subordination.  Each Holder of a
Convertible Debenture by such Holder's acceptance thereof authorizes and directs
the Trustee on such Holder's behalf to take such action as may be necessary or
appropriate to effectuate the subordination provided in this Article and
appoints the Trustee such Holder's attorney-in-fact for any and all such
purposes.

     Section 13.9  No Waiver of Subordination Provisions.  No right of any
present or future holder of any Senior Indebtedness to enforce subordination as
herein provided shall at any time in any way be prejudiced or impaired by any
act or failure to act on the part of the Company or by any act or failure to
act, in good faith, by any such holder, or by any noncompliance by the Company
with the terms, provisions and covenants of this Indenture, regardless of any
knowledge thereof any such holder may have or be otherwise charged with.

     Without in any way limiting the generality of the foregoing paragraph, the
holders of Senior Indebtedness may, at any time and from time to time, without
the consent of or notice to the Trustee or the Holders of the Convertible
Debentures, without incurring responsibility to the Holders of Convertible
Debentures and without impairing or releasing the subordination provided in this
Article or the obligations hereunder of the Holders of Convertible Debentures to
the holders of Senior Indebtedness do any one or more of the following (a)
change the manner, place or terms of payment or extend the time of payment of,
or renew or alter, Senior Indebtedness or otherwise amend or supplement in any
manner Senior Indebtedness or any instrument evidencing the same or any
agreement under which Senior Indebtedness is outstanding; (b) sell, exchange,
release or otherwise deal with any property pledged, mortgaged or otherwise
securing Senior Indebtedness; (c) release any Person liable in any manner for
the collection of Senior Indebtedness; and (d) exercise or refrain from
exercising any rights against the Company and any other Person.

                                       70
<PAGE>
 
     Section 13.10  Notice to Trustee.  The Company shall give prompt written
notice to a Responsible Officer of the Trustee of any fact known to the Company
which would prohibit the making of any payment to or by the Trustee in respect
of the Convertible Debentures pursuant to the provisions of this Article.
Notwithstanding the provisions of this Article or any other provision of this
Indenture, the Trustee shall not be charged with knowledge of the existence of
any facts which would prohibit the making of any payment to or by the Trustee in
respect of the Convertible Debentures pursuant to the provisions of this
Article, unless and until a Responsible Officer of the Trustee shall have
received written notice thereof from the Company or a holder or holders of
Senior Indebtedness or from any trustee therefor; and, prior to the receipt of
any such written notice, the Trustee, subject to the provisions of Section 6.2
of this Indenture, shall be entitled in all respects to assume that no such
facts exist; provided, however, that if the Trustee shall have not received the
notice provided for in this Section at least two Business Days prior to the date
upon which by the terms hereof any money may become payable for any purpose
(including, without limitation, the payment of the principal of (or premium, if
any) or interest on any Convertible Debentures, then, anything herein contained
to the contrary notwithstanding, the Trustee shall have full power and authority
to receive such money and to apply the same to the purposes for which they were
received, and shall not be affected by any notice to the contrary that may be
received by it within two Business Days prior to such date.

     Subject to the provisions of Section 6.2 of this Indenture, the Trustee
shall be entitled to rely on the delivery to it of a written notice by a Person
representing himself to be a holder of Senior Indebtedness (or a trustee
therefor) to establish that such notice has been given by a holder of Senior
Indebtedness (or a trustee therefor).  In the event that the Trustee determines
in good faith that further evidence is required with respect to the right of any
Person as a holder of Senior Indebtedness to participate in any payment or
distribution pursuant to this Article, the Trustee may request such Person to
furnish evidence to the reasonable satisfaction of the Trustee as to the amount
of Senior Indebtedness held by such Person, the extent to which such Person is
entitled to participate in such payment or distribution and any other facts
pertinent to the rights of such Person under this Article, and if such evidence
is not furnished, the Trustee may defer any payment to such Person pending
judicial determination as to the right of such Person to receive such payment.

     Section 13.11  Reliance on Judicial Order or Certificate of Liquidating
Agent.  Upon any payment or distribution of assets of the Company referred to in
this Article, the Trustee, subject to the provisions of Section 6.2 of this
Indenture, and the Holders of Convertible Debentures shall be entitled to
conclusively rely upon any order or decree entered by any court of competent
jurisdiction in which such insolvency, bankruptcy, receivership, liquidation,
reorganization, dissolution, winding up or similar case or proceeding is
pending, or a certificate of the trustee in bankruptcy, receiver, liquidating
trustee, custodian, assignee for the benefit of creditors, agent or other Person
making such payment or distribution, delivered to the Trustee or to the Holders
of Convertible Debentures, for the purpose of ascertaining the Persons entitled
to participate in such payment or distribution, the holders of Senior
Indebtedness and other indebtedness of the Company, as the case may be, the
amount thereof or payable thereon, the amount or amounts paid or distributed
thereon and all other facts pertinent thereto or to this Article.

                                       71
<PAGE>
 
     Section 13.12  Trustee Not Fiduciary for Holders of Senior Indebtedness.
With respect to the holders of Senior Indebtedness, the Trustee undertakes to
perform or to observe only such of its covenants and obligations as are
specifically set forth in this Article, and no implied covenants or obligations
with respect to the holders of such Senior Indebtedness shall be read into this
Indenture against the Trustee.  Except with respect to Section 13.4, the Trustee
shall not be deemed to owe any fiduciary duty to the holders of Senior
Indebtedness and shall not be liable to any such holders or creditors if it
shall in good faith pay over or distribute to Holders of Convertible Debentures
or to the Company or to any other Person cash, property or securities to which
any holders of Senior Indebtedness shall be entitled by virtue of this Article
or otherwise.

     Section 13.13  Rights of Trustee as Holder of Senior Indebtedness;
Preservation of Trustee's Rights.  The Trustee in its individual capacity shall
be entitled to all the rights set forth in this Article with respect to any
Senior Indebtedness which may at any time be held by it, to the same extent as
any other holder of Senior Indebtedness and nothing in this Indenture shall
deprive the Trustee of any of its rights as such holder.

     Nothing in this Article XIII shall apply to claims of, or payments to, the
Trustee under or pursuant to Section 6.7 of this Indenture.

     Section 13.14  Article Applicable to Paying Agents.  In case at any time
any Paying Agent other than the Trustee shall have been appointed by the Company
and be then acting hereunder, the term "Trustee" as used in this Article shall
in such case (unless the context otherwise requires) be construed as extending
to and including such Paying Agent within its meaning as fully for all intents
and purposes as if such Paying Agent were named in this Article in addition to
or in place of the Trustee; provided, however, that Section 13.13 shall not
apply to the Company or any Affiliate of the Company if it or such Affiliate
acts as Paying Agent.

     Section 13.15  Certain Conversions Deemed Payment.  For purposes of this
Article only, (a) the issuance and delivery of junior securities (or cash paid
in lieu of fractional shares) upon conversion of Convertible Debentures in
accordance with Article XII shall not be deemed to constitute a payment or
distribution on account of the principal of or premium or interest on
Convertible Debentures or on account of the purchase or other acquisition of
Convertible Debentures, and (b) the payment, issuance or delivery of cash,
property or securities (other than junior securities and cash paid in lieu of
fractional shares) upon conversion of a Convertible Debenture shall be deemed to
constitute payment on account of the principal of such Convertible Debenture.
For the purposes of this Section, the term "junior securities" means (i) shares
of any stock of any class of the Company and (ii) securities of the Company
which are subordinated in right of payment to all Senior Indebtedness which may
be outstanding at the time of issuance or delivery of such securities to
substantially the same extent as, or to a greater extent than, the Convertible
Debentures are so subordinated as provided in this Article.  Nothing contained
in this Article or elsewhere in this Indenture or in the Convertible Debentures
is intended to or shall impair, as among the Company, its creditors other than
holders of Senior Indebtedness and the Holders of Convertible Debentures, the
right, which is absolute and unconditional, of the Holder of 

                                       72
<PAGE>
 
any Convertible Debenture to convert such Convertible Debenture in accordance
with Article XII.


                                  ARTICLE XIV

                                   EXPENSES

     Section 14.1  Payment of Expenses.  In connection with the offering, sale
and issuance of the Convertible Debentures to the Institutional Trustee and in
connection with the sale of the Trust  Securities by the Trust, the Company, in
its capacity as borrower with respect to the Convertible Debentures, shall:

          (a)  pay all costs and expenses relating to the offering, sale,
     issuance and registration under the Securities Act of the Convertible
     Debentures and the Trust Securities, including commissions to the
     purchasers payable pursuant to the Placement Agreement and compensation of
     the Trustee under this Indenture in accordance with the provisions of
     Section 6.7 of this Indenture;

          (b)  pay all costs and expenses of the Trust (including, but not
     limited to, costs and expenses relating to the organization of the Trust,
     the fees and expenses of the Institutional Trustee and the Delaware
     Trustee, the costs and expenses relating to the operation of the Trust,
     including without limitation, costs and expenses of accountants, attorneys,
     statistical or bookkeeping services, expenses for printing and engraving
     and computing or accounting equipment, paying agent(s), registrar(s),
     transfer agent(s), duplicating, travel and telephone and other
     telecommunications expenses and costs and expenses incurred in connection
     with the acquisition, financing, and disposition of Trust assets);

          (c)  pay all costs and expenses related to the enforcement by the
     Institutional Trustee of the rights of the holders of the Trust Securities;

          (d)  be primarily liable for any indemnification obligations arising
     with respect to the Declaration; and

          (e)  pay any and all taxes (other than United States withholding taxes
     attributable to the Trust or its assets) and all liabilities, costs and
     expenses with respect to such taxes of the Trust.

     Section 14.2  Payment Upon Resignation or Removal.  Upon termination of
this Indenture or the removal or resignation of the Trustee pursuant to Section
6.8 of this Indenture, the Company shall pay to the Trustee all amounts accrued
to the date of such termination, removal or resignation.  Upon termination of
the Declaration or the removal or resignation of the Delaware Trustee or the
Institutional Trustee, as the case may be, pursuant to Section 5.6 of the
Declaration, the Company shall pay to the Delaware Trustee or the 

                                       73
<PAGE>
 
Institutional Trustee, and their respective counsel, as the case may be, all
amounts accrued to the date of such termination, removal or resignation.


                                  ARTICLE XV

                           MISCELLANEOUS PROVISIONS

     Section 15.1  Incorporators, Stockholders, Officers and Directors of
Company Exempt from Individual Liability.  No recourse under or upon any
obligations, covenant or agreement contained in this Indenture, in any
Convertible Debenture, or because of any indebtedness evidenced thereby, shall
be had against any incorporator, as such or against any past, present or future
stockholder, officer or director, as such, of the Company or of any successor,
either directly or through the Company or any successor, under any rule of law,
statute or constitutional provision or by the enforcement of any assessment or
by any legal or equitable proceeding or otherwise, all such liability being
expressly waived and released by the acceptance of the Convertible Debentures by
the Holders thereof and as part of the consideration of the issue of the
Convertible Debentures.

     Section 15.2  Provisions of Indenture for the Sole Benefit of Parties and
Holders of Convertible Debentures.  Nothing in this Indenture or in the
Convertible Debentures, expressed or implied, shall give or be construed to give
to any Person, firm or corporation, other than the parties hereto, any Paying
Agent and their successors hereunder, the holders of Senior Indebtedness, the
holders of Convertible Preferred Securities (to the extent provided herein) and
the Holders of the Convertible Debentures any legal or equitable right, remedy
or claim under this Indenture or under any covenant or provision herein
contained, all such covenants and provisions being for the sole benefit of the
parties hereto and their successors and of the Holders of the Convertible
Debentures.

     Section 15.3  Right to Assign; Successors and Assigns Bound by Indenture.
The Company shall have the right at all times to assign any of its respective
rights or obligations under this Indenture to a direct or indirect wholly-owned
Subsidiary of the Company; provided that, in the event of any such assignment,
the Company shall remain liable for all of its obligations under this Indenture.
Subject to the foregoing, this Indenture will be binding upon and inure to the
benefit of the parties hereto and their respective successors and assigns.  The
rights and obligations of the parties under this Indenture may not otherwise be
assigned by such parties.

     All the covenants, stipulations, promises and agreements in this Indenture
by the parties hereto shall bind their respective successors and assigns,
whether so expressed or not.

     Section 15.4  Notices and Demands on Company, Trustee and Holders of
Convertible Debentures.  Any notice or demand which by any provision of this
Indenture is required or permitted to be given or served by the Trustee or by
the Holders of Convertible Debentures to or on the Company may be given or
served by being deposited postage prepaid, first-class mail (except as otherwise
specifically provided herein) addressed (until another address of the 

                                       74
<PAGE>
 
Company is filed by the Company with the Trustee) to McKesson Corporation,
McKesson Plaza, One Post Street, San Francisco, California 94104, Attention:
General Counsel. Any notice, direction, request or demand by the Company or any
Holder of Convertible Debentures to or upon the Trustee shall be deemed to have
been sufficiently given or made, for all purposes, if given or made at the
Corporate Trust Office.

     Where this Indenture provides for notice to Holders of Convertible
Debentures of any event such notice shall be sufficiently given (unless
otherwise herein expressly provided) if in writing and mailed by first-class
mail, postage prepaid to such Holders as their names and addresses appear in the
Convertible Debenture register within the time prescribed.  Where this Indenture
provides for notice in any manner, such notice may be waived in writing by the
Person entitled to receive such notice, either before or after the event, and
such waiver shall be the equivalent of such notice.  Waivers of notice by
Holders shall be filed with the Trustee, but such filing shall not be a
condition precedent to the validity of any action taken in reliance upon such
waiver. In any case where notice to Holders is given by mail, neither the
failure to mail such notice, nor any defect in any notice so mailed, shall
affect the sufficiency of such notice, and any notice which is mailed in the
manner herein provided shall be conclusively presumed to have been duly given.

     In case, by reason of the suspension of or irregularities in regular mail
service, it shall be impracticable to mail notice to the Company and Holders of
Convertible Debentures when such notice is required to be given pursuant to any
provision of this Indenture, then any manner of giving such notice as shall be
reasonably acceptable to the Trustee shall be deemed to be a sufficient giving
of such notice.

     Section 15.5  Officers' Certificates and Opinions of Counsel; Statements to
Be Contained Therein.  Upon any application or demand by the Company to the
Trustee to take action under any of the provisions of this Indenture, the
Company shall furnish to the Trustee an Officers' Certificate stating that all
conditions precedent, if any, provided for in this Indenture relating to the
proposed action have been complied with and an Opinion of Counsel stating that
in the opinion of such counsel all such conditions precedent, if any, have been
complied with, except that in the case of any such application or demand as to
which the furnishing of such documents is specifically required by any provision
of this Indenture relating to such particular application or demand, no
additional certificate or opinion need be furnished.

     Each certificate or opinion provided for in this Indenture and delivered to
the Trustee with respect to compliance with a condition or covenant provided for
in this Indenture shall include (a) a statement that the person making such
certificate or opinion has read such covenant or condition and the definitions
herein relating thereto, (b) a brief statement as to the nature and scope of the
examination or investigation upon which the statements or opinions contained in
such certificate or opinion are based, (c) a statement that, in the opinion of
such person, he has made such examination or investigation as is necessary to
enable him to express an informed opinion as to whether or not such covenant or
condition has been complied with and (d) a statement as to whether or not, in
the opinion of such person, such condition or covenant has been complied with.

                                       75
<PAGE>
 
     Any certificate, statement or opinion of any officer of the Company may be
based, insofar as it relates to legal matters, upon a certificate or opinion of
or representations by counsel, unless such officer knows that the certificate or
opinion or representations with respect to the matters upon which his
certificate, statement or opinion may be based as aforesaid are erroneous, or in
the exercise of reasonable care should know that the same are erroneous.  Any
certificate, statement or opinion of counsel may be based, insofar as it relates
to factual matters or information with respect to which is in the possession of
the Company, upon the certificate, statement or opinion of or representations by
an officer or officers of the Company, unless such counsel knows that the
certificate, statement or opinion or representations with respect to the matters
upon which his certificate, statement or opinion may be based as aforesaid are
erroneous, or in the exercise of reasonable care should know that the same are
erroneous.

     Any certificate, statement or opinion of an officer of the Company or of
counsel may be based, insofar as it relates to accounting matters, upon a
certificate or opinion of or representations by an accountant or firm of
accountants in the employ of the Company, unless such officer or counsel, as the
case may be, knows that the certificate or opinion or representations with
respect to the accounting matters upon which his certificate, statement or
opinion may be based as aforesaid are erroneous, or in the exercise of
reasonable care should know that the same are erroneous.

     Any certificate or opinion of any independent firm of public accountants
filed with and directed to the Trustee shall contain a statement that such firm
is independent.

     Section 15.6  Payments Due on Saturdays, Sundays and Holidays.  Except as
otherwise provided in Section 2.5, if the date of Maturity of interest on or
principal of the Convertible Debentures or the date fixed for redemption or
repayment of any such Convertible Debenture shall not be a Business Day, then
payment of interest or principal need not be made on such date, but may be made
on the next succeeding Business Day; provided that if such next succeeding
Business Day falls in the next succeeding calendar year, such payment shall be
made on the immediately preceding Business Day, in each case with the same force
and effect as if made on the date of Maturity or the date fixed for redemption,
and no interest shall accrue for the period after such date.

     Section 15.7  Conflict of Any Provision of Indenture with Trust Indenture
Act.  If and to the extent that any provision of this Indenture limits,
qualifies or conflicts with another provision included in this Indenture which
is required by the Trust Indenture Act, such required provision shall control.

     Section 15.8  New York Law to Govern.  THIS INDENTURE AND THE CONVERTIBLE
DEBENTURES SHALL BE DEEMED TO BE CONTRACTS MADE AND TO BE PERFORMED ENTIRELY IN
THE STATE OF NEW YORK, AND FOR ALL PURPOSES SHALL BE GOVERNED BY AND CONSTRUED
IN ACCORDANCE WITH THE LAWS OF SAID STATE WITHOUT REGARD TO THE CONFLICTS OF LAW
RULES OF SAID STATE.

                                       76
<PAGE>
 
     Section 15.9  Counterparts.  This Indenture may be executed in any number
of counterparts, each of which shall be an original; but such counterparts shall
together constitute but one and the same instrument.

     Section 15.10  Effect of Headings; Gender.  The Article and Section
headings herein and the Table of Contents are for convenience only and shall not
affect the construction hereof.  The use of the masculine, feminine or neuter
gender herein shall not limit in any way the applicability of any term or
provision hereof.

                                       77
<PAGE>
 
     IN WITNESS WHEREOF, the parties hereto have caused this Indenture to be
duly executed, and their respective corporate seals to be hereto affixed and
attested, all as of the day and year first above written.

                                        McKESSON CORPORATION



                                        By:  /s/ Ivan D. Meyerson
                                             --------------------------
                                             Name:  Ivan D. Meyerson
                                             Title: Vice President


                                        THE FIRST NATIONAL BANK OF CHICAGO, 
                                        as Trustee



                                        By:  /s/ Richard D. Manella
                                             --------------------------
                                             Name:  Richard D. Manella
                                             Title: Vice President

                                       78
<PAGE>
 
                                                                       EXHIBIT A


                   [(FORM OF FACE OF CONVERTIBLE DEBENTURE)]


     [IF THE DEBENTURE IS TO BE A GLOBAL DEBENTURE, INSERT THE FOLLOWING - -
THIS DEBENTURE IS A BOOK-ENTRY DEBENTURE WITHIN THE MEANING OF THE INDENTURE
HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITARY OR A
NOMINEE OF A DEPOSITARY.  THIS DEBENTURE IS EXCHANGEABLE FOR CONVERTIBLE
DEBENTURES REGISTERED IN THE NAME OF A PERSON OTHER THAN THE DEPOSITARY OR ITS
NOMINEE ONLY IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE INDENTURE, AND NO
TRANSFER OF THIS DEBENTURE (OTHER THAN A TRANSFER OF THIS DEBENTURE AS A WHOLE
BY THE DEPOSITARY TO A NOMINEE OF THE DEPOSITARY OR BY A NOMINEE OF THE
DEPOSITARY TO THE DEPOSITARY OR ANOTHER NOMINEE OF THE DEPOSITARY) MAY BE
REGISTERED EXCEPT IN SUCH LIMITED CIRCUMSTANCES.

     UNLESS THIS DEBENTURE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY (55 WATER STREET, NEW YORK, NEW YORK) TO THE ISSUER OR
ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY DEBENTURE
ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED
BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT
HEREON IS MADE TO CEDE & CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE
OR OTHERWISE BY A PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE &
CO., HAS AN INTEREST HEREIN.]

No. __________                                              CUSIP NO. __________

                             MCKESSON CORPORATION

                 5% CONVERTIBLE JUNIOR SUBORDINATED DEBENTURE

[PRIOR TO THE TRANSFER RESTRICTION TERMINATION DATE, ANY CERTIFICATE EVIDENCING
A CONVERTIBLE DEBENTURE SHALL BEAR A LEGEND IN SUBSTANTIALLY THE FOLLOWING FORM,
UNLESS OTHERWISE AGREED BY THE COMPANY (WITH WRITTEN NOTICE THEREOF TO THE
TRUSTEE):  THE SECURITY EVIDENCED HEREBY HAS NOT BEEN REGISTERED UNDER THE U.S.
SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND, ACCORDINGLY, MAY
NOT BE OFFERED OR SOLD WITHIN THE UNITED STATES OR TO, OR FOR THE ACCOUNT OR
BENEFIT OF, U.S. PERSONS EXCEPT AS SET FORTH IN THE FOLLOWING SENTENCE.  BY ITS
ACQUISITION HEREOF, THE HOLDER (1) REPRESENTS THAT (A) IT IS A "QUALIFIED

                                      A-1
<PAGE>
 
INSTITUTIONAL BUYER" (AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT) OR (B)
IT IS AN INSTITUTIONAL "ACCREDITED INVESTOR" (AS DEFINED IN RULE 501(A)(1), (2),
(3) OR (7) UNDER THE SECURITIES ACT) ("INSTITUTIONAL ACCREDITED INVESTOR") OR
(C) IT IS NOT A U.S. PERSON AND IS ACQUIRING THE SECURITY EVIDENCED HEREBY IN AN
OFFSHORE TRANSACTION, (2) AGREES THAT IT WILL NOT PRIOR TO THE EXPIRATION OF THE
HOLDING PERIOD APPLICABLE TO SALES OF THE SECURITY EVIDENCED HEREBY UNDER RULE
144(K) UNDER THE SECURITIES ACT (OR ANY SUCCESSOR PROVISION), RESELL OR
OTHERWISE TRANSFER THE SECURITY EVIDENCED HEREBY OR, IF THIS SECURITY IS
CONVERTIBLE INTO COMMON STOCK, THE COMMON STOCK ISSUABLE UPON CONVERSION OR
EXCHANGE OF THIS SECURITY EXCEPT (A) TO McKESSON CORPORATION (THE "COMPANY") OR
ANY SUBSIDIARY THEREOF, (B) PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT
UNDER THE SECURITIES ACT, (C) TO A QUALIFIED INSTITUTIONAL BUYER IN COMPLIANCE
WITH RULE 144A UNDER THE SECURITIES ACT, (D) TO AN INSTITUTIONAL ACCREDITED
INVESTOR THAT, PRIOR TO SUCH TRANSFER, FURNISHES TO THE TRUSTEE FOR THE
CONVERTIBLE PREFERRED SECURITIES OR THE CONVERTIBLE DEBENTURES, AS THE CASE MAY
BE (OR, IF THIS CERTIFICATE EVIDENCES COMMON STOCK, THE TRANSFER AGENT FOR THE
COMMON STOCK), A SIGNED LETTER CONTAINING CERTAIN REPRESENTATIONS AND AGREEMENTS
RELATING TO THE RESTRICTIONS ON TRANSFER OF THE SECURITY EVIDENCED HEREBY (THE
FORM OF WHICH LETTER CAN BE OBTAINED FROM SUCH TRUSTEE OR TRANSFER AGENT), (E)
OUTSIDE THE UNITED STATES IN COMPLIANCE WITH RULE 904 UNDER THE SECURITIES ACT
OR (F) PURSUANT TO THE EXEMPTION FROM REGISTRATION PROVIDED BY RULE 144 UNDER
THE SECURITIES ACT (IF AVAILABLE) AND (3) AGREES THAT IT WILL DELIVER TO EACH
PERSON TO WHOM THE SECURITY EVIDENCED HEREBY IS TRANSFERRED A NOTICE
SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND.  IN CONNECTION WITH ANY TRANSFER OF
THE SECURITY EVIDENCED HEREBY PRIOR TO THE EXPIRATION OF THE HOLDING PERIOD
APPLICABLE TO SALES OF THE SECURITY EVIDENCED HEREBY UNDER RULE 144(K) UNDER THE
SECURITIES ACT (OR ANY SUCCESSOR PROVISION), THE HOLDER MUST CHECK THE
APPROPRIATE BOX SET FORTH ON THE REVERSE HEREOF RELATING TO THE MANNER OF SUCH
TRANSFER AND SUBMIT THIS CERTIFICATE TO THE TRUSTEE FOR THE CONVERTIBLE
PREFERRED SECURITIES OR THE CONVERTIBLE DEBENTURES, AS THE CASE MAY BE (OR, IF
THIS CERTIFICATE EVIDENCES COMMON STOCK, SUCH HOLDER MUST FURNISH TO THE
TRANSFER AGENT SUCH CERTIFICATIONS, LEGAL OPINIONS OR OTHER INFORMATION AS THE
COMPANY OR McKESSON FINANCING TRUST (THE "TRUST") MAY REASONABLY REQUIRE TO
CONFIRM THAT SUCH TRANSFER IS BEING MADE PURSUANT TO AN EXEMPTION FROM, OR IN A
TRANSACTION NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE SECURITIES
ACT).  IF THIS CERTIFICATE DOES NOT EVIDENCE COMMON STOCK AND IF THE PROPOSED
TRANSFEREE IS AN INSTITUTIONAL ACCREDITED INVESTOR OR A PURCHASER WHO IS NOT A
U.S. PERSON, THE HOLDER MUST, PRIOR TO 

                                      A-2
<PAGE>
 
SUCH TRANSFER, FURNISH TO THE TRUSTEE FOR THE CONVERTIBLE PREFERRED SECURITIES
OR THE CONVERTIBLE DEBENTURES, AS THE CASE MAY BE, SUCH CERTIFICATIONS, LEGAL
OPINIONS OR OTHER INFORMATION AS THE COMPANY OR THE TRUST MAY REASONABLY REQUIRE
TO CONFIRM THAT SUCH TRANSFER IS BEING MADE PURSUANT TO AN EXEMPTION FROM, OR IN
A TRANSACTION NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE SECURITIES
ACT. THIS LEGEND WILL BE REMOVED AFTER THE EXPIRATION OF THE HOLDING PERIOD
APPLICABLE TO SALES OF THE SECURITY EVIDENCED HEREBY UNDER RULE 144(K) UNDER THE
SECURITIES ACT. AS USED HEREIN, THE TERMS "OFFSHORE TRANSACTION," "UNITED
STATES" AND "U.S. PERSON" HAVE THE MEANINGS GIVEN TO THEM BY REGULATION S UNDER
THE SECURITIES ACT.]

     McKesson Corporation, a Delaware corporation (the "Company", which term
includes any successor corporation under the Indenture hereinafter referred to),
for value received, hereby promises to pay to, The First National Bank of
Chicago, as Institutional Trustee (the "Institutional Trustee") for McKesson
Financing Trust or registered assigns, the principal sum of [Two Hundred Six
Million One Hundred Eighty-Six Thousand Dollars ($206,186,000)]/1/ on June 1,
2027 and to pay interest on said principal sum from February 20, 1997, or from
the most recent interest payment date to which interest has been paid or duly
provided for, quarterly (subject to deferral as set forth herein) in arrears on
March 1, June 1, September 1, and December 1 (each such date, an "Interest
Payment Date") of each year commencing June 1, 1997, at the rate of 5% per annum
until the principal hereof shall have become due and payable, and on any overdue
principal and premium, if any, and (without duplication and to the extent that
payment of such interest is enforceable under applicable law) on any overdue
installment of interest at the same rate per annum compounded quarterly.  The
amount of interest payable on any Interest Payment Date shall be computed on the
basis of a 360-day year of twelve 30-day months.  The amount of interest payable
for any period shorter than a full quarterly period for which interest is
computed, will be computed on the basis of the actual number of days elapsed per
30-day month.  In the event that any date on which interest is payable on this
Convertible Debenture is not a Business Day, then payment of interest payable on
such date will be made on the next succeeding day that is a Business Day (and
without any interest or other payment in respect of any such delay), except
that, if such Business Day is in the next succeeding calendar year, such payment
shall be made on the immediately preceding Business Day, in each case with the
same force and effect as if made on such date.  The interest installment so
payable, and punctually paid or duly provided for, on any Interest Payment Date
will, as provided in the Indenture (referred to on the reverse hereof) be paid
to the person in whose name this Convertible Debenture (or one or more
Predecessor Convertible Debentures, as defined in said Indenture) is registered
on the record date for such interest installment, which shall be the close of
business on the fifteenth day prior to such Interest Payment Date.  Any such
interest installment not punctually paid or duly provided for shall forthwith
cease to be 

_____________________
     /1/ In the case of a Global Debenture the bracketed text will be replaced 
with the following: "principal amount set forth on Schedule A hereto".

                                      A-3
<PAGE>
 
payable to the registered Holders on such record date and may be paid to the
Person in whose name this Convertible Debenture (or one or more Predecessor
Convertible Debentures) is registered at the close of business on a special
record date to be fixed by the Trustee for the payment of such defaulted
interest, notice whereof shall be given to the registered Holders of the
Convertible Debentures not less than 10 days prior to such special record date,
or may be paid at any time in any other lawful manner not inconsistent with the
requirements of any securities exchange on which the Convertible Debentures may
be listed, and upon such notice as may be required by such exchange, all as more
fully provided in the Indenture. The principal of (and premium, if any) and the
interest on this Convertible Debenture shall be payable at the office or agency
of the Trustee maintained for that purpose in any coin or currency of the United
States of America that at the time of payment is legal tender for payment of
public and private debts; provided, however, that payment of interest may be
made at the option of the Company by check mailed to the registered Holder at
such address as shall appear in the Security Register. Notwith standing the
foregoing, so long as the Holder of this Convertible Debenture is the
Institutional Trustee, the payment of the principal of (and premium, if any) and
interest on this Convertible Debenture will be made at such place and to such
account as may be designated by the Institutional Trustee.

     The indebtedness evidenced by this Convertible Debenture is, to the extent
provided in the Indenture, subordinate and junior in right of payment to the
prior payment in full of all Senior Indebtedness, and this Convertible Debenture
is issued subject to the provisions of the Indenture with respect thereto.  Each
Holder of this Convertible Debenture, by accepting the same, (a) agrees to and
shall be bound by such provisions, (b) authorizes and directs the Trustee on his
or her behalf to take such action as may be necessary or appropriate to
acknowledge or effectuate the subordination so provided and (c) appoints the
Trustee his or her attorney-in-fact for any and all such purposes.  Each Holder
hereof, by his or her acceptance hereof, hereby waives all notice of the
acceptance of the subordination provisions contained herein and in the Indenture
by each holder of Senior Indebtedness, whether now outstanding or hereafter
incurred, and waives reliance by each such holder upon said provisions.

     This Convertible Debenture shall not be entitled to any benefit under the
Indenture hereinafter referred to, be valid or become obligatory for any purpose
until the Certificate of Authentication hereon shall have been signed by or on
behalf of the Trustee.

     The provisions of this Convertible Debenture are continued on the reverse
side hereof and such continued provisions shall for all purposes have the same
effect as though fully set forth at this place.

     Capitalized terms used but not defined herein shall have the meaning given
them in the Indenture.

                                      A-4
<PAGE>
 
     IN WITNESS WHEREOF, the Company has caused this instrument to be executed.

                                        McKESSON CORPORATION


                                        By: ____________________________________
                                            Name:
                                            Title:

Attest:


By: ________________________________
    Name:
    Title:

                                      A-5
<PAGE>
 
                    [FORM OF CERTIFICATE OF AUTHENTICATION]

                         CERTIFICATE OF AUTHENTICATION

     This is one of the Convertible Debentures described in the within-mentioned
Indenture.

Dated:

THE FIRST NATIONAL BANK OF CHICAGO
as Trustee


By: ________________________________
    Authorized Signatory

                                      A-6
<PAGE>
 
                        [FORM OF REVERSE OF DEBENTURE]

     This Convertible Debenture is one of the 5% Convertible Junior Subordinated
Debentures (herein referred to as the "Convertible Debentures"), all issued or
to be issued under and pursuant to an Indenture dated as of February 20, 1997,
duly executed and delivered between the Company and The First National Bank of
Chicago, as Trustee (the "Trustee") (the "Indenture"), to which Indenture and
all indentures supplemental thereto reference is hereby made for a description
of the rights, limitations of rights, obligations, duties and immunities
thereunder of the Trustee, the Company and the Holders of the Convertible
Debentures.  The Convertible Debentures are limited in aggregate principal
amount as specified in the Indenture.

     Because of the occurrence and continuation of a Tax Event, in certain
circumstances, this Convertible Debenture may become due and payable at the
principal amount specified on the face hereof together with any interest accrued
thereon (the "Redemption Price").  The Redemption Price shall be paid prior to
12:00 noon, New York City time, on the date of such redemption or at such
earlier time as the Company determines.  The Company shall have the right to
redeem this Convertible Debenture at the option of the Company, upon not less
than 30 nor more than 60 days notice, without premium or penalty, in whole or in
part at any time on or after March 4, 2000 (an "Optional Redemption") at the
following prices (expressed as percentages of the principal amount of the
Convertible Debentures) (the "Optional Redemption Price") together with accrued
and unpaid interest (including Additional Sums, if any, and, to the extent
permitted by applicable law, Compound Interest, if any) to, but excluding, the
redemption date, if redeemed during the 12-month period beginning March 4 of the
applicable year set forth below:

<TABLE>
<CAPTION>
                     Year   Redemption Price
                    ------  -----------------
                    <S>     <C>
                     2000        103.500%
                     2001        103.000%
                     2002        102.500%
                     2003        102.000%
                     2004        101.500%
                     2005        101.000%
                     2006        100.500%
</TABLE>

and 100% if redeemed on or after March 4, 2007.

     If Convertible Debentures are redeemed on any March 1, June 1, September 1,
or December 1, accrued and unpaid interest shall be payable to holders of record
on the relevant record date.

     So long as the corresponding Trust Securities are outstanding, the proceeds
from the redemption of any of the Convertible Debentures will be used to redeem
Trust Securities.

                                      A-7
<PAGE>
 
     If the Convertible Debentures are only partially redeemed by the Company
pursuant to an Optional Redemption, the Convertible Debentures will be redeemed
pro rata;

     In the event of redemption of this Convertible Debenture in part only, a
new Convertible Debenture or Convertible Debentures for the unredeemed portion
hereof will be issued in the name of the Holder hereof upon the cancellation
hereof.

     In case an Event of Default, as defined in the Indenture, shall have
occurred and be continuing, the principal of all of the Convertible Debentures
and the interest accrued thereon may be declared, and upon such declaration
shall become, due and payable, in the manner, with the effect and subject to the
conditions provided in the Indenture.

     The Indenture contains provisions permitting the Company and the Trustee,
with the consent of the Holders of a majority of the aggregate principal amount
of the Convertible Debentures at the time Outstanding, evidenced as provided in
the Indenture, to execute supplemental indentures adding any provisions to or
changing in any manner or eliminating any of the provisions of the Indenture or
of any supplemental indenture or modifying in any manner the rights of the
Holders of the Convertible Debentures; provided, however, that no such
supplemental indenture shall (i) extend the Stated Maturity of any Convertible
Debenture, or reduce the principal amount thereof or any premium thereon, or
reduce the rate or extend the time of payment of interest thereon, or reduce any
amount payable upon redemption thereof, or impair or affect the right of any
Holder to institute suit for the payment thereof, without the consent of the
Holder of each Convertible Debenture so affected, or (ii) reduce the aforesaid
percentage of Convertible Debentures, the Holders of which are required to
consent to any such supplemental indenture, without the consent of the Holder of
each Convertible Debenture.  It is also provided in the Indenture that, with
respect to certain defaults or Events of Default regarding the Convertible
Debentures, prior to any declaration accelerating the maturity of such
Convertible Debentures, the Holders of a majority in aggregate principal amount
Outstanding of the Convertible Debentures (or, in the case of certain defaults
or Events of Default, all of the Convertible Debentures), may on behalf of the
Holders of all the Convertible Debentures waive any such past default or Event
of Default and its consequences.  The preceding sentence shall not , however,
apply to a default in the payment of the principal of or premium, if any, or
interest on any of the Convertible Debentures.  Any such consent or waiver by
the Holder of this Convertible Debenture (unless revoked as provided in the
Indenture) shall be conclusive and binding upon such Holder and upon all future
Holders and owners of this Convertible Debenture and any Convertible Debenture
which may be issued in exchange or substitution therefor, irrespective of
whether or not any notation thereof is made upon this Convertible Debenture or
such other Convertible Debenture.

     No reference herein to the Indenture and no provision of this Convertible
Debenture or of the Indenture shall alter or impair the obligation of the
Company, which is absolute and unconditional, to pay the principal of and
premium, if any, and interest on this Convertible Debenture at the time and
place and at the rate and in the money herein prescribed.

                                      A-8
<PAGE>
 
     As long as an Event of Default under Section 5.1(a) of the Indenture shall
not have occurred and be continuing, the Company shall have the right at any
time during the term of the Convertible Debentures and from time to time to
extend the interest payment period of such Convertible Debentures for up to 20
consecutive quarters (an "Extension Period"), at the end of which period the
Company shall pay all interest then accrued and unpaid (together with interest
thereon at the rate specified for the Convertible Debentures to the extent that
payment of such interest is enforceable under applicable law).  Before the
termination of any such Extension Period, the Company may further extend such
Extension Period, provided that such Extension Period together with all such
further extensions thereof shall not exceed 20 consecutive quarters.  At the
termination of any such Extension Period and upon the payment of all accrued and
unpaid interest and any additional amounts then due, the Company may commence a
new Extension Period.

     As provided in the Indenture and subject to certain limitations therein set
forth, this Convertible Debenture is transferable by the registered Holder
hereof on the Security Register of the Company, upon surrender of this
Convertible Debenture for registration of transfer at the office or agency of
the Trustee in the City and State of New York accompanied by a written
instrument or instruments of transfer in form satisfactory to the Company or the
Trustee duly executed by the registered Holder hereof or his attorney duly
authorized in writing, and thereupon one or more new Convertible Debentures of
authorized denominations and for the same aggregate principal amount will be
issued to the designated transferee or transferees.  No service charge will be
made for any such transfer, but the Company may require payment of a sum
sufficient to cover any tax or other governmental charge payable in relation
thereto.

     Prior to due presentment for registration of transfer of this Convertible
Debenture, the Company, the Trustee, any paying agent and the Registrar may deem
and treat the registered holder hereof as the absolute owner hereof (whether or
not this Convertible Debenture shall be overdue and notwithstanding any notice
of ownership or writing hereon made by anyone other than the Registrar) for the
purpose of receiving payment of or on account of the principal hereof and
premium, if any, and interest due hereon and for all other purposes, and neither
the Company nor the Trustee nor any paying agent nor any Registrar shall be
affected by any notice to the contrary.

     No recourse shall be had for the payment of the principal of or the
interest on this Convertible Debenture, or for any claim based hereon, or
otherwise in respect hereof, or based on or in respect of the Indenture, against
any incorporator, stockholder, officer or director, past, present or future, as
such, of the Company or of any predecessor or successor corporation, whether by
virtue of any constitution, statute or rule of law, or by the enforcement of any
assessment or penalty or otherwise, all such liability being, by the acceptance
hereof and as part of the consideration for the issuance hereof, expressly
waived and released.

     The Holder of any Convertible Debenture has the right, exercisable at any
time beginning May 21, 1997 through the close of business (New York time) on May
28, 2027 (or, in the case of a Convertible Debenture called for redemption,
prior to the close of business on the Business Day prior to the corresponding
redemption date), to convert the principal amount thereof (or any portion
thereof that is an integral multiple of $50) into shares of Common Stock at the
initial

                                      A-9
<PAGE>
 
conversion rate of .6709 shares of Common Stock for each Convertible Debenture
(equivalent to a Conversion Price of $74.53 per share of Common Stock), subject
to adjustment under certain circumstances.

     To convert a Convertible Debenture, a Holder must (a) complete and sign a
conversion notice substantially in the form attached hereto, (b) surrender the
Convertible Debenture to a Conversion Agent, (c) furnish appropriate
endorsements or transfer documents if required by the Conversion Agent and (d)
pay any transfer or similar tax, if required.  Upon conversion, no adjustment or
payment will be made for interest or dividends, but if any Holder surrenders a
Convertible Debenture for conversion on or after the record date for the payment
of an installment of interest and prior to the opening of business on the next
Interest Payment Date, then, notwithstanding such conversion, the interest
payable on such Interest Payment Date will be paid to the registered Holder of
such Convertible Debenture on such record date.  In such event, such Convertible
Debenture, when surrendered for conversion, need not be accompanied by payment
of an amount equal to the interest payable on such Interest Payment Date on the
portion so converted.  However, if a redemption date falls between a record date
and the subsequent Interest Payment Date, the Holder will be entitled to
receive, on such redemption date, the interest accrued to, but excluding, the
redemption date.  The number of shares issuable upon conversion of a Convertible
Debenture is determined by dividing the principal amount of the Convertible
Debenture converted by the Conversion Price in effect on the Conversion Date.
No fractional shares will be issued upon conversion but a cash adjustment will
be made for any fractional interest.  The outstanding principal amount of any
Convertible Debenture shall be reduced by the portion of the principal amount
thereof converted into shares of Common Stock.

     The Convertible Debentures are issuable only in registered form without
coupons in denominations of $50 and any integral multiple thereof./2/ This
Global Debenture is exchangeable for Convertible Debentures in definitive form
only under certain limited circumstances set forth in the Indenture.
Convertible Debentures so issued are issuable only in registered form without
coupons in denominations of $50 and any integral multiple thereof./3/ As
provided in the Indenture and subject to certain limitations therein set forth,
Convertible Debentures are exchangeable for a like aggregate principal amount of
Convertible Debentures of a different authorized denomination, as requested by
the Holder surrendering the same.



     THE INDENTURE AND THE CONVERTIBLE DEBENTURES SHALL BE DEEMED TO BE
CONTRACTS MADE AND TO BE PERFORMED ENTIRELY IN THE STATE OF NEW YORK, AND FOR
ALL PURPOSES SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF
SAID STATE WITHOUT REGARD TO THE CONFLICTS OF LAW RULES OF SAID STATE.



______________________
     /2/  This text will appear in the case of registered definitive
certificates issued to Institutional Accredited Investors.

     /3/  This text will appear in the case of a Global Debenture.

                                   A-10     
<PAGE>
 
                         [FORM OF ELECTION TO CONVERT]
                              ELECTION TO CONVERT

To:  McKesson Corporation

     The undersigned owner of this Convertible Debenture hereby irrevocably
exercises the option to convert this Convertible Debenture, or the portion below
designated, into Common Stock of McKESSON CORPORATION in accordance with the
terms of the Indenture referred to in this Convertible Debenture, and directs
that the shares issuable and deliverable upon conversion, together with any
check in payment for fractional shares, be issued in the name of and delivered
to the undersigned, unless a different name has been indicated in the assignment
below.  If shares are to be issued in the name of a person other than the
undersigned, the undersigned will pay all transfer taxes payable with respect
thereto.

Date:  _______________, ____

       in whole _____      Portions of Convertible Debenture to be converted
                           ($50 or integral multiples-thereof):$________________

                           _____________________________________________________
                           Signature (for conversion only)

                           Please Print or Typewrite Name and Address, Including
                           Zip Code, and Social Security or Other Identifying
                           Number
                           
                           _____________________________________________________
                           _____________________________________________________
                           _____________________________________________________
 
                           Signature Guarantee:/4/ _____________________________




___________________
/4/  Signature must be guaranteed by an "eligible guarantor institution" that is
a bank, stockbroker, savings and loan association or credit union meeting the
requirements of the Conversion Agent, which requirements include membership or
participation in the Securities Transfer Agents Medallion Program ("STAMP") or
such other "signature guarantee program" as may be determined by the Conversion
Agent in addition to, or in substitution for, STAMP, all in accordance with the
Securities Exchange Act of 1934, as amended.

                                     A-11
<PAGE>
 
                                  ASSIGNMENT

                [FORM OF ASSIGNMENT FOR CONVERTIBLE DEBENTURES
                        THAT ARE NOT GLOBAL DEBENTURES]

For value received__________________________ hereby sell(s), assign(s) and
transfer(s) unto _______________________________________________________________
   (Please insert social security or other taxpayer identification number of
                                  assignee.)

the within Convertible Debenture and hereby irrevocably constitutes and appoints
_______ attorney to transfer the said Convertible Debenture on the books of the
Company, with full power of substitution in the premises.

In connection with any transfer of the within Convertible Debenture occurring
prior to the Transfer Restriction Termination Date, the undersigned confirms
that such Convertible Debenture is being transferred:

     [_]  To McKesson Corporation or a subsidiary thereof; or

     [_]  Pursuant to and in compliance with Rule 144A under the Securities Act
          of 1933, as amended; or

     [_]  To an Institutional Accredited Investor pursuant to and in compliance
          with the Securities Act of 1933, as amended; or

     [_]  Pursuant to and in compliance with Regulation S under the Securities
          Act of 1933, as amended; or

     [_]  Pursuant to and in compliance with Rule 144 under the Securities Act
          of 1933, as amended; or

     [_]  Pursuant to an effective registration statement.

                                     A-12
<PAGE>
 
and unless the box below is checked, the undersigned confirms that such
Convertible Debenture is not being transferred to an "affiliate" of the Company
as defined in Rule 144 under the Securities Act of 1933, as amended (an
"Affiliate"):

     [_]  The transferee is an Affiliate of the Company.


Dated: _____________________________


                                                   _____________________________



                                                   _____________________________
                                                            Signature(s)


____________________________________
       Signature Guarantee /5/

NOTICE:  The above signatures of the holder(s) hereof must correspond with the
name as written upon the face of this Convertible Debenture in every particular
without alteration or enlargement or any change whatever.





____________________
     /5/  (Signature must be guaranteed by an "eligible guarantor institution," 
that is, a bank, stockbroker, savings and loan association or credit union
meeting the requirements of the Registrar, which requirements include membership
or participation in the Securities Transfer Agents Medallion Program ("STAMP")
or such other "signature guarantee program" as may be determined by the
Registrar in addition to, or in substitution for, STAMP, all in accordance with
the Securities Exchange Act of 1934, as amended.)

                                     A-13
<PAGE>
 
            [FORM OF SCHEDULE FOR ENDORSEMENTS ON GLOBAL DEBENTURES
                    TO REFLECT CHANGES IN PRINCIPAL AMOUNT]

                                  Schedule A

               Changes to Principal Amount of Global Debentures

          Principal Amount of          
        Convertible Debentures    
         by which this Global  
          Debenture is to be                       
        Reduced or Increased,     Remaining Principal             
           and Reason for            Amount of this    
 Date   Reduction or Increase       Global Debenture     Notation Made By 
- - ------ -----------------------   ---------------------  ------------------   
                                      
                                     A-14 
 

<PAGE>
 
                                                                     Exhibit 4.7
                                                                     -----------

________________________________________________________________________________


                    PREFERRED SECURITIES GUARANTEE AGREEMENT



                            MCKESSON FINANCING TRUST






                         Dated as of February 20, 1997


________________________________________________________________________________
<PAGE>
 
                               TABLE OF CONTENTS

<TABLE> 
<CAPTION> 
                                                                                      Page
                                                                                      ----
                                   ARTICLE I

                         DEFINITIONS AND INTERPRETATION
 <S>                                                                                  <C>
 SECTION 1.1  Definitions and Interpretation..........................................  1


                                   ARTICLE II

                              TRUST INDENTURE ACT

 SECTION 2.1  Trust Indenture Act; Application........................................  4
 SECTION 2.2  Lists of Holders........................................................  4
 SECTION 2.3  Reports by the Preferred Guarantee Trustee..............................  4
 SECTION 2.4  Periodic Reports to Preferred Guarantee Trustee.........................  5
 SECTION 2.5  Evidence of Compliance with Conditions Precedent........................  5
 SECTION 2.6  Events of Default; Waiver...............................................  5
 SECTION 2.7  Event of Default; Notice................................................  5
 SECTION 2.8  Conflicting Interests...................................................  6

                                  ARTICLE III

            POWERS, DUTIES AND RIGHTS OF PREFERRED GUARANTEE TRUSTEE

 SECTION 3.1  Powers and Duties of the Preferred Guarantee Trustee....................  6
 SECTION 3.2  Certain Rights of Preferred Guarantee Trustee...........................  7
 SECTION 3.3  Not Responsible for Recitals or Issuance of Preferred Securities
              Guarantee...............................................................  9

                                   ARTICLE IV

                          PREFERRED GUARANTEE TRUSTEE

 SECTION 4.1  Preferred Guarantee Trustee: Eligibility................................ 10
 SECTION 4.2  Appointment, Removal and Resignation of Preferred
              Guarantee Trustee....................................................... 10
</TABLE>

                                       i
<PAGE>
 
<TABLE> 
                                   ARTICLE V

                                   GUARANTEE
 <S>                                                             <C>
 SECTION 5.1  Guarantee........................................  11
 SECTION 5.2  Waiver of Notice and Demand......................  11
 SECTION 5.3  Obligations Not Affected.........................  12
 SECTION 5.4  Rights of Holders................................  12
 SECTION 5.5  Guarantee of Payment.............................  13
 SECTION 5.6  Subrogation......................................  13
 SECTION 5.7  Independent Obligations..........................  13


                                   ARTICLE VI

                   LIMITATION OF TRANSACTIONS; SUBORDINATION

 SECTION 6.1  Limitation of Transactions.......................  13
 SECTION 6.2  Subordination....................................  14


                                  ARTICLE VII

                                  TERMINATION

 SECTION 7.1  Termination......................................  14


                                 ARTICLE VIII

                                INDEMNIFICATION

 SECTION 8.1  Exculpation......................................  15
 SECTION 8.2  Indemnification..................................  15


                                  ARTICLE IX

                                 MISCELLANEOUS


 SECTION 9.1  Successors and Assigns...........................  16
 SECTION 9.2  Amendments.......................................  16
 SECTION 9.3  Notices..........................................  16
 SECTION 9.4  Benefit..........................................  17
 SECTION 9.5  Governing Law....................................  17
</TABLE>

                                      ii
<PAGE>
 
[PRIOR TO THE TRANSFER RESTRICTION TERMINATION DATE (AS DEFINED IN THE
DECLARATION), ANY CERTIFICATE EVIDENCING THIS PREFERRED SECURITIES GUARANTEE
SHALL BEAR A LEGEND IN SUBSTANTIALLY THE FOLLOWING FORM, UNLESS OTHERWISE AGREED
BY THE REGULAR TRUSTEES (WITH WRITTEN NOTICE TO THE INSTITUTIONAL TRUSTEE)
PURSUANT TO SECTION 9.1(D) OF THE DECLARATION:

THE SECURITY EVIDENCED HEREBY HAS NOT BEEN REGISTERED UNDER THE U.S. SECURITIES
ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND, ACCORDINGLY, MAY NOT BE
OFFERED OR SOLD WITHIN THE UNITED STATES OR TO, OR FOR THE ACCOUNT OR BENEFIT
OF, U.S. PERSONS EXCEPT AS SET FORTH IN THE FOLLOWING SENTENCE.  BY ITS
ACQUISITION HEREOF, THE HOLDER (1) REPRESENTS THAT (A) IT IS A "QUALIFIED
INSTITUTIONAL BUYER" (AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT) OR (B)
IT IS AN INSTITUTIONAL "ACCREDITED INVESTOR" (AS DEFINED IN RULE 501(A)(1), (2),
(3) OR (7) UNDER THE SECURITIES ACT) ("INSTITUTIONAL ACCREDITED INVESTOR") OR
(C) IT IS NOT A U.S. PERSON AND IS ACQUIRING THE SECURITY EVIDENCED HEREBY IN AN
OFFSHORE TRANSACTION, (2) AGREES THAT IT WILL NOT PRIOR TO THE EXPIRATION OF THE
HOLDING PERIOD APPLICABLE TO SALES OF THE SECURITY EVIDENCED HEREBY UNDER RULE
144(K) UNDER THE SECURITIES ACT (OR ANY SUCCESSOR PROVISION) RESELL OR OTHERWISE
TRANSFER THE SECURITY EVIDENCED HEREBY OR THE COMMON STOCK ISSUABLE UPON
CONVERSION OR EXCHANGE OF THIS SECURITY EXCEPT (A) TO McKESSON CORPORATION (THE
"COMPANY") OR ANY SUBSIDIARY THEREOF, (B) PURSUANT TO AN EFFECTIVE REGISTRATION
STATEMENT UNDER THE SECURITIES ACT, (C) TO A QUALIFIED INSTITUTIONAL BUYER IN
COMPLIANCE WITH RULE 144A UNDER THE SECURITIES ACT, (D) TO AN INSTITUTIONAL
ACCREDITED INVESTOR THAT, PRIOR TO SUCH TRANSFER, FURNISHES TO THE FIRST
NATIONAL BANK OF CHICAGO, AS TRUSTEE (OR, IF THIS CERTIFICATE EVIDENCES COMMON
STOCK, THE TRANSFER AGENT FOR THE COMMON STOCK), A SIGNED LETTER CONTAINING
CERTAIN REPRESEN TATIONS AND AGREEMENTS RELATING TO THE RESTRICTIONS ON TRANSFER
OF THIS SECURITY EVIDENCED HEREBY (THE FORM OF WHICH LETTER CAN BE OBTAINED FROM
SUCH TRUSTEE OR TRANSFER AGENT), (E) OUTSIDE THE UNITED STATES IN COMPLIANCE
WITH RULE 904 UNDER THE SECURITIES ACT OR (F) PURSUANT TO THE EXEMPTION FROM
REGISTRATION PROVIDED BY RULE 144 UNDER THE SECURITIES ACT (IF AVAILABLE), AND
(3) AGREES THAT IT WILL DELIVER TO EACH PERSON TO WHOM THE SECURITY EVIDENCED
HEREBY IS TRANSFERRED A NOTICE SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND.  IN
CONNECTION WITH ANY TRANSFER OF THE SECURITY EVIDENCED HEREBY PRIOR TO THE
EXPIRATION OF THE HOLDING PERIOD APPLICABLE TO SALES OF THE SECURITY EVIDENCED
HEREBY UNDER RULE 144(K) UNDER THE SECURITIES ACT (OR ANY SUCCESSOR PROVISION),
THE HOLDER MUST CHECK THE APPROPRIATE BOX SET FORTH ON THE REVERSE HEREOF
RELATING TO THE MANNER OF SUCH TRANSFER AND SUBMIT THIS CERTIFICATE TO THE FIRST
NATIONAL BANK OF CHICAGO, AS TRUSTEE (OR, IF THIS CERTIFICATE EVIDENCES COMMON
STOCK, SUCH HOLDER MUST FURNISH TO THE TRANSFER AGENT SUCH CERTIFICATIONS, LEGAL

                                      iii
<PAGE>
 
OPINIONS OR OTHER INFORMATION AS THE COMPANY OR McKESSON FINANCING TRUST (THE
"TRUST") MAY REASONABLY REQUIRE TO CONFIRM THAT SUCH TRANSFER IS BEING MADE
PURSUANT TO AN EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE
REGISTRATION REQUIREMENTS OF THE SECURITIES ACT). IF THIS CERTIFICATE DOES NOT
EVIDENCE COMMON STOCK AND IF THE PROPOSED TRANSFEREE IS AN INSTITUTIONAL
ACCREDITED INVESTOR OR A PURCHASER WHO IS NOT A U.S. PERSON, THE HOLDER MUST,
PRIOR TO SUCH TRANSFER, FURNISH TO THE FIRST NATIONAL BANK OF CHICAGO, AS
TRUSTEE, SUCH CERTIFICATIONS, LEGAL OPINIONS OR OTHER INFORMATION AS THE COMPANY
OR THE TRUST MAY REASONABLY REQUIRE TO CONFIRM THAT SUCH TRANSFER IS BEING MADE
PURSUANT TO AN EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE
REGISTRATION REQUIREMENTS OF THE SECURITIES ACT. THIS LEGEND WILL BE REMOVED
AFTER THE EXPIRATION OF THE HOLDING PERIOD APPLICABLE TO SALES OF THE SECURITY
EVIDENCED HEREBY UNDER RULE 144(K) UNDER THE SECURITIES ACT. AS USED HEREIN, THE
TERMS "OFFSHORE TRANSACTION," "UNITED STATES" AND "U.S. PERSON" HAVE THE
MEANINGS GIVEN TO THEM BY REGULATION S UNDER THE SECURITIES ACT.]

                                      iv
<PAGE>
 
                   PREFERRED SECURITIES GUARANTEE AGREEMENT

     This GUARANTEE AGREEMENT (the "Preferred Securities Guarantee"), dated as
of February 20, 1997, is executed and delivered by McKesson Corporation, a
Delaware corporation (the "Guarantor"), and The First National Bank of Chicago,
as trustee (the "Preferred Guarantee Trustee"), for the benefit of the Holders
(as defined herein) from time to time of the Preferred Securities (as defined
herein) of McKesson Financing Trust, a Delaware statutory business trust (the
"Issuer").

     WHEREAS, pursuant to an Amended and Restated Declaration of Trust (the
"Declaration"), dated as of February 20, 1997, among the trustees of the Issuer
named therein, the Guarantor, as sponsor, and the holders from time to time of
undivided beneficial interests in the assets of the Issuer, the Issuer is
issuing on the date hereof up to 4,000,000 preferred securities (the "Preferred
Securities"), having a liquidation amount of $50 per Preferred Security
designated the 5% Trust Convertible Preferred Securities.

     WHEREAS, as incentive for the Holders to purchase the Preferred Securities,
the Guarantor desires irrevocably and unconditionally to agree, to the extent
set forth in this Preferred Securities Guarantee, to pay to the Holders of the
Preferred Securities the Guarantee Payments (as defined herein) and to make
certain other payments on the terms and conditions set forth herein.

     WHEREAS, as of the date hereof, the Guarantor is also executing and
delivering a guarantee agreement (the "Common Securities Guarantee") in
substantially identical terms to this Preferred Securities Guarantee for the
benefit of the holders of the Common Securities (as defined herein), except that
if an Event of Default (as defined in the Indenture), has occurred and is
continuing, the rights of holders of the Common Securities to receive Guarantee
Payments under the Common Securities Guarantee are subordinated to the rights of
Holders of Preferred Securities to receive Guarantee Payments under this
Preferred Securities Guarantee.

     NOW, THEREFORE, in consideration of the purchase by each Holder of
Preferred Securities, which purchase the Guarantor hereby agrees shall benefit
the Guarantor, the Guarantor executes and delivers this Preferred Securities
Guarantee for the benefit of the Holders.


                                   ARTICLE I

                        DEFINITIONS AND INTERPRETATION

     SECTION 1.1  Definitions and Interpretation.

     In this Preferred Securities Guarantee, unless the context otherwise
requires:

     (a) Capitalized terms used in this Preferred Securities Guarantee but not
defined in the preamble above have the respective meanings assigned to them in
this Section 1.1;
<PAGE>
 
     (b) terms defined in the Declaration as at the date of execution of this
Preferred Securities Guarantee have the same meaning when used in this Preferred
Securities Guarantee unless otherwise defined in this Preferred Securities
Guarantee;

     (c) a term defined anywhere in this Preferred Securities Guarantee has the
same meaning throughout;

     (d) all references to "the Preferred Securities Guarantee" or "this
Preferred Securities Guarantee" are to this Preferred Securities Guarantee as
modified, supplemented or amended from time to time;

     (e) all references in this Preferred Securities Guarantee to Articles and
Sections are to Articles and Sections of this Preferred Securities Guarantee,
unless otherwise specified;  term defined in the Trust Indenture Act has the
same meaning when used in this Preferred Securities Guarantee, unless otherwise
defined in this Preferred Securities Guarantee or unless the context otherwise
requires; and

     (f) a reference to the singular includes the plural and vice versa.

     "Authorized Officer" of a Person means any Person that is authorized to
legally bind such Person provided, however, that the Authorized Officer signing
an Officers' Certificate given pursuant to Section 314(a)(4) of the Trust
Indenture Act shall be the principal executive, financial or accounting officer
of such Person.

     "Common Securities" means the securities representing common undivided
beneficial interests in the assets of the Issuer.

     "Corporate Trust Office" means the office of the Preferred Guarantee
Trustee at which the corporate trust business of the Preferred Guarantee Trustee
shall, at any particular time, be principally administered, which office at the
date of execution of this Agreement is located at One First National Plaza,
Suite 0126, Chicago, Illinois 60670-0126, Attention: Corporate Trust Services
Division.

     "Covered Person" means any Holder or beneficial owner of Preferred
Securities.

     "Event of Default" means (a) a failure by the Guarantor to perform any of
its payment or other obligations under this Preferred Securities Guarantee or
(b) if applicable, the failure by the Guarantor to deliver Common Stock upon an
appropriate election by a Holder of Preferred Securities to convert the
Preferred Securities into shares of Common Stock.

     "Guarantee Payments" means the following payments or distributions, without
duplication, with respect to the Preferred Securities, to the extent not paid or
made by the Issuer: (i) any accrued and unpaid Distributions (as defined in the
Declaration) that are required to be paid on such Preferred Securities to the
extent the Issuer shall have funds available therefor, (ii) the redemption price
(the "Redemption Price"), and all accrued and unpaid Distributions to the date
of redemption, to the extent the Issuer has funds available therefor, with
respect to any 

                                       2
<PAGE>
 
Preferred Securities called for redemption by the Issuer, and (iii) upon a
voluntary or involuntary dissolution, winding-up or termination of the Issuer
(other than in connection with the redemption of all of the Preferred Securities
or the distribution of Debentures to the Holders in exchange for Preferred
Securities as provided in the Declaration), the lesser of (a) the aggregate of
the liquidation amount and all accrued and unpaid Distributions on the Preferred
Securities to the date of payment, to the extent the Issuer shall have funds
available therefor, and (b) the amount of assets of the Issuer remaining
available for distribution to Holders of Preferred Securities then outstanding
upon the liquidation of the Issuer (in either case, the "Liquidation
Distribution"). If an Event of Default (as defined in the Indenture) has
occurred and is continuing, the rights of holders of the Common Securities to
receive payments under the Common Securities Guarantee Agreement are
subordinated to the rights of Holders of Preferred Securities to receive
Guarantee Payments.

     "Holder" shall mean any holder, as registered on the books and records of
the Issuer, of any Preferred Securities; provided, however, that, in determining
whether the holders of the requisite percentage of Preferred Securities have
given any request, notice, consent or waiver hereunder, "Holder" shall not
include the Guarantor or any Affiliate of the Guarantor.

     "Indemnified Person" means the Preferred Guarantee Trustee, any Affiliate
of the Preferred Guarantee Trustee, or any officers, directors, shareholders,
members, partners, employees, representatives, nominees, custodians or agents of
the Preferred Guarantee Trustee.

     "Indenture" means the Indenture dated as of February 20, 1997, between the
Guarantor (the "Debenture Issuer") and The First National Bank of Chicago, as
trustee.

     "Majority in liquidation amount of the Preferred Securities" means, except
as provided in the terms of the Convertible Preferred Securities, or except as
provided by the Trust Indenture Act, a vote by Holder(s), voting separately as a
class, of more than 50% of the liquidation amount (including the stated amount
that would be paid on redemption, liquidation or otherwise, plus accrued and
unpaid Distributions to the date upon which the voting percentages are
determined) of all Preferred Securities.

     "Preferred Guarantee Trustee" means The First National Bank of Chicago,
until a Successor Preferred Guarantee Trustee has been appointed and has
accepted such appointment pursuant to the terms of this Preferred Securities
Guarantee and thereafter means each such Successor Preferred Guarantee Trustee.

     "Responsible Officer" means, with respect to the Preferred Guarantee
Trustee, any officer within the Corporate Trust Office of the Preferred
Guarantee Trustee, including any vice president, any assistant vice president,
any assistant secretary, the treasurer, any assistant treasurer or other officer
of the Corporate Trust Office of the Preferred Guarantee Trustee customarily
performing functions similar to those performed by any of the above designated
officers, and also means, with respect to a particular corporate trust matter,
any other officer to whom such matter is referred because of that officer's
knowledge of and familiarity with the particular subject.

                                       3
<PAGE>
 
     "Successor Preferred Guarantee Trustee" means a successor Preferred
Guarantee Trustee possessing the qualifications to act as Preferred Guarantee
Trustee under Section 4.1.

     "Trust Securities" means the Common Securities and the Preferred
Securities.


                                  ARTICLE II

                              TRUST INDENTURE ACT

     SECTION 2.1  Trust Indenture Act; Application.

     (a) Upon its public offering pursuant to the registration requirements of
the Securities Act, this Preferred Securities Guarantee will be subject to the
provisions of the Trust Indenture Act that will be required to be part of this
Preferred Securities Guarantee and shall, to the extent applicable, be governed
by such provisions; and

     (b) if and to the extent that any provision of this Preferred Securities
Guarantee limits, qualifies or conflicts with the duties imposed by Sections 310
to 317, inclusive, of the Trust Indenture Act, such imposed duties shall
control.

     SECTION 2.2  Lists of Holders.

     (a) The Guarantor shall provide the Preferred Guarantee Trustee with a
list, in such form as the Preferred Guarantee Trustee may reasonably require, of
the names and addresses of the Holders ("List of Holders") (i) within 14 days
after each record date for payment of Distributions, as of such record date, and
(ii) at any other time, within 30 days of receipt by the Guarantor of a written
request for a List of Holders as of a date no more than 14 days before such List
of Holders is given to the Preferred Guarantee Trustee, provided that the
Guarantor shall not be obligated to provide such List of Holders at any time the
List of Holders does not differ from the most recent List of Holders given to
the Preferred Guarantee Trustee by the Guarantor.  The Preferred Guarantee
Trustee may destroy any List of Holders previously given to it on receipt of a
new List of Holders.

     (b) The Preferred Guarantee Trustee shall comply with its obligations under
Sections 311(a), 311(b) and Section 312(b) of the Trust Indenture Act.

     SECTION 2.3  Reports by the Preferred Guarantee Trustee.

     Within 60 days after May 15 of each year, the Preferred Guarantee Trustee
shall provide to the Holders such reports as are required by Section 313 of the
Trust Indenture Act, if any, in the form and in the manner provided by Section
313 of the Trust Indenture Act.  The Preferred Guarantee Trustee shall also
comply with the requirements of Section 313(d) of the Trust Indenture Act.

                                       4
<PAGE>
 
     SECTION 2.4  Periodic Reports to Preferred Guarantee Trustee.

     The Guarantor shall provide to the Preferred Guarantee Trustee such
documents, reports and information (if any) as are required by Section 314 and
the compliance certificate required by Section 314 of the Trust Indenture Act in
the form, the manner and at the times required by Section 314 of the Trust
Indenture Act.

     Delivery of such reports, information and documents to the Preferred
Guarantee Trustee is for informational purposes only and the Preferred Guarantee
Trustee's receipt of such shall not constitute constructive notice of any
information contained therein, including the Guarantor's compliance with any of
its covenants hereunder (as to which the Preferred Guarantee Trustee is entitled
to rely exclusively on Officers' Certificates).

     SECTION 2.5  Evidence of Compliance with Conditions Precedent.

     The Guarantor shall provide to the Preferred Guarantee Trustee such
evidence of compliance with any conditions precedent, if any, provided for in
this Preferred Securities Guarantee that relate to any of the matters set forth
in Section 314(c) of the Trust Indenture Act.  Any certificate or opinion
required to be given by an officer pursuant to Section 314(c)(1) may be given in
the form of an Officers' Certificate.

     SECTION 2.6  Events of Default; Waiver.

     The Holders of a Majority in liquidation amount of Preferred Securities
may, by vote, on behalf of the Holders of all of the Preferred Securities, waive
any past Event of Default and its consequences.  Upon such waiver, any such
Event of Default shall cease to exist, and any Event of Default arising
therefrom shall be deemed to have been cured, for every purpose of this
Preferred Securities Guarantee, but no such waiver shall extend to any
subsequent or other default or Event of Default or impair any right consequent
thereon.

     SECTION 2.7  Event of Default; Notice.

     (a) The Preferred Guarantee Trustee shall, within 90 days after the
occurrence of an Event of Default actually known to a Responsible Officer of the
Preferred Guarantee Trustee, transmit by mail, first class postage prepaid, to
the Holders, notices of all such Events of Default unless such defaults have
been cured before the giving of such notice, provided that the Preferred
Guarantee Trustee shall be protected in withholding such notice if and so long
as a Responsible Officer of the Preferred Guarantee Trustee in good faith
determines that the withholding of such notice is in the interests of the
Holders.

     (b) The Preferred Guarantee Trustee shall not be deemed to have knowledge
of any Event of Default unless the Preferred Guarantee Trustee shall have
received written notice thereof, or a Responsible Officer of the Preferred
Guarantee Trustee charged with the administration of this Preferred Securities
Guarantee shall have obtained actual knowledge thereof.

                                       5
<PAGE>
 
     SECTION 2.8  Conflicting Interests.

     The Declaration shall be deemed to be specifically described in this
Preferred Securities Guarantee for the purposes of clause (i) of the first
proviso contained in Section 310(b) of the Trust Indenture Act.


                                  ARTICLE III

           POWERS, DUTIES AND RIGHTS OF PREFERRED GUARANTEE TRUSTEE

     SECTION 3.1  Powers and Duties of the Preferred Guarantee Trustee.

     (a) This Preferred Securities Guarantee shall be held by the Preferred
Guarantee Trustee for the benefit of the Holders and the Preferred Guarantee
Trustee shall not transfer this Preferred Securities Guarantee to any Person
except a Holder exercising his or her rights pursuant to Section 5.4(b) or to a
Successor Preferred Guarantee Trustee on acceptance by such Successor Preferred
Guarantee Trustee of its appointment to act as Successor Preferred Guarantee
Trustee.  The right, title and interest of the Preferred Guarantee Trustee shall
automatically vest in any Successor Preferred Guarantee Trustee, and such
vesting and succession of title shall be effective whether or not conveyancing
documents have been executed and delivered pursuant to the appointment of such
Successor Preferred Guarantee Trustee.

     (b) If an Event of Default actually known to a Responsible Officer of the
Preferred Guarantee Trustee has occurred and is continuing, the Preferred
Guarantee Trustee shall enforce this Preferred Securities Guarantee for the
benefit of the Holders.

     (c) The Preferred Guarantee Trustee, before the occurrence of any Event of
Default and after the curing of all Events of Default that may have occurred,
shall undertake to perform only such duties as are specifically set forth in
this Preferred Securities Guarantee, and no implied covenants shall be read into
this Preferred Securities Guarantee against the Preferred Guarantee Trustee.  In
case an Event of Default has occurred (that has not been cured or waived
pursuant to Section 2.6) and is actually known to a Responsible Officer of the
Preferred Guarantee Trustee, the Preferred Guarantee Trustee shall exercise such
of the rights and powers vested in it by this Preferred Securities Guarantee,
and shall use the same degree of care and skill in its exercise thereof as a
prudent person would exercise or use under the circumstances in the conduct of
his or her own affairs.

     (d) No provision of this Preferred Securities Guarantee shall be construed
to relieve the Preferred Guarantee Trustee from liability for its own negligent
action, its own negligent failure to act, or its own willful misconduct, except
that:

         (i) prior to the occurrence of any Event of Default and after the
     curing or waiving of all such Events of Default that may have occurred:

                                       6
<PAGE>
 
               (A) the duties and obligations of the Preferred Guarantee Trustee
          shall be determined solely by the express provisions of this Preferred
          Securities Guarantee, and the Preferred Guarantee Trustee shall not be
          liable except for the performance of such duties and obligations as
          are specifically set forth in this Preferred Securities Guarantee, and
          no implied covenants or obligations shall be read into this Preferred
          Securities Guarantee against the Preferred Guarantee Trustee; and

               (B) in the absence of bad faith on the part of the Preferred
          Guarantee Trustee, the Preferred Guarantee Trustee may conclusively
          rely, as to the truth of the statements and the correctness of the
          opinions expressed therein, upon any certificates or opinions
          furnished to the Preferred Guarantee Trustee and con forming to the
          requirements of this Preferred Securities Guarantee; but in the case
          of any such certificates or opinions that by any provision hereof are
          specifically required to be furnished to the Preferred Guarantee
          Trustee, the Preferred Guarantee Trustee shall be under a duty to
          examine the same to determine whether or not they conform to the
          requirements of this Preferred Securities Guarantee;

          (ii)   the Preferred Guarantee Trustee shall not be liable for any
     error of judgment made in good faith by a Responsible Officer of the
     Preferred Guarantee Trustee, unless it shall be proved that the Preferred
     Guarantee Trustee was negligent in ascertaining the pertinent facts upon
     which such judgment was made;

          (iii)  the Preferred Guarantee Trustee shall not be liable with
     respect to any action taken or omitted to be taken by it in good faith in
     accordance with the direction of the Holders of not less than a Majority in
     liquidation amount of the Preferred Securities relating to the time, method
     and place of conducting any proceeding for any remedy available to the
     Preferred Guarantee Trustee, or exercising any trust or power conferred
     upon the Preferred Guarantee Trustee under this Preferred Securities
     Guarantee; and

          (iv)   no provision of this Preferred Securities Guarantee shall
     require the Preferred Guarantee Trustee to expend or risk its own funds or
     otherwise incur personal financial liability in the performance of any of
     its duties or in the exercise of any of its rights or powers, if the
     Preferred Guarantee Trustee shall have reasonable grounds for believing
     that the repayment of such funds or liability is not reasonably assured to
     it under the terms of this Preferred Securities Guarantee or indemnity,
     reasonably satisfactory to the Preferred Guarantee Trustee, against such
     risk or liability is not reasonably assured to it.

                                       7
<PAGE>
 
     SECTION 3.2  Certain Rights of Preferred Guarantee Trustee.

     (a)  Subject to the provisions of Section 3.1:

          (i)    The Preferred Guarantee Trustee may conclusively rely, and
     shall be fully protected in acting or refraining from acting upon, any
     resolution, certificate, statement, instrument, opinion, report, notice,
     request, direction, consent, order, bond, debenture, note, other evidence
     of indebtedness or other paper or document believed by it to be genuine and
     to have been signed, sent or presented by the proper party or parties.

          (ii)   Any direction or act of the Guarantor contemplated by this
     Preferred Securities Guarantee shall be sufficiently evidenced by an
     Officers' Certificate.

          (iii)  Whenever, in the administration of this Preferred Securities
     Guarantee, the Preferred Guarantee Trustee shall deem it desirable that a
     matter be proved or established before taking, suffering or omitting any
     action hereunder, the Preferred Guarantee Trustee (unless other evidence is
     herein specifically prescribed) may, in the absence of bad faith on its
     part, request and conclusively rely upon an Officers' Certificate which,
     upon receipt of such request, shall be promptly delivered by the Guarantor.

          (iv)   The Preferred Guarantee Trustee shall have no duty to see to
     any recording, filing or registration of any instrument (or any
     rerecording, refiling or re-registration thereof).

          (v)    The Preferred Guarantee Trustee may consult with counsel of its
     selection, and the advice or opinion of such counsel with respect to legal
     matters shall be full and complete authorization and protection in respect
     of any action taken, suffered or omitted by it hereunder in good faith and
     in accordance with such advice or opinion.  Such counsel may be counsel to
     the Guarantor or any of its Affiliates and may include any of its
     employees.  The Preferred Guarantee Trustee shall have the right at any
     time to seek instructions concerning the administration of this Preferred
     Securities Guarantee from any court of competent jurisdiction.

          (vi)   The Preferred Guarantee Trustee shall be under no obligation to
     exercise any of the rights or powers vested in it by this Preferred
     Securities Guarantee at the request or direction of any Holder, unless such
     Holder shall have provided to the Preferred Guarantee Trustee such security
     and indemnity, reasonably satisfactory to the Preferred Guarantee Trustee,
     against the costs, expenses (including attorneys' fees and expenses and the
     expenses of the Preferred Guarantee Trustee's agents, nominees or
     custodians) and liabilities that might be incurred by it in complying with
     such request or direction, including such reasonable advances as may be
     requested by the Preferred Guarantee Trustee; provided that nothing
     contained in this Section 3.2(a)(vi) shall be taken to relieve the
     Preferred Guarantee Trustee, upon the occurrence of an Event of Default, of
     its obligation to exercise the rights and powers vested in it by this
     Preferred Securities Guarantee.

                                       8
<PAGE>
 
          (vii)  The Preferred Guarantee Trustee shall not be bound to make any
     investigation into the facts or matters stated in any resolution,
     certificate, statement, instrument, opinion, report, notice, request,
     direction, consent, order, bond, debenture, note, other evidence of
     indebtedness or other paper or document, but the Preferred Guarantee
     Trustee, in its discretion, may make such further inquiry or investigation
     into such facts or matters as it may see fit.

          (viii) The Preferred Guarantee Trustee may execute any of the trusts
     or powers hereunder or perform any duties hereunder either directly or by
     or through agents, nominees, custodians or attorneys, and the Preferred
     Guarantee Trustee shall not be responsible for any misconduct or negligence
     on the part of any agent or attorney appointed with due care by it
     hereunder.

          (ix)   Any action taken by the Preferred Guarantee Trustee or its
     agents hereunder shall bind the Holders and the signature of the Preferred
     Guarantee Trustee or its agents alone shall be sufficient and effective to
     perform any such action. No third party shall be required to inquire as to
     the authority of the Preferred Guarantee Trustee to so act or as to its
     compliance with any of the terms and provisions of this Preferred
     Securities Guarantee, both of which shall be conclusively evidenced by the
     Preferred Guarantee Trustee's or its agent's taking such action.

          (x)    Whenever in the administration of this Preferred Securities
     Guarantee the Preferred Guarantee Trustee shall deem it desirable to
     receive instructions with respect to enforcing any remedy or right or
     taking any other action hereunder, the Preferred Guarantee Trustee (i) may
     request instructions from the Holders of a Majority in liquidation amount
     of the Preferred Securities, (ii) may refrain from enforcing such remedy or
     right or taking such other action until such instructions are received, and
     (iii) shall be protected in conclusively relying on or acting in accordance
     with such instructions.

          (xi)   The Preferred Securities Trustee shall not be liable for any
     action taken, suffered, or omitted to be taken by it in good faith and
     reasonably believed by it to be authorized or within the discretion or
     rights or powers conferred upon it by this Preferred Securities Guarantee.

     (b)  No provision of this Preferred Securities Guarantee shall be deemed to
impose any duty or obligation on the Preferred Guarantee Trustee to perform any
act or acts or exercise any right, power, duty or obligation conferred or
imposed on it in any jurisdiction in which it shall be illegal, or in which the
Preferred Guarantee Trustee shall be unqualified or incompetent in accordance
with applicable law, to perform any such act or acts or to exercise any such
right, power, duty or obligation.  No permissive power or authority available to
the Preferred Guarantee Trustee shall be construed to be a duty.

                                       9
<PAGE>
 
     SECTION 3.3  Not Responsible for Recitals or Issuance of Preferred
Securities Guarantee.

     The recitals contained in this Preferred Securities Guarantee shall be
taken as the statements of the Guarantor, and the Preferred Guarantee Trustee
does not assume any responsibility for their correctness.  The Preferred
Guarantee Trustee makes no representation as to the validity or sufficiency of
this Preferred Securities Guarantee.


                                  ARTICLE IV

                          PREFERRED GUARANTEE TRUSTEE

     SECTION 4.1  Preferred Guarantee Trustee: Eligibility.

     (a)  There shall at all times be a Preferred Guarantee Trustee which shall:

          (i)  not be an Affiliate of the Guarantor; and

          (ii) be a corporation organized and doing business under the laws of
     the United States of America or any State or Territory thereof or of the
     District of Columbia, or a corporation or Person permitted by the
     Securities and Exchange Commission to act as an institutional trustee under
     the Trust Indenture Act, authorized under such laws to exercise corporate
     trust powers, having a combined capital and surplus of at least 50 million
     U.S. dollars ($50,000,000), and subject to supervision or examination by
     federal, state, territorial or District of Columbia authority.  If such
     corporation publishes reports of condition at least annually, pursuant to
     law or to the requirements of the supervising or examining authority
     referred to above, then, for the purposes of this Section 4.1(a)(ii), the
     combined capital and surplus of such corporation shall be deemed to be its
     combined capital and surplus as set forth in its most recent report of
     condition so published.

     (b)  If at any time the Preferred Guarantee Trustee shall cease to be
eligible to so act under Section 4.1(a), the Preferred Guarantee Trustee shall
immediately resign in the manner and with the effect set out in Section 4.2(c).

     (c)  If the Preferred Guarantee Trustee has or shall acquire any
"conflicting interest" within the meaning of Section 310(b) of the Trust
Indenture Act, the Preferred Guarantee Trustee and Guarantor shall in all
respects comply with the provisions of Section 310(b) of the Trust Indenture
Act.

     SECTION 4.2  Appointment, Removal and Resignation of Preferred Guarantee
Trustee.

     (a)  Subject to Section 4.2(b), the Preferred Guarantee Trustee may be
appointed or removed without cause at any time by the Guarantor.

                                       10
<PAGE>
 
     (b)  The Preferred Guarantee Trustee shall not be removed in accordance
with Section 4.2(a) until a Successor Preferred Guarantee Trustee has been
appointed and has accepted such appointment by written instrument executed by
such Successor Preferred Guarantee Trustee and delivered to the Guarantor.

     (c)  The Preferred Guarantee Trustee appointed to office shall hold office
until a Successor Preferred Guarantee Trustee shall have been appointed or until
its removal or resignation.  The Preferred Guarantee Trustee may resign from
office (without need for prior or subsequent accounting) by an instrument in
writing executed by the Preferred Guarantee Trustee and delivered to the
Guarantor, which resignation shall not take effect until a Successor Preferred
Guarantee Trustee has been appointed and has accepted such appointment by
instrument in writing executed by such Successor Preferred Guarantee Trustee and
delivered to the Guarantor and the resigning Preferred Guarantee Trustee.

     (d)  If no Successor Preferred Guarantee Trustee shall have been appointed
and accepted appointment as provided in this Section 4.2 within 60 days after
delivery of an instrument of resignation or removal, the Preferred Guarantee
Trustee resigning or being removed may petition any court of competent
jurisdiction for appointment of a Successor Preferred Guarantee Trustee.  Such
court may thereupon, after prescribing such notice, if any, as it may deem
proper, appoint a Successor Preferred Guarantee Trustee.

     (e)  No Preferred Guarantee Trustee shall be liable for the acts or
omissions to act of any Successor Preferred Guarantee Trustee.

     (f)  Upon termination of this Preferred Securities Guarantee or removal or
resignation of the Preferred Guarantee Trustee pursuant to this Section 4.2, the
Guarantor shall pay to the Preferred Guarantee Trustee all amounts accrued to
the date of such termination, removal or resignation.


                                   ARTICLE V

                                   GUARANTEE

     SECTION 5.1  Guarantee.

     The Guarantor irrevocably and unconditionally agrees to pay in full to the
Holders the Guarantee Payments (without duplication of amounts theretofore paid
by the Issuer), as and when due, regardless of any defense, right of set-off or
counterclaim that the Issuer may have or assert.  The Guarantor's obligation to
make a Guarantee Payment may be satisfied by direct payment of the required
amounts by the Guarantor to the Holders or by causing the Issuer to pay such
amounts to the Holders.  The Guarantor will honor all obligations relating to
the conversion of the Preferred Securities into the Common Stock of the
Guarantor as set forth in the Declaration and the Indenture.

                                       11
<PAGE>
 
     SECTION 5.2  Waiver of Notice and Demand.

     The Guarantor hereby waives notice of acceptance of this Preferred
Securities Guarantee and of any liability to which it applies or may apply,
presentment, demand for payment, any right or remedy to require a proceeding
first against the Issuer or any other Person before proceeding directly against
the Guarantor, protest, notice of nonpayment, notice of dishonor, notice of
redemption and all other notices and demands.

     SECTION 5.3  Obligations Not Affected.

     The obligations, covenants, agreements and duties of the Guarantor under
this Preferred Securities Guarantee shall in no way be affected or impaired by
reason of the happening from time to time of any of the following:

     (a)  the release or waiver, by operation of law or otherwise, of the
performance or observance by the Issuer of any express or implied agreement,
covenant, term or condition relating to the Preferred Securities to be performed
or observed by the Issuer;

     (b)  the extension of time for the payment by the Issuer of all or any
portion of the Distributions, Redemption Price, Liquidation Distribution or any
other sums payable under the terms of the Preferred Securities or the extension
of time for the performance of any other obligation under, arising out of, or in
connection with, the Preferred Securities (other than an extension of time for
payment of Distributions, Redemption Price, Liquidation Distribution or other
sum payable that results from the extension of any interest payment period on
the Debentures);

     (c)  any failure, omission, delay or lack of diligence on the part of the
Holders to enforce, assert or exercise any right, privilege, power or remedy
conferred on the Holders pursuant to the terms of the Preferred Securities, or
any action on the part of the Issuer granting indulgence or extension of any
kind;

     (d)  the voluntary or involuntary liquidation, dissolution, sale of any
collateral, receiver ship, insolvency, bankruptcy, assignment for the benefit of
creditors, reorganization, arrangement, composition or readjustment of debt of,
or other similar proceedings affecting, the Issuer or any of the assets of the
Issuer;

     (e)  any invalidity of, or defect or deficiency in, the Preferred
Securities;

     (f)  the settlement or compromise of any obligation guaranteed hereby or
hereby incurred; or

     (g)  any other circumstance whatsoever that might otherwise constitute a
legal or equitable discharge or defense of a guarantor, it being the intent of
this Section 5.3 that the obligations of the Guarantor hereunder shall be
absolute and unconditional under any and all circumstances.

                                       12
<PAGE>
 
     There shall be no obligation of the Holders to give notice to, or obtain
consent of, the Guarantor with respect to the happening of any of the foregoing.

     SECTION 5.4  Rights of Holders.

     (a)  The Holders of a Majority in liquidation amount of the Preferred
Securities then outstanding have the right to direct the time, method and place
of conducting any proceeding for any remedy available to the Preferred Guarantee
Trustee in respect of this Preferred Securities Guarantee or to direct the
exercise of any trust or power conferred upon the Preferred Guarantee Trustee
under this Preferred Securities Guarantee.

     (b)  If the Preferred Guarantee Trustee fails to enforce this Preferred
Securities Guarantee, any Holder of Preferred Securities may institute a legal
proceeding directly against the Guarantor to enforce the Preferred Guarantee
Trustee's rights under this Preferred Securities Guarantee, without first
instituting a legal proceeding against the Issuer, the Preferred Guarantee
Trustee or any other person or entity.  The Guarantor waives any right or remedy
to require that any action be brought first against the Issuer or any other
person or entity before proceeding directly against the Guarantor.
Notwithstanding the foregoing, if the Guarantor has failed to make a guarantee
payment, a Holder of Preferred Securities may directly institute a proceeding
against the Guarantor for enforcement of this Preferred Securities Guarantee for
such payment.

     SECTION 5.5  Guarantee of Payment.

     This Preferred Securities Guarantee creates a guarantee of payment and not
of collection.

     SECTION 5.6  Subrogation.

     The Guarantor shall be subrogated to all (if any) rights of the Holders of
Preferred Securities against the Issuer in respect of any amounts paid to such
Holders by the Guarantor under this Preferred Securities Guarantee; provided,
however, that the Guarantor shall not (except to the extent required by
mandatory provisions of law) be entitled to enforce or exercise any right that
it may acquire by way of subrogation or any indemnity, reimbursement or other
agreement, in all cases as a result of payment under this Preferred Securities
Guarantee, if, at the time of any such payment, any amounts are due and unpaid
under this Preferred Securities Guarantee.  If any amount shall be paid to the
Guarantor in violation of the preceding sentence, the Guarantor agrees to hold
such amount in trust for the Holders and to pay over such amount to the Holders.

     SECTION 5.7  Independent Obligations.

     The Guarantor acknowledges that its obligations hereunder are independent
of the obligations of the Issuer with respect to the Preferred Securities, and
that the Guarantor shall be liable as principal and as debtor hereunder to make
Guarantee Payments pursuant to the terms of this Preferred Securities Guarantee
notwithstanding the occurrence of any event referred to in subsections (a)
through (g), inclusive, of Section 5.3 hereof.

                                       13
<PAGE>
 
                                  ARTICLE VI

                   LIMITATION OF TRANSACTIONS; SUBORDINATION

     SECTION 6.1  Limitation of Transactions.

     So long as any Preferred Securities remain outstanding, if (i) the
Guarantor has exercised its option to defer interest payments on the Debentures
by extending the interest payment period and such extension period, or any
extension thereof, shall be continuing, (ii) the Guarantor shall be in default
with respect to its payment or other obligations under this Preferred Securities
Guarantee or (iii) there shall have occurred and be continuing an Event of
Default under the Declaration or any event that, with the giving of notice or
lapse of time or both, would constitute an Event of Default under the
Declaration, then the Guarantor shall not (a) declare or pay any dividend on,
make any distributions with respect to, or redeem, purchase, acquire, or make
any liquidation payment with respect to, any of its capital stock or (b) make
any payment of interest, principal or premium, if any, on or repay, repurchase
or redeem any debt securities of the Guarantor that rank pari passu with or
junior in interest to the Debentures or make any guarantee payment with respect
to any guarantee by the Guarantor of the debt securities of any subsidiary of
the Guarantor if such guarantee ranks pari passu with or junior in interest to
the Debentures (other than (i) as a result of a reclassification of the capital
stock of the Guarantor or the exchange or conversion of one class or series of
the capital stock of the Guarantor for another class or series of the capital
stock of the Guarantor, (ii) the purchase of fractional interests in shares of
the capital stock of the Guarantor pursuant to the conversion or exchange
provisions of such capital stock or the security being converted into or
exchanged for such capital stock, (iii) dividends or distributions in Common
Stock of the Guarantor, (iv) any declaration of a dividend in connection with
the implementation of a stockholders' rights plan, or the issuance of stock
under any such plan in the future, or the redemption or repurchase of any such
rights pursuant thereto, (v) payments under the Guarantee and Common Securities
Guarantee, (vi) purchases of Common Stock of the Guarantor related to the
issuance of Common Stock of the Guarantor or rights under any of the Guarantor's
benefit plans for its directors, officers or employees and (vii) obligations
under any dividend reinvestment and stock purchase plans).

     SECTION 6.2  Subordination.

     This Preferred Securities Guarantee will constitute an unsecured obligation
of the Guarantor and will rank (i) subordinate and junior in right of payment to
all other liabilities of the Guarantor (except any liabilities that may be pari
passu expressly by their terms), (ii) pari passu with the most senior preferred
or preference stock now or hereafter issued by the Guarantor and with any
guaranty now or hereafter entered into by the Guarantor in respect of any
preferred or preference stock of any Affiliate of the Guarantor and (iii) senior
to the Guarantor's common stock.

                                       14
<PAGE>
 
                                  ARTICLE VII

                                  TERMINATION

     SECTION 7.1  Termination.

     This Preferred Securities Guarantee shall terminate as to each Holder upon
(i) full payment of the Redemption Price and accrued and unpaid distributions
with respect to all Preferred Securities, (ii) the distribution of the Common
Stock to such Holder upon the conversion of such Holder's Preferred Securities
into the Common Stock, (iii) the distribution of the Debentures to the Holders
of the Preferred Securities or (iv) full payment of the amounts payable in
accordance with the Declaration upon liquidation of the Issuer. This Preferred
Securities Guarantee shall terminate completely upon full payment of the amounts
payable in accordance with the Declaration. Notwithstanding the foregoing, this
Preferred Securities Guarantee will continue to be effective or will be
reinstated, as the case may be, if at any time any Holder must restore payment
of any sum paid under the Preferred Securities or under this Preferred
Securities Guarantee.


                                 ARTICLE VIII

                                INDEMNIFICATION

     SECTION 8.1  Exculpation.

     (a)  No Indemnified Person shall be liable, responsible or accountable in
damages or otherwise to the Guarantor or any Covered Person for any loss,
damage, liability, expense or claim incurred by reason of any act or omission
performed or omitted by such Indemnified Person in good faith in accordance with
this Preferred Securities Guarantee and in a manner that such Indemnified Person
reasonably believed to be within the scope of the authority conferred on such
Indemnified Person by this Preferred Securities Guarantee or by law, except that
an Indemnified Person shall be liable for any such loss, damage or claim
incurred by reason of such Indemnified Person's negligence or willful misconduct
with respect to such acts or omissions.

     (b)  An Indemnified Person shall be fully protected in relying in good
faith upon the records of the Guarantor and upon such information, opinions,
reports or statements presented to the Guarantor by any Person as to matters the
Indemnified Person reasonably believes are within such other Person's
professional or expert competence and who has been selected with reasonable care
by or on behalf of the Guarantor, including information, opinions, reports or
statements as to the value and amount of the assets, liabilities, profits,
losses or any other facts pertinent to the existence and amount of assets from
which Distributions to Holders might properly be paid.

                                       15
<PAGE>
 
     SECTION 8.2  Indemnification.

     The Guarantor agrees to indemnify each Indemnified Person for, and to hold
each Indemnified Person harmless against, any loss, liability or expense
incurred without negligence or bad faith on its part, arising out of or in
connection with the acceptance or administration of the trust or trusts
hereunder, including the costs and expenses (including reasonable legal fees and
expenses) of defending itself against, or investigating, any claim or liability
in connection with the exercise or performance of any of its powers or duties
hereunder.  The provisions of this Section 8.2 shall survive the termination of
this Preferred Securities Guarantee or the resignation or removal of the
Preferred Guarantee Trustee.

     When the Preferred Guarantee Trustee incurs expenses or renders services in
connection with an Event of Default specified in Section 5.1(d) or Section
5.1(e) of the Indenture, the expenses (including the reasonable charges and
expenses of its counsel) and the compensation for services are intended to
constitute expenses of administration under any applicable federal or state
bankruptcy, insolvency or other similar law.


                                  ARTICLE IX

                                 MISCELLANEOUS

     SECTION 9.1  Successors and Assigns.

     All guarantees and agreements contained in this Preferred Securities
Guarantee shall bind the successors, assigns, receivers, trustees and
representatives of the Guarantor and shall inure to the benefit of the Holders
of the Preferred Securities then outstanding.  Except in connection with any
merger or consolidation of the Guarantor with or into another entity permitted
by Section 9.1 of the Indenture or any sale, transfer or lease of the
Guarantor's assets to another entity permitted by Section 9.1 of the Indenture,
the Guarantor may not assign its rights or delegate its obligations under this
Preferred Securities Guarantee without the prior approval of the holders of at
least a Majority in liquidation amount of the Preferred Securities then
outstanding.

     SECTION 9.2  Amendments.

     Except with respect to any changes that do not adversely affect the rights
of Holders (in which case no consent of Holders will be required), this
Preferred Securities Guarantee may only be amended with the prior approval of
the Holders of at least a Majority in liquidation amount (including the stated
amount that would be paid on redemption, liquidation or otherwise, plus accrued
and unpaid Distributions to the date upon which the voting percentages are
determined) of the Preferred Securities then outstanding. The provisions of
Section 12.2 of the Declaration with respect to meetings of Holders apply to the
giving of such approval.

                                       16
<PAGE>
 
     SECTION 9.3  Notices.

     All notices provided for in this Preferred Securities Guarantee shall be in
writing, duly signed by the party giving such notice, and shall be delivered,
telecopied or mailed by first class mail, as follows:

     (a)  If given to the Preferred Guarantee Trustee, at the Preferred
Guarantee Trustee's mailing address set forth below (or such other address as
the Preferred Guarantee Trustee may give notice of to the Holders of the
Preferred Securities):

               The First National Bank of Chicago
               One First National Plaza, Suite 0126
               Chicago, Illinois  60670-0126

               Attention:  Corporate Trust Services Division

     (b)  If given to the Guarantor, at the Guarantor's mailing address set
forth below (or such other address as the Guarantor may give notice of to the
Holders of the Preferred Securities):

               McKesson Corporation
               McKesson Plaza
               One Post Street
               San Francisco, California  94104

               Attention:  General Counsel

     (c)  If given to any Holder of Preferred Securities, at the address set
forth on the books and records of the Issuer.

     All such notices shall be deemed to have been given when received in
person, telecopied with receipt confirmed, or mailed by first class mail,
postage prepaid, except that if a notice or other document is refused delivery
or cannot be delivered because of a changed address of which no notice was
given, such notice or other document shall be deemed to have been delivered on
the date of such refusal or inability to deliver.

     SECTION 9.4  Benefit.

     This Preferred Securities Guarantee is solely for the benefit of the
Holders of the Preferred Securities and, subject to Section 3.1(a), is not
separately transferable from the Preferred Securities.

                                       17
<PAGE>
 
     SECTION 9.5  Governing Law.

     THIS PREFERRED SECURITIES GUARANTEE SHALL BE GOVERNED BY, AND CONSTRUED AND
INTERPRETED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK, WITHOUT
REGARD TO CONFLICT OF LAWS PRINCIPLES THEREOF.

                                       18
<PAGE>
 
     THIS PREFERRED SECURITIES GUARANTEE is executed as of the day and year
first above written.


                              McKESSON CORPORATION, as Guarantor

 
                              By:  /s/ Ivan D. Meyerson           
                                   --------------------------------           
                                   Name:  Ivan D. Meyerson          
                                   Title:    Vice President         
                                                                  
                                                                  
                              THE FIRST NATIONAL BANK OF CHICAGO, 
                              as Preferred Guarantee Trustee      
                                                                  
                                                                  
                                                                  
                              By:  /s/ Richard D. Manella         
                                   --------------------------------
                                   Name:  Richard D. Manella        
                                   Title:    Vice President          

                                       19

<PAGE>
 
                                                                     EXHIBIT 5.1


           [LETTERHEAD OF SKADDEN, ARPS, SLATE, MEAGHER & FLOM LLP]


                                                May 2, 1997

McKesson Corporation
McKesson Financing Trust
c/o McKesson Corporation
    McKesson Plaza
    One Post Street
    San Francisco, CA  94104

Ladies and Gentlemen:

          We have acted as special counsel to McKesson Corporation, a Delaware
corporation (the "Company"), and McKesson Financing Trust, a business trust
formed under the Business Trust Act of the State of Delaware (Chapter 38, Title
12, of the Delaware Code, 12 Del. L. Sec. 3801 et. seq.) (the "Trust"), in
connection with the preparation of the Registration Statement on Form S-3 (such
Registration Statement being hereinafter referred to as the "Registration
Statement") to be filed by the Company and the Trust with the Securities and
Exchange Commission (the "Commission") on the date hereof with respect to the
registration under the Securities Act of 1933, as amended (the "Act"), (i) by
the Trust of 4,000,000 5% Trust Convertible Preferred Securities (the
"Convertible Preferred Securities"); (ii) by the Company of its guarantee of
payments of cash distributions and payments on liquidation of the Trust or
redemption of the Convertible Preferred Securities pursuant to the Preferred
Securities Guarantee Agreement (the "Guarantee Agreement"), (iii) by the Company
of $200,000,000 aggregate principal amount of its 5% Convertible Subordinated
Debentures due June 1, 2027 (the "Convertible Subordinated Debentures") and (iv)
by the Company of such number of shares of common stock of the Company, par
value $0.01 per share ("Company Common Stock"), as are issuable upon conversion
of the Convertible Subordinated Debentures and such indeterminate number of
shares of Company Common Stock as may be issuable pursuant to certain anti-
dilution adjustments.

          The Convertible Preferred Securities were issued pursuant to the
Amended and Restated Declaration of Trust of the Trust, dated as of February 20,
1997 (the "Declaration"), among William A. Armstrong and Ivan D. Meyerson, as
regular trustees, The First National Bank of Chicago, as
<PAGE>
 
McKesson Corporation
McKesson Financing Trust
May 2, 1997
Page 2



trustee (the "Institutional Trustee"), First Chicago Delaware Inc., as Delaware
trustee and the Company, as sponsor.

          This opinion is being furnished in accordance with the requirements of
Item 601(b)(5) of Regulation S-K under the Act.

          In connection with this opinion, we have examined originals or copies,
certified or otherwise identified to our satisfaction, of (i) the Registration
Statement; (ii) an executed copy of the Registration Rights Agreement, dated as
of February 20, 1997 (the "Registration Rights Agreement"), among the Company,
the Trust and Morgan Stanley & Co. Incorporated; (iii) an executed copy of the
Indenture, dated as of February 20, 1997, between The First National Bank of
Chicago, as trustee, and the Company; (iv) the form of the Convertible Preferred
Securities and a specimen certificate thereof; (v) the form of the Convertible
Subordinated Debentures and a specimen certificate thereof; (vi) the Guarantee
Agreement; (vii) the Restated Certificate of Incorporation and Restated By-Laws
of the Company; (viii) the Certificate of Trust of the Trust filed with the
Secretary of State of the State of Delaware on February 5, 1997; and (ix) the
Declaration. We have also examined originals or copies, certified or otherwise
identified to our satisfaction, of such other documents, certificates and
records as we have deemed necessary or appropriate as a basis for the opinions
set forth herein. The documents referred to in clauses (ii), (iii), (vi), (viii)
and (ix) are hereinafter referred to as the "Operative Documents".

          In our examination, we have assumed the legal capacity of all natural
persons, the genuineness of all signatures, the authenticity of all documents
submitted to us as originals, the conformity to original documents of all
documents submitted to us as certified or photostatic copies and the
authenticity of the originals of such latter documents.  In making our
examination of documents executed by parties other than the Company and the
Trust, we have assumed that such parties had the power, corporate or other, to
enter into and perform all obligations thereunder and have also assumed the due
authorization by all requisite
<PAGE>
 
McKesson Corporation
McKesson Financing Trust
May 2, 1997
Page 3



action, corporate or other, and execution and delivery by such parties of such
documents and, except to the extent set forth in paragraphs 2 and 3 below, the
validity and binding effect thereof on such parties. We have also assumed that
the execution and delivery by the Company of the Guarantee Agreement, the
Indenture and the Convertible Subordinated Debentures and the performance of its
obligations thereunder do not and will not violate, conflict with or constitute
a default under (i) any agreement or instrument to which the Company or its
properties is subject (except that we do not make the assumption set forth in
this clause (i) with respect to the Restated Certificate of Incorporation or the
Restated By-Laws of the Company or the Operative Documents), (ii) any law, rule,
or regulation to which the Company is subject (except that we do not make the
assumption set forth in this clause (ii) with respect to the Delaware Business
Trust Act, the Delaware General Corporation Law (the "DGCL") or those laws,
rules and regulations of the State of New York and the United States of America
which, in our experience, are normally applicable to transactions of the type
contemplated by the Operative Documents, but without our having made any special
investigation concerning any other laws, rules or regulations), (iii) any
judicial or regulatory order or decree of any governmental authority or (iv) any
consent, approval, license, authorization or validation of, or filing, recording
or registration with any governmental authority. As to any facts material to the
opinions expressed herein which we did not independently establish or verify, we
have relied upon oral or written statements and representations of officers,
trustees and other representatives of the Company, the Trust and others.

          Members of our firm are admitted to the Bar of the State of New York,
and we do not express any opinion as to the laws of any jurisdiction other than
the laws of the State of New York, the DGCL and the Business Trust Act of the
State of Delaware.

          Based upon and subject to the foregoing, we are of the opinion that:

          1.    The Convertible Preferred Securities have been duly authorized
for issuance by the Trust, and repre-
<PAGE>
 
McKesson Corporation
McKesson Financing Trust
May 2, 1997
Page 4



sent, subject to the qualifications set forth in paragraph 5 below, fully paid
and nonassessable undivided beneficial interests in the assets of the Trust.

          2.     The Guarantee Agreement has been duly authorized, executed and
delivered by the Company, and is a valid, legal and binding agreement of the
Company in favor of the holders of Convertible Preferred Securities, enforceable
against the Company in accordance with its terms, except (a) to the extent that
enforcement thereof may be limited by (i) bankruptcy, insolvency (including,
without limitation, all laws relating to fraudulent transfers), reorganization,
moratorium or other similar laws now or hereafter in effect relating to
creditors' rights generally, and (ii) general principles of equity (regardless
of whether enforcement is considered in a proceeding in equity or at law), and
(b) we express no opinion regarding the enforceability or effect of Section 8.2
of the Guarantee Agreement.

          3. The Convertible Subordinated Debentures have been duly authorized,
executed, issued and delivered by the Company, and constitute valid, legal and
binding obligations of the Company entitled to the benefits of the Indenture and
enforceable against the Company in accordance with their terms, except (a) to
the extent that enforcement thereof may be limited by (i) bankruptcy, insolvency
(including, without limitation, all laws relating to fraudulent transfers),
reorganization, moratorium or other similar laws now or hereafter in effect
relating to creditors' rights generally, and (ii) general principles of equity
(regardless of whether enforcement is considered in a proceeding in equity or at
law), and (b) we express no opinion regarding the enforceability or effect of
Section 6.7 of the Indenture.

          4.     The shares of Company Common Stock initially issuable upon
conversion of the Convertible Subordinated Debentures have been duly authorized
and reserved for issuance by the Company and, if and when issued, upon
conversion of the Convertible Subordinated Debentures in accordance with the
provisions of the Indenture, at conversion prices at or in excess of the par
value of such shares of Company
<PAGE>
 
McKesson Corporation
McKesson Financing Trust
May 2, 1997
Page 5



Common Stock, such shares of Company Common Stock will be validly issued, fully
paid and nonassessable.

          5.     The holders of the Convertible Preferred Securities will be
entitled to the same limitation of personal liability extended to stockholders
of private corporations for profit organized under the DGCL.  We bring to your
attention, however, that the holders of the Convertible Preferred Securities may
be obligated, pursuant to the Declaration, to (i) provide indemnity and/or
security in connection with, and pay taxes or governmental charges arising from,
transfers of Convertible Preferred Securities and the issuance of replacement
Convertible Preferred Securities and (ii) provide security and indemnity in
connection with requests of or directions to the Institutional Trustee to
exercise its rights and powers under the Declaration.

          We hereby consent to the filing of this opinion with the Commission as
an exhibit to the Registration Statement.  We also consent to the reference to
our firm under the caption "Legal Matters" in the Registration Statement.  In
giving this consent, we do not thereby admit that we are included in the
category of persons whose consent is required under Section 7 of the Act or the
rules and regulations of the Commission.  This opinion is expressed as of the
date hereof, and we disclaim any undertaking to advise you of any subsequent
changes in the facts stated or assumed herein or of any subsequent changes in
applicable law.

                                            Very truly yours,

<PAGE>
 
                                                                     Exhibit 8.1
                                                                     -----------


           [LETTERHEAD OF SKADDEN, ARPS, SLATE, MEAGHER & FLOM LLP]



                                  May 2, 1997


McKesson Corporation
McKesson Financing Trust
McKesson Plaza
One Post Street
San Francisco, California  94104

          Re:  Registration Statement on Form S-3
               ----------------------------------
 

Ladies and Gentlemen:

     We have acted as special tax counsel to McKesson Financing Trust, a
statutory business trust organized under the Business Trust Act of the State of
Delaware (Chapter 38, Title 12 of the Delaware Code, 12 Del. C. Sec. 3801, et
seq.) (the "Trust"), in connection with the preparation of a Registration
Statement on Form S-3 of McKesson Corporation, a Delaware corporation (the
"Company"), and the Trust filed by the Company and the Trust with the Securities
and Exchange Commission (the "Commission") under the Securities Act of 1933, as
amended (the "Securities Act"), on May 2, 1997 the "Registration Statement"),
relating to the registration (i) by the Trust of 4,000,000 shares of the Trust's
5% Trust Convertible Preferred Securities (liquidation amount $50 per
convertible preferred security) (the "Convertible Preferred Securities"),
representing undivided beneficial interests in the assets of the Trust, and (ii)
by the Company of the shares of common stock, par value $.01 per share, of the
Company (the "Company Common Stock") issuable upon conversion of the Preferred
Securities, and certain other securities.

     We hereby confirm that, although the discussion set forth in the above
captioned registration statement under the heading "UNITED STATES FEDER

                                       1
<PAGE>
 
McKesson Corporation
McKesson Financing Trust
May 2, 1997
Page 2


AL INCOME TAXATION" does not purport to discuss all possible United States
federal income tax consequences of the purchase, ownership and disposition of
the Convertible Preferred Securities, in our opinion such discussion
constitutes, in all material respects, a fair and accurate summary of the United
States federal income tax consequences of the purchase, ownership and
disposition of the Convertible Preferred Securities, based upon current law.
There can be no assurances that any of the opinions expressed herein will be
accepted by the Internal Revenue Service, or if challenged, by a court.

     We hereby consent to the filing of this opinion with the Commission as
Exhibit 8.1 to the Registration Statement. We also consent to the use of our
name under the heading "Legal Matters" in the Registration Statement. In giving
this consent, we do not thereby admit that we are within the category of persons
whose consent is required under Section 7 of the Securities Act or the rules and
regulations of the Commission promulgated thereunder. This opinion is expressed
as of the date hereof unless otherwise expressly stated and we disclaim any
undertaking to advise you of any subsequent changes of the facts stated or
assumed herein or any subsequent changes in applicable law.

               Very truly yours,


               SKADDEN, ARPS, SLATE, MEAGHER & FLOM LLP

                                       2

<PAGE>
 
                                                                    Exhibit 10.1
                                                                    ------------


                         REGISTRATION RIGHTS AGREEMENT

          THIS REGISTRATION RIGHTS AGREEMENT (the "Agreement") is made and
                                                   ---------              
entered into as of February 20, 1997 among McKesson Corporation, a Delaware
corporation ("McKesson" or the "Company"), McKesson Financing Trust, a statutory
              --------          -------                                         
business trust formed under the laws of the State of Delaware (the "Trust"), and
                                                                    -----       
Morgan Stanley & Co. Incorporated (the "Initial Purchaser") pursuant to the
                                        -----------------                  
Placement Agreement dated as of February 13, 1997 (the "Placement Agreement")
                                                        -------------------  
among McKesson, the Trust and the Initial Purchaser.  In order to induce the
Initial Purchaser to enter into the Placement Agreement, McKesson and the Trust
have agreed to provide the registration rights set forth in this Agreement.  The
execution of this Agreement is a condition to the closing under the Placement
Agreement.

          McKesson and the Trust agree with the Initial Purchaser, (i) for its
benefit as Initial Purchaser and (ii) for the benefit of the holders from time
to time of the Registrable Securities (including the Initial Purchaser) (each of
the foregoing a "Holder" and together the "Holders"), as follows:
                 ------                    -------               

Section 1.  Definitions.

          Capitalized terms used herein without definition shall have their
respective meanings set forth in the Placement Agreement.  As used in this
Agreement, the following terms shall have the following meanings:

          Affiliate: "Affiliate" has the same meaning as given to that term in
Rule 405 of the Securities Act or any successor rule thereunder.

          Applicable Conversion Price: The Applicable Conversion Price as of any
date of determination means the Conversion Price, as it may be adjusted from
time to time, in effect as of such date of determination or, if no Convertible
Debentures are then outstanding, the Conversion Price that would be in effect
were Convertible Debentures then outstanding.

          Business Day: Any day other than a Saturday, Sunday or any other day
on which banking institutions in The City of New York or Wilmington, Delaware
are permitted or required by law to close.

          Common Stock: The shares of common stock, $.01 par value per share, of
McKesson and any other shares of common stock as may constitute "Common Stock"
for purposes of the Indenture, including the Underlying Common Stock.

          Conversion Price: Conversion Price shall have the meaning assigned
such term in Section 14.1 of the Indenture.
<PAGE>
 
          Convertible Debentures: The 5% Convertible Junior Subordinated
Debentures due 2027 of McKesson to be purchased by the Trust pursuant to the
Debenture Purchase Agreement dated as of the date hereof between McKesson and
the Trust.

          Convertible Preferred Securities: The 5% Trust Convertible Preferred
Securities of the Trust.

          Damages Accrual Period:  See Section 2(e) hereof.

          Damages Payment Date: Each distribution payment date under the
Declaration, in the case of Convertible Preferred Securities, each Interest
Payment Date (as defined in the Indenture), in the case of Convertible
Debentures, and each March 1, June 1, September 1, December 1, in the case of
Underlying Common Stock; and, in the event that any Convertible Preferred
Security or Convertible Debenture (or portion thereof) is called for redemption
or surrendered for conversion, the date of redemption or conversion, as the case
may be, shall be deemed to be a Damages Payment Date with respect to such
Convertible Preferred Security or Convertible Debenture (or portion thereof), as
the case may be, unless accrued and unpaid distributions or interest, as the
case may be, are to be paid to the holder on a record date prior to such date of
conversion (in which case the Damages Payment Date shall be deemed to be the
date on which distributions or interest, as the case may be, are payable to such
record holder).

          Declaration:  The Amended and Restated Declaration of Trust dated as
of the date hereof of the Trust as amended from time to time.

          Deferral Period: See Section 2(d)(ii) hereof.

          Effectiveness Period: The period commencing with the date hereof and
ending on the date that all Registrable Securities have ceased to be Registrable
Securities.

          Event:  See Section 2(e) hereof.

          Event Date: See Section 2(e) hereof.

          Event Termination Date:  See Section 2(e) hereof.

          Exchange Act: The Securities Exchange Act of 1934, as amended, and the
rules and regulations of the SEC promulgated thereunder.

          Filing Date:  See Section 2(a) hereof.

          Guarantee:  The guarantee by McKesson of the Convertible Preferred
Securities pursuant to the Preferred Securities Guarantee Agreement dated as of
the date hereof between McKesson and The First National Bank of Chicago, as
preferred guarantee trustee.

          Holder:  See the second paragraph of this Agreement.

                                       2
<PAGE>
 
          Indenture:  The Indenture date as of February 20, 1997 between
McKesson and The First National Bank of Chicago, as trustee, pursuant to which
the Convertible Debentures are being issued.

          Initial Purchaser:  Morgan Stanley & Co. Incorporated.

          Initial Shelf Registration: See Section 2(a) hereof.

          Liquidated Damages Amount:  See Section 2(e) hereof.

          Notice Holder: See Section 2(d)(i) hereof.

          Placement Agreement:  See the first paragraph of this Agreement.

          Prospectus:  The prospectus included in any Registration Statement
(including, without limitation, a prospectus that discloses information
previously omitted from a prospectus filed as part of an effective registration
statement in reliance upon Rule 430A promulgated under the Securities Act), as
amended or supplemented by any amendment or prospectus supplement, including
post-effective amendments, and all material incorporated by reference or deemed
to be incorporated by reference in such Prospectus.

          Registrable Securities: The Convertible Preferred Securities, the
Guarantee, the Convertible Debentures and the Underlying Common Stock, whether
or not such securities have been converted or exchanged, and at all times
subsequent to any such conversion or exchange, and any security issued with
respect thereto upon any stock dividend, split or similar event until, in the
case of any such security, (i) it is effectively registered under the Securities
Act and disposed of in accordance with the Registration Statement covering its
offering and sale, (ii) it is saleable by the Holder thereof pursuant to Rule
144(k) or any successor provision or (iii) it is sold to the public pursuant to
Rule 144 and, as a result of the event or circumstance described in any of the
foregoing clauses (i) through (iii), the legends with respect to transfer
restrictions required under the Declaration and the Indenture are removed or
removable in accordance with the terms of the Declaration or the Indenture, as
the case may be.

          Registration Expenses:  See Section 5 hereof.

          Registration Statement: Any registration statement of McKesson or the
Trust which covers any of the Registrable Securities pursuant to the provisions
of this Agreement, including the Prospectus or any other prospectus included
therein, the information, if any, deemed to be a part of such registration
statement pursuant to Rule 430A promulgated under the Securities Act, amendments
and supplements to such registration statement, including post-effective
amendments, all exhibits, and all material incorporated by reference or deemed
to be incorporated by reference in such registration statement.

          Restricted Securities:  As this term is defined in Rule 144.

                                       3
<PAGE>
 
          Rule 144:  Rule 144 under the Securities Act, as such Rule may be
amended from time to time, or any similar rule or regulation hereafter adopted
by the SEC.

          Rule 144A: Rule 144A under the Securities Act, as such Rule may be
amended from time to time, or any similar rule or regulation hereafter adopted
by the SEC.

          SEC: The Securities and Exchange Commission.

          Securities Act: The Securities Act of 1933, as amended, and the rules
and regulations promulgated by the SEC thereunder.

          Selling Period: See Section 2(d)(i) hereof.

          Shelf Registration:  See Section 2(a) hereof.

          Special Counsel: Brown & Wood llp or such other counsel as shall be
specified by the Holders of a majority of the Registrable Securities, the fees
and expenses of which will be paid by McKesson pursuant to Section 5 hereof.

          Subsequent Shelf Registration: See Section 2(b) hereof.

          TIA:  The Trust Indenture Act of 1939, as amended.

          Trustee: The First National Bank of Chicago (or any successor entity),
the Institutional Trustee under the Declaration or, in the event the Convertible
Debentures are distributed to holders of the Convertible Preferred Securities
upon dissolution of the Trust, the Trustee under the Indenture.

          Underlying Common Stock: The Common Stock into which the Convertible
Debentures are convertible.

Section 2.  Shelf Registration.

          a.   Shelf Registration. McKesson and the Trust shall prepare and file
with the SEC on or prior to the 90th day after the latest date of original
issuance of the Convertible Preferred Securities (the 91st day after the latest
date of such original issuance being called the "Filing Date"), a Registration
                                                 -----------                  
Statement for an offering to be made on a delayed or continuous basis pursuant
to Rule 415 of the Securities Act (a "Shelf Registration") registering the
                                      ------------------                  
resale from time to time by Holders thereof of all of the Registrable Securities
(the "Initial Shelf Registration").  The Initial Shelf Registration shall be on
      --------------------------                                               
Form S-3 or another appropriate form permitting registration of such Registrable
Securities for resale by such Holders in the manner or manners designated by
them.  McKesson and the Trust shall use their reasonable best efforts to cause
the Initial Shelf Registration to become effective under the Securities Act as
promptly as is practicable and to keep the Initial Shelf Registration
continuously effective under the Securities Act until the end of the
Effectiveness Period.

                                       4
<PAGE>
 
          b.   If the Initial Shelf Registration or any Subsequent Shelf
Registration, as defined below, ceases to be effective for any reason at any
time during the Effectiveness Period (other than because all Registrable
Securities shall have ceased to be Registrable Securities), McKesson and the
Trust shall use their reasonable best efforts to obtain the prompt withdrawal of
any order suspending the effectiveness thereof, and in any event shall, subject
to Section 2(d), within 30 days of such cessation of effectiveness amend the
Shelf Registration in a manner reasonably expected to obtain the withdrawal of
the order suspending the effectiveness thereof, or file an additional Shelf
Registration covering all of the Registrable Securities (a "Subsequent Shelf
                                                            ----------------
Registration").  If a Subsequent Shelf Registration is filed, McKesson and the
- - ------------                                                                  
Trust shall use their reasonable best efforts to cause the Subsequent Shelf
Registration to become effective as promptly as is practicable after such filing
and to keep such Registration Statement continuously effective until the end of
the Effectiveness Period.

          c.   McKesson and the Trust shall, subject to Section 2(d), supplement
and amend the Shelf Registration if required by the rules, regulations or
instructions applicable to the registration form used by McKesson and the Trust
for such Shelf Registration, if required by the Securities Act.

          d.   Each Holder of Registrable Securities agrees that if such Holder
wishes to sell its Registrable Securities pursuant to a Shelf Registration and
related Prospectus, it will do so only in accordance with this Section 2(d).
Each Holder of Registrable Securities agrees to give written notice to McKesson
and the Trust at least ten (10) Business Days prior to any intended distribution
of Registrable Securities under the Shelf Registration, which notice shall
specify the date on which such Holder intends to begin such distribution and any
information with respect to such Holder and the intended distribution of
Registrable Securities by such Holder required to amend or supplement the
Registration Statement with respect to such intended distribution of Registrable
Securities by such Holder.  As promptly as is practicable after the date such
notice is provided, and in any event within five (5) Business Days after such
date, McKesson and the Trust shall either:

               i.   (A) prepare and file with the SEC a post-effective amendment
to the Shelf Registration or a supplement to the related Prospectus or a
supplement or amendment to any document incorporated therein by reference or
file any other required document so that such Registration Statement will not
contain an untrue statement of a material fact or omit to state a material fact
required to be stated therein or necessary to make the statements therein not
misleading, and so that, as thereafter delivered to purchasers of the
Registrable Securities being sold thereunder, such Prospectus will not contain
an untrue statement of a material fact or omit to state a material fact required
to be stated therein or necessary to make the statements therein, in the light
of the circumstances under which they were made, not misleading; provided that
the Trust and McKesson agree to notify the Holders to suspend use of the
Prospectus, and the Holders shall suspend use of the Prospectus, until the Trust
or McKesson has amended or supplemented the Prospectus so that it does not
contain any such misstatement or omission; (B) provide the Holders of the
Registrable Securities who gave such notice copies of any documents filed
pursuant to Section 2(d)(i)(A); and (C) inform each such Holder that McKesson
and the Trust have complied with their obligations in Section 2(d)(i)(A) and
that the Registration Statement and the Prospectus may be used for sales of

                                       5
<PAGE>
 
Registrable Securities (or that, if McKesson and the Trust have filed a post-
effective amendment to the Shelf Registration which has not yet been declared
effective, McKesson and the Trust will notify each such Holder to that effect,
will use their reasonable best efforts to secure the effectiveness of such post-
effective amendment and will immediately notify each such Holder pursuant to
Section 2(d)(i)(A) hereof when the amendment has become effective and that the
Registration Statement and the Prospectus may be used for sales of Registrable
Securities); each Holder who has given notice of its intention to distribute
such Holder's Registrable Securities in accordance with Section 2(d) hereof (a
"Notice Holder") will sell all or any or such Registrable Securities pursuant to
- - --------------                                                                  
the Shelf Registration and related Prospectus only during the 45-day period
commencing with the date on which McKesson and the Trust give notice, pursuant
to Section 2(d)(i)(A), that the Registration Statement and Prospectus may be
used for such purpose (such 45-day period is referred to as a "Selling Period");
                                                               --------------   
the Notice Holders will not sell any Restricted Securities pursuant to such
Registration Statement or Prospectus after such Selling Period without giving a
new notice of intention to sell pursuant to Section 2(d) hereof and receiving a
further notice from McKesson and the Trust pursuant to Section 2(d)(i)(C)
hereof; or

               ii.  in the event (A) of the happening of any event of the kind
described in Section 2(e)(ii), or (B) that, in the judgment of McKesson, it is
advisable to suspend use of the Prospectus for a discrete period of time due to
pending material corporate developments or similar material events that have not
yet been publicly disclosed and as to which McKesson believes public disclosure
will be prejudicial to McKesson or the Trust, McKesson shall deliver a
certificate in writing, signed by its Chief Executive Officer or Chief Financial
Officer, to the Notice Holders and the Special Counsel to the effect of the
foregoing and, upon receipt of such certificate, each such Notice Holder's
Selling Period will not commence until such Notice Holder's receipt of copies of
the supplemented or amended Prospectus provided for in Section 2(d)(i)(A)
hereof, or until it is advised in writing by McKesson that the Prospectus may be
used, and has received copies of any additional or supplemental filings that are
incorporated or deemed incorporated by reference in such Prospectus.  McKesson
and the Trust will use their reasonable best efforts to ensure that the use of
the Prospectus may be resumed, and the Selling Period will commence, as promptly
as is practicable and, in the case of a pending development or event referred to
in Section 2(d)(ii)(B) hereof, as soon as the earlier of (x) public disclosure
of such pending material corporate development or similar material event or (y)
in the judgment of McKesson, public disclosure of such material corporate
development or similar material event would not be prejudicial to McKesson or
the Trust.  Notwithstanding the foregoing, the period during which a Selling
Period is suspended (a "Deferral Period") shall not exceed 60 days, whether or
                        ---------------                                       
not consecutive, in any 12-month period.

          e.   The parties hereto agree that the Holders of Registrable
Securities will suffer damages, and that it would not be feasible to ascertain
the extent of such damages with precision, if (i) the Initial Shelf Registration
has not been filed prior to the Filing Date, (ii) prior to the end of the
Effectiveness Period, the SEC shall have issued a stop order suspending the
effectiveness of the Shelf Registration or proceedings have been initiated with
respect to the Shelf Registration under Section 8(d) or 8(e) of the Securities
Act or (iii) the aggregate number of days in any permitted Deferral Period
exceeds the number permitted pursuant to Section 2(d)(ii) hereof (each of the
events of a type described in any of the

                                       6
<PAGE>
 
foregoing clauses (i) through (iii) are individually referred to herein as an
"Event," and the Filing Date in the case of clause (i), the date on which the
- - ------                                                                       
effectiveness of the Shelf Registration has been suspended or proceedings with
respect to the Shelf Registration under Section 8(d) or 8(e) of the Securities
Act have been commenced in the case of clause (ii), the date on which the
duration of a Deferral Period exceeds the aggregate number of days permitted by
Section 2(d)(ii) hereof being referred to herein as an "Event Date").  Events
                                                        ----------           
shall be deemed to continue until the "Event Termination Date," which shall be
                                       ----------------------                 
the following dates with respect to the respective types of Events: the date the
Initial Registration Statement is filed in the case of an Event of the type
described in clause (i), the date that all stop orders suspending effectiveness
of the Shelf Registration have been removed and the proceedings initiated with
respect to the Shelf Registration under Section 8(d) or (e) of the Securities
Act have terminated, as the case may be, in the case of Events of the types
described in clause (ii) and termination of the Deferral Period which caused the
limit on the duration of a Deferral Period set forth in Section 2(d)(ii) to be
exceeded in the case of the commencement of an Event of the type described in
clause (iii).

          Accordingly, upon the occurrence of any Event Date and until such time
as there are no Events that have occurred and are continuing (a "Damages Accrual
                                                                 ---------------
Period"), commencing on and including the Event Date on which such Damages
- - ------                                                                    
Accrual Period began, McKesson agrees to pay, as liquidated damages, and not as
a penalty, an additional amount (the "Liquidated Damages Amount"): (i) to each
                                      -------------------------               
Holder of (x) a Convertible Preferred Security or (y) in the event that the
Convertible Debentures are distributed to holders of Convertible Preferred
Securities upon dissolution of the Trust in accordance with the Declaration, a
Convertible Debenture, accruing at a rate equal to one-quarter of one percent
per annum (25 basis points) on an amount equal to the liquidation amount of such
Convertible Preferred Security or principal amount of such Convertible
Debenture, as the case may be, held by such Holder and (ii) to each Holder of
Underlying Common Stock, accruing at a rate equal to one-quarter of one percent
per annum (25 basis points) calculated on an amount equal to the product of (x)
the Applicable Conversion Price as of the Business Day immediately prior to the
applicable Damages Payment Date times (y) the number of shares of Common Stock
that are Registrable Securities held by such Notice Holder.  Notwithstanding the
foregoing, no Liquidated Damages Amounts shall accrue with respect to any
Registrable Security from and after the earlier of (x) the date such security is
no longer a Registrable Security, and (y) expiration of the Effectiveness
Period.  The rate of accrual of the Liquidated Damages Amount with respect to
any period shall not exceed the rate provided for in this paragraph
notwithstanding the occurrence of multiple concurrent Events.  Liquidated
Damages Amounts shall be computed on the basis of a 360-day year of twelve 30-
day months, provided that Liquidated Damages Amounts payable for any period
shorter than a month will be computed on the basis of the actual number of days
elapsed per 30-day month.

          McKesson shall pay the liquidated damages due on any Convertible
Preferred Security, Convertible Debenture or Underlying Common Stock by
depositing with the Trustee, in trust for the benefit of the Holders of
Convertible Preferred Securities or Convertible Debentures entitled thereto (or,
in the case of Underlying Common Stock, by depositing with the transfer agent
for the benefit of the Holders of Underlying Common Stock entitled thereto), as
the case may be, at least one Business Day prior to the applicable Damages
Payment Date, sums sufficient to pay all accrued and unpaid liquidated damages

                                       7
<PAGE>
 
from and including the last Damages Payment Date to which liquidated damages
have been paid in full (or, if no liquidated damages have been paid in respect
of the relevant Damages Accrual Period, from and including the first day of such
Damages Accrual Period) to, but excluding, such Damages Payment Date. The
Liquidated Damages Amount due shall be payable on each Damages Payment Date to
the Holders of Registrable Securities entitled thereto holding such Registrable
Securities on the record date for such Damages Payment Date (which record date,
in the case of Underlying Common Stock, shall be established by McKesson but
shall in any event be between 10 and 60 days prior to the relevant Damages
Payment Date); provided that, if any Convertible Preferred Securities or
Convertible Debentures (or portions thereof) are called for redemption, accrued
and unpaid liquidated damages thereon shall be paid to the person entitled to
receive accrued and unpaid interest thereon; and provided, further, that if any
Convertible Preferred Security or Convertible Debenture (or portion thereof) is
surrendered for conversion from and after the close of business on a regular
record date and prior to the corresponding distribution payment or interest
payment date, as the case may be, then accrued and unpaid liquidated damages
thereon shall be paid to the person entitled to receive accrued and unpaid
distributions or interest, as the case may be, in respect of such Convertible
Preferred Security or Convertible Debenture (or portion thereof), as the case
may be; and provided, further, that if any Convertible Preferred Security or
Convertible Debenture (or portion thereof) is surrendered for conversion at any
other time, then the converting Holder thereof shall be entitled to receive all
accrued and unpaid Liquidated Damages thereon to but excluding the date of
conversion. The Trustee shall be entitled, on behalf of the Notice Holders and
the Holders of Convertible Preferred Securities, Convertible Debentures or
Underlying Common Stock, to seek any available remedy for the enforcement of
this Agreement, including for the payment of such liquidated damages.
Notwithstanding the foregoing, the parties agree that the sole damages payable
for a violation of the terms of this Agreement with respect to which liquidated
damages are expressly provided shall be such liquidated damages.

          All of McKesson's obligations set forth in this Section 2(e) which are
outstanding with respect to any Registrable Security at the time such security
ceases to be a Registrable Security shall survive until such time as all such
obligations with respect to such security have been satisfied in full
(notwithstanding termination of this Agreement pursuant to Section 9(o)).

          The parties hereto agree that the liquidated damages provided for in
this Section 2(e) constitute a reasonable estimate of the damages that may be
incurred by Holders of Registrable Securities (other than the Initial Purchaser)
by reason of the failure of the Shelf Registration to be filed or declared
effective or available (absolutely or as a practical matter) for effecting
resales of Registrable Securities in accordance with the provisions hereof.

Section 3.  Registration Procedures.

          In connection with the registration obligations of McKesson and the
Trust under Section 2 hereof, McKesson and the Trust shall use its reasonable
best efforts to effect such registration to permit the sale of the Registrable
Securities in accordance with the intended method or methods of disposition
thereof, and pursuant thereto McKesson and the Trust shall as soon as reasonably
practicable:

                                       8
<PAGE>
 
          a.   Prepare and file with the SEC a Registration Statement on any
appropriate form under the Securities Act available for the sale of the
Registrable Securities by the Holders thereof in accordance with the intended
method or methods of distribution thereof, and use their reasonable best efforts
to cause each such Registration Statement to become effective and remain
effective as provided herein; provided, that before the effective date of any
such Registration Statement or Prospectus or any amendments or supplements
thereto (other than documents that would be incorporated or deemed to be
incorporated therein by reference and that McKesson or the Trust is required by
applicable securities laws or stock exchange requirements to file) McKesson and
the Trust shall furnish to the Initial Purchaser and the Special Counsel copies
of all such documents proposed to be filed, which documents will be subject to
the review of the Initial Purchaser and the Special Counsel.

          b.   Subject to Section 2(d), prepare and file with the SEC such
amendments and post-effective amendments to each Registration Statement as may
be necessary to keep such Registration Statement continuously effective for the
applicable period specified in Section 2; subject to Section 2(d), cause the
related Prospectus to be supplemented by any required Prospectus supplement, and
as so supplemented to be filed pursuant to Rule 424 (or any similar provisions
then in force) under the Securities Act; and, subject to Section 2(d), comply in
all material respects with the provisions of the Securities Act with respect to
the disposition of all securities covered by such Registration Statement during
the applicable period in accordance with the intended methods of disposition by
the sellers thereof set forth in such Registration Statement as so amended or
such Prospectus as so supplemented.

          c.   Notify the Notice Holders, the Initial Purchaser and the Special
Counsel and (if requested by any such person) confirm such notice in writing,
(i) when a Prospectus, any Prospectus supplement, a Registration Statement or a
post-effective amendment to a Registration Statement has been filed with the
SEC and, with respect to a Registration Statement or any post-effective
amendment, when the same has become effective, (ii) of any request by the SEC or
any other federal or state governmental authority for amendments or supplements
to a Registration Statement or related Prospectus or for additional information,
(iii) of the issuance by the SEC or any other federal or state governmental
authority of any stop order suspending the effectiveness of a Registration
Statement or the initiation or threatening of any proceedings for that purpose,
(iv) of the receipt by McKesson or the Trust of any notification with respect to
the suspension of the qualification or exemption from qualification of any of
the Registrable Securities for sale in any jurisdiction or the initiation or
threatening of any proceeding for such purpose, (v) of the existence of any fact
or happening of any event which makes any statement of a material fact in such
Registration Statement or related Prospectus or any document incorporated or
deemed to be incorporated therein by reference untrue or which would require the
making of any changes in the Registration Statement or Prospectus in order that,
in the case of the Registration Statement, it will not contain any untrue
statement of a material fact or omit to state any material fact required to be
stated therein or necessary to make the statements therein not misleading, and
that, in the case of the Prospectus, it will not contain any untrue statement of
a material fact or omit to state any material fact required to be stated therein
or necessary to make the statements therein, in the light of the circumstances
under which they were made, not misleading, and (vi) of the determination by
McKesson that a post-effective amendment to a Registration Statement would be
appropriate.

                                       9
<PAGE>
 
          d.   Subject to Section 2(d), use their reasonable best efforts to
obtain the withdrawal of any order suspending the effectiveness of a
Registration Statement, or the lifting of any suspension of the qualification
(or exemption from qualification) of any of the Registrable Securities for sale
in any jurisdiction.

          e.   If reasonably requested by the Initial Purchaser, the Special
Counsel or the Holders of a majority of the Registrable Securities being sold
and subject to Section 2(d), (i) include in a Prospectus supplement or post-
effective amendment to a Registration Statement such information as the Initial
Purchaser, Special Counsel, or such Holders, in connection with any offering of
Registrable Securities, agree with the Company and its counsel should be
included therein as required by applicable law, and (ii) make all required
filings of such Prospectus supplement or such post-effective amendment after
McKesson and the Trust have received notification of the matters to be included
in such Prospectus supplement or post-effective amendment; provided, that
McKesson and the Trust shall not be required to take any actions under this
Section 3(e) that are not, in the reasonable opinion of counsel for McKesson, in
compliance with applicable law.

          f.   Furnish to each selling Holder, the Special Counsel and the
Initial Purchaser, without charge, at least one conformed copy of the
Registration Statement and any amendment thereto, including financial statements
but excluding schedules, all documents incorporated or deemed to be incorporated
therein by reference and all exhibits (unless requested in writing by such
Holder, the Special Counsel or the Initial Purchaser).

          g.   Subject to Section 2(d), deliver to each selling Holder, the
Special Counsel and the Initial Purchaser in connection with any offering of
Registrable Securities, without charge, as many copies of the Prospectus or
Prospectuses relating to such Registrable Securities (including each preliminary
prospectus) and any amendment or supplement thereto as such persons may
reasonably request; and, subject to Section 2(d), McKesson and the Trust hereby
consent to the use of each such Prospectus (including each such preliminary
prospectus) and each amendment or supplement thereto by each of the selling
Holders of Registrable Securities in connection with any offering and sale of
the Registrable Securities covered by such Prospectus or any amendment or
supplement thereto.

          h.   Prior to any public offering of Registrable Securities, to
register or qualify or cooperate with the selling Holders and the Special
Counsel in connection with the registration or qualification (or exemption from
such registration or qualification) of such Registrable Securities for offer and
sale under the securities or Blue Sky laws of such jurisdictions within the
United States as any selling Holder reasonably requests in writing; use their
best efforts to keep each such registration or qualification (or exemption
therefrom) effective during the period such Registration Statement is required
to be kept effective; and do any and all other acts or things necessary or
advisable to enable the disposition in such jurisdictions of the Registrable
Securities covered by the applicable Registration Statement; provided, that
neither McKesson nor the Trust will be required to (i) qualify generally to do
business or as a foreign corporation or as a dealer in securities in any
jurisdiction where each would not otherwise be required to so qualify but for
this Section 3(h), (ii) file any general consent to service of process in any
jurisdiction where it is not as of the date hereof so subject or (iii) subject
itself to taxation in any jurisdiction where it is not otherwise so subject.

                                      10
<PAGE>
 
          i.   Cause the Registrable Securities covered by the applicable
Registration Statement to be registered with or approved by such other
governmental agencies or authorities within the United States (except as may be
required solely as a consequence of the nature of such selling Holder, in which
case McKesson and the Trust will cooperate in all reasonable respects with the
filing of such Registration Statement and the granting of such approvals) as may
be necessary to enable the selling Holder or Holders thereof to consummate the
disposition of such Registrable Securities.

          j.   Subject to Section 2(d), during any Selling Period (other than
during a Deferral Period), upon the existence of any fact or the occurrence of
any event as a result of which a Registration Statement shall contain any untrue
statement of a material fact or omit to state any material fact required to be
stated therein or necessary to make the statements therein not misleading, or a
Prospectus shall contain any untrue statement of a material fact or omit to
state any material fact required to be stated therein or necessary to make the
statements therein, in the light of the circumstances under which they were
made, not misleading, prepare and file a post-effective amendment to such
Registration Statement or a supplement to such Prospectus or any document
incorporated therein by reference or file any other required document (such as a
Current Report on Form 8-K) that would be incorporated by reference into the
Registration Statement or such Prospectus, as the case may be, so that such
Registration Statement shall not contain any untrue statement of a material
fact or omit to state any material fact required to be stated therein or
necessary to make the statements therein not misleading, and so that such
Prospectus will not contain any untrue statement of a material fact or omit to
state any material fact required to be stated therein or necessary to make the
statements therein, in the light of the circumstances under which they were
made, not misleading, as thereafter delivered to the purchasers of the
Registrable Securities being sold thereunder, and, in the case of a post-
effective amendment to a Registration Statement, use their reasonable best
efforts to cause it to become effective as promptly as is practicable.

          k.   Enter into such customary agreements which are reasonably
acceptable to the Trust and the Company and take all such other reasonably
requested actions in connection therewith in order to expedite or facilitate the
disposition of such Registrable Securities and in such connection (i) make such
representations and warranties, subject to the ability of McKesson and the Trust
to do so, to the Holders of such Registrable Securities with respect to the
business of McKesson and its subsidiaries and the Trust, the Registration
Statement, Prospectus and documents incorporated by reference or deemed
incorporated by reference, if any, in each case, in form, substance and scope as
shall be reasonably satisfactory to the Special Counsel and the Holders of a
majority of the Registered Securities being sold, and (ii) deliver such
documents and certificates as may be reasonably requested by the Holders of a
majority of the Registrable Securities being sold and the Special Counsel to
evidence the continued validity of the representations and warranties of
McKesson and its subsidiaries and the Trust made pursuant to clause (i) above,
provided, however, that any such documents and certificates that are designated
in writing by McKesson or the Trust, in good faith, as confidential at the time
of delivery of such documents and certificates shall be kept confidential by
such Holders and such Special Counsel unless such disclosure is made in
connection with a court proceeding or required by law, or such information
becomes available to the public generally or through a third party without an
accompanying obligation of confidentiality; and provided, further, that the
foregoing inspection and information gathering shall, to 

                                       11
<PAGE>
 
the greatest extent possible, be coordinated on behalf of the Holders by the
Special Counsel and other parties reasonably acceptable to McKesson and the
Trust. The plan of distribution of the Registration Statement and the Prospectus
included therein shall permit resales of Registrable Securities to be made by
selling security holders through brokers and dealers. However, neither McKesson
nor the Trust will be obligated hereunder to pay the costs and expenses of
opinions of counsel of such selling security holders or accountants' "cold
comfort" letters, and neither the officers and directors of McKesson nor the
trustees of the Trust will be obligated hereunder to participate in marketing
efforts on behalf of such selling securityholders.

          l.   If requested in connection with a disposition of Registrable
Securities pursuant to a Registration Statement, make available for inspection
by a representative of the Holders of Registrable Securities being sold, the
Special Counsel, and any accountant retained by such selling Holders, financial
and other records, pertinent corporate documents and properties of McKesson and
the Trust and its subsidiaries, and cause the executive officers, directors and
employees of the Company and its subsidiaries to supply all information
reasonably requested by any such representative, Special Counsel or accountant
in connection with such disposition; subject to reasonable assurances by each
such person that such information will only be used in connection with matters
relating to such Registration Statement and subject further to the
confidentiality provisions stated in Section 3(k).

          m.   The Company and the Trust shall each use its best efforts to
comply with all applicable rules and regulations of the SEC, and to make
generally available to its security-holders as soon as practicable, but in any
event not later than 18 months after (i) the effective date (as defined in Rule
158(c) under the Securities Act) of the Registration Statement, (ii) the
effective date of each post effective amendment to the Registration Statement,
and (iii) the date of each filing by the Company with the SEC of an Annual
Report on Form 10-K that is incorporated by reference in the Registration
Statement, an earnings statement of the Company and its subsidiaries complying
with Section 11(a) of the Securities Act and the rules and regulations of the
SEC thereunder (including, at the option of the Company, Rule 158).

          n.   Cooperate with the selling Holders of Registrable Securities to
facilitate the timely preparation and delivery of certificates representing
Registrable Securities to be sold and not bearing any restrictive legends; and
enable such Registrable Securities to be in such denominations and registered in
such names as the Holders may request.

          o.   Provide a CUSIP number for all Registrable Securities not later
than the effective date of the Registration Statement and provide the Trustee
and the transfer agent for the Common Stock with printed certificates for the
Registrable Securities which are in a form eligible for deposit with The
Depository Trust Company, as applicable.

          p.   Cause all Underlying Common Stock covered by the Registration
Statement to be listed on each securities exchange or quotation system on which
the Common Stock is then listed no later than the date the Registration
Statement is declared effective and, in connection therewith, to the extent
applicable, to make such filings under the Exchange Act 

                                       12
<PAGE>
 
(e.g., the filing of a Registration Statement on Form 8-A) and to have such
filings declared effective thereunder.

          q.   Cooperate and assist in any filings required to be made with the
National Association of Securities Dealers, Inc.

Section 4.  Holder's Obligations.

          Each Holder, severally and not jointly, agrees, by acquisition of the
Registrable Securities, that such Holder of Registrable Securities shall not be
entitled to sell any of such Registrable Securities pursuant to a Registration
Statement or to receive a Prospectus relating thereto, unless such Holder has
furnished McKesson and the Trust with the notice required pursuant to Section
2(d) hereof (including the information required to accompany such notice) and,
promptly after the request by McKesson and the Trust, such other information
regarding such Holder and the distribution of such Registrable Securities as
McKesson and the Trust may from time to time reasonably request.  McKesson and
the Trust may exclude from such registration the Registrable Securities of any
Holder who does not furnish such information provided above for so long as such
information is not so furnished.  Each Holder of Registrable Securities as to
which any Registration Statement is being effected, severally and not jointly,
agrees promptly to furnish to McKesson and the Trust all information required to
be disclosed in order to make the information previously furnished to McKesson
and the Trust by such Holder not misleading.  Any sale of any Registrable
Securities by any Holder shall constitute a representation and warranty by such
Holder, severally and not jointly, that the information relating to such Holder
and its plan of distribution is as set forth in the Prospectus delivered by such
Holder in connection with such disposition, that such Prospectus does not as of
the time of such sale contain any untrue statement of a material fact relating
to such Holder or its plan of distribution and that such Prospectus does not as
of the time of such sale omit to state any material fact relating to such Holder
or its plan of distribution necessary to make the statements in such Prospectus,
in the light of the circumstances under which they were made, not misleading.

Section 5.  Registration Expenses.

          Subject to the last sentence of Section 3(k) hereof, all fees and
expenses incident to the performance by McKesson and the Trust of or compliance
with this Agreement (the "Registration Expenses") shall be borne by McKesson
whether or not any of the Registration Statements become effective.  Such
Registration Expenses shall include, without limitation, (i) all registration
and filing fees (including, without limitation, fees and expenses (x) with
respect to filings required to be made with the National Association of
Securities Dealers, Inc. and (y) of compliance with federal and state securities
or Blue Sky laws (including, without limitation, fees and disbursements of
Special Counsel in connection with Blue Sky qualifications of the Registrable
Securities under the laws of such jurisdictions as any Holders of Registrable
Securities being sold may designate)), (ii) printing expenses (including,
without limitation, expenses of printing certificates for Registrable Securities
in a form eligible for deposit with The Depositary Trust Company and of printing
Prospectuses), (iii) messenger, telephone and delivery expenses and (iv) fees
and disbursements of counsel for McKesson and the Trust and reasonable fees and
disbursements of the Special Counsel in 

                                       13
<PAGE>
 
connection with the Shelf Registration (provided that McKesson shall not be
liable for the fees and expenses of more than one counsel for all parties
participating in any transaction hereunder). In addition, McKesson shall pay the
internal expenses of McKesson and the Trust (including, without limitation, all
salaries and expenses of officers and employees performing legal or accounting
duties), the expense of any annual audit, the fees and expenses incurred in
connection with the listing of the Underlying Common Stock and the fees and
expenses of any person, including special experts, retained by McKesson or the
Trust. Notwithstanding the provisions of this Section 5, each seller of
Registrable Securities shall pay all individual selling expenses of such seller,
including such seller's brokers' commissions.

Section 6.  Indemnification; Contribution.

          a.   Indemnification by McKesson.  McKesson and the Trust, jointly and
severally, agree to indemnify and hold harmless each Holder and each person, if
any, who controls any Holder within the meaning of either Section 15 of the
Securities Act or Section 20 of the Exchange Act from and against any and all
losses, claims, damages and liabilities (including, without limitation, any
legal or other expenses reasonably incurred in connection with defending or
investigating any such action or claim) caused by (i) any untrue statement or
alleged untrue statement of a material fact contained in any Registration
Statement or any amendment thereof, including all documents incorporated therein
by reference, or the omission or alleged omission therefrom of a material fact
required to be stated therein or necessary to make the statements therein not
misleading or (ii) any untrue statement or alleged untrue statement of a
material fact contained in any preliminary prospectus or any Prospectus (or
amendment or supplement thereto) or the omission or alleged omission therefrom
of a material fact necessary in order to make the statements therein, in the
light of the circumstances under which they were made, not misleading; except
insofar as such losses, claims, damages or liabilities are caused by any such
untrue statement or omission or alleged untrue statement or omission based upon
information relating to any Holder furnished to McKesson and the Trust in
writing by such Holder expressly for use therein.  McKesson and the Trust,
jointly and severally, shall also indemnify each broker-dealer participating in
the offering and sale of Registrable Securities and each person who controls any
such broker-dealer (within the meaning of Section 15 of the Securities Act or
Section 20 of the Exchange Act) to the same extent and with the same limitations
as provided above with respect to the indemnification of the Holders of
Registrable Securities.

          The foregoing notwithstanding, the Trust and McKesson shall not be
liable to the extent that such losses, claims, damages or liabilities arise out
of or are based upon an untrue statement or alleged untrue statement or omission
or alleged omission made in any Prospectus that is a preliminary prospectus if
(i) such indemnified person failed to send or deliver a copy of the Prospectus
with or prior to the delivery of written confirmation of the sale of Registrable
Securities giving rise to such losses, claims, damages or liabilities and (ii)
the Prospectus would have corrected such untrue statement or omission.

          b.   Indemnification by Holder of Registrable Securities.  Each Holder
agrees, severally and not jointly, to indemnify and hold harmless McKesson and
the Trust, McKesson's directors, McKesson's officers who sign a Registration
Statement, the MFT 

                                       14
<PAGE>
 
Trustees, and each person, if any, who controls McKesson or the Trust within the
meaning of either Section 15 of the Securities Act or Section 20 of the Exchange
Act from and against any and all losses, claims, damages and liabilities
(including, without limitation, any legal or other expenses reasonably incurred
in connection with defending or investigating any such action or claim) caused
by any untrue statement or alleged untrue statement of a material fact contained
in any Registration Statement or any amendment thereof, any preliminary 
prospectus or any Prospectus (as amended or supplemented if the Company shall
have furnished any amendments or supplements thereto), or caused by any omission
or alleged omission to state therein a material fact required to be stated
therein or necessary to make the statements therein not misleading, but only
with reference to information relating to such Holder furnished to the Company
and the Trust in writing by such Holder expressly for use in such Registration
Statement, preliminary prospectus, Prospectus or any amendments or supplements
thereto. In no event shall the liability of any Holder of Registrable Securities
hereunder be greater in amount than the net dollar amount of the proceeds
received by such Holder from the sale of the Registrable Securities giving rise
to such indemnification obligation.

          c.   Conduct of Indemnification Proceedings.  In case any proceeding
(including any governmental investigation) shall be instituted involving any
person in respect of which indemnity may be sought pursuant to either of the two
preceding paragraphs, such person (the "indemnified party") shall promptly
                                        -----------------                 
notify the person against whom such indemnity may be sought (the "indemnifying
                                                                  ------------
party") in writing and the indemnifying party, upon request of the indemnified
- - -----                                                                         
party, shall retain counsel reasonably satisfactory to the indemnified party to
represent the indemnified party and any others the indemnifying party may
designate in such proceeding and shall pay the reasonable fees and disbursements
of such counsel related to such proceeding.  In any such proceeding, any
indemnified party shall have the right to retain its own counsel, but the fees
and expenses of such counsel shall be at the expense of such indemnified party
unless (i) the indemnifying party and the indemnified party shall have mutually
agreed to the retention of such counsel or (ii) the named parties to any such
proceeding (including any impleaded parties) include both the indemnifying party
and the indemnified party and representation of both parties by the same counsel
would be inappropriate due to actual or potential differing interests between
them.  It is understood that the indemnifying party shall not, in respect of the
legal expenses of any indemnified party in connection with any proceeding or
related proceedings in the same jurisdiction, be liable for (a) the fees and
expenses of more than one separate firm (in addition to any local counsel) for
all Holders and all persons, if any, who control any Holders within the meaning
of either Section 15 of the Securities Act or Section 20 of the Exchange Act,
and (b) the fees and expenses of more than one separate firm (in addition to any
local counsel) for McKesson and the Trust and each person, if any, who controls
McKesson or the Trust within the meaning of either such Section, and that all
such fees and expenses shall be reimbursed as they are incurred.  In the case of
any such separate firm for McKesson and the Trust and any such control persons
of McKesson or the Trust, such firm shall be designated in writing by McKesson.
In the case of any such separate firm for the Holders or any such control
persons of any Holders, such firm shall be designated in writing on behalf of
the Holders of a majority of the relevant Registrable Securities.  The
indemnifying party shall not be liable for any settlement of any proceeding
effected without its written consent, but if settled with such consent or if
there be a final judgment for the plaintiff, the indemnifying party agrees to

                                       15
<PAGE>
 
indemnify the indemnified party from and against any loss or liability by reason
of such settlement or judgment.  Notwithstanding the foregoing sentence, if at
any time an indemnified party shall have requested an indemnifying party to
reimburse the indemnified party for fees and expenses of counsel as contemplated
by the second and third sentences of this paragraph, the indemnifying party
agrees that it shall be liable for any settlement of any proceeding effected
without its written consent if (i) such settlement is entered into more than 30
days after receipt by such indemnifying party of the aforesaid request and (ii)
such indemnifying party shall not have reimbursed the indemnified party in
accordance with such request prior to the date of such settlement. No
indemnifying party shall, without the prior written consent of the indemnified
party, effect any settlement of any pending or threatened proceeding in respect
of which any indemnified party is or could have been a party and indemnity could
have been sought hereunder by such indemnified party, unless such settlement
includes an unconditional release of such indemnified party from all liability
on claims that are the subject matter of such proceeding.

          d.   Contribution.  To the extent the indemnification provided for in
paragraph (a) or (b) of this Section 6 is unavailable to an indemnified party or
insufficient in respect of any losses, claims, damages or liabilities referred
to herein, then each indemnifying party shall contribute to the amount paid or
payable by such indemnified party as a result of such losses, claims, damages or
liabilities (or actions in respect thereof) in such proportion as is appropriate
to reflect the relative fault of the indemnifying party and the indemnified
party in connection with the statements or omissions which resulted in such
losses, claims, damages or liabilities (or actions in respect thereof), as well
as any other relevant equitable considerations.  The relative fault of such
indemnifying party and indemnified party shall be determined by reference to,
among other things, whether the untrue or alleged untrue statement of a material
fact or omission or alleged omission to state a material fact relates to
information supplied by such indemnifying party or by such indemnified party,
and the parties' relative intent, knowledge, access to information and
opportunity to correct or prevent such statement or omission.  The Holders'
respective obligations to contribute pursuant to this paragraph are several in
proportion to the respective number of Registrable Securities they have sold
pursuant to a Registration Statement, and not joint.

          e.   The Company, the Trust and the Holders agree that it would not be
just or equitable if contribution pursuant to Section 6(d) were determined by
pro rata allocation or by any other method of allocation that does not take
account of the equitable considerations referred to in paragraph (d) of this
Section 6.  The amount paid or payable by an indemnified party as a result of
the losses, claims, damages or liabilities referred to in paragraph (d) of this
Section 6 shall be deemed to include, subject to the limitations set forth
above, any legal or other expenses reasonably incurred by such indemnified party
in connection with investigating or defending any such action or claim.
Notwithstanding the provisions of this Section 6, a Holder of Registrable
Securities shall not be required to contribute any amount in excess of the
amount by which the total price at which the Registrable Securities sold by such
indemnifying party and distributed to the public were offered to the public
pursuant to any Registration Statement exceeds the amount of any damages which
such indemnifying party has otherwise been required to pay by reason of such
untrue or alleged untrue statement or omission or alleged omission.  No person
guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of
the Securities Act) shall be entitled to contribution from any 

                                       16
<PAGE>
 
person who was not guilty of such fraudulent misrepresentation. The remedies
provided for in this Section 6 are not exclusive and shall not limit any rights
or remedies which may otherwise be available to any indemnified party at law or
in equity.

          f.   The indemnity and contribution provisions contained in this
Section 6 shall remain operative and in full force and effect regardless of (i)
any termination of this Agreement, (ii) any investigation made by or on behalf
of any Holder or any person controlling any Holder, or McKesson or the Trust or
any person controlling McKesson or the Trust and (iii) the sale of any
Registrable Securities by any Holder.

Section 7.  Information Requirements.

          a.   McKesson and the Trust shall file the reports required to be
filed by it under the Securities Act and the Exchange Act, and if at any time
McKesson or the Trust is not required to file such reports, it will, upon the
reasonable request of any Holder of Registrable Securities, make publicly
available other information so long as necessary to permit sales of Registrable
Securities pursuant to Rule 144 and Rule 144A under the Securities Act. Upon the
request of any Holder of Registrable Securities, each of McKesson and the Trust
shall deliver to such Holder a written statement as to whether it has complied
with such filing requirements. McKesson and the Trust further covenant that they
will cooperate with any Holder of Registrable Securities and take such further
reasonable action as any Holder of Registrable Securities may reasonably request
(including, without limitation, making such reasonable representations as any
such Holder may reasonably request), all to the extent required from time to
time to enable such Holder to sell Registrable Securities without registration
under the Securities Act within the limitation of the exemptions provided by
Rule 144 and Rule 144A under the Securities Act. Notwithstanding the foregoing,
nothing in this Section 7 shall be deemed to require McKesson or the Trust to
register any of its securities (other than the Common Stock) under any section
of the Exchange Act.

          b.   McKesson and the Trust shall file the reports required to be
filed by it under the Exchange Act and shall use its best efforts to comply with
all other requirements set forth in the instructions to Form S-3 in order to
allow it to be eligible to file registration statements on Form S-3.

                                       17
<PAGE>
 
Section 8.  Governing Law

          THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH
THE LAWS OF THE STATE OF NEW YORK, AS APPLIED TO CONTRACTS MADE AND PERFORMED
WITHIN THE STATE OF NEW YORK, WITHOUT REGARD TO PRINCIPLES OF CONFLICTS OF LAW.
EACH OF THE PARTIES HERETO HEREBY IRREVOCABLY SUBMITS TO THE JURISDICTION OF ANY
NEW YORK STATE COURT SITTING IN THE BOROUGH OF MANHATTAN IN THE CITY OF NEW YORK
OR ANY FEDERAL COURT SITTING IN THE BOROUGH OF MANHATTAN IN THE CITY OF NEW YORK
IN RESPECT OF ANY SUIT, ACTION OR PROCEEDING ARISING OUT OF OR RELATING TO THIS
AGREEMENT, AND IRREVOCABLY ACCEPTS FOR ITSELF AND IN RESPECT OF ITS PROPERTY,
GENERALLY AND UNCONDITIONALLY, THE JURISDICTION OF THE AFORESAID COURTS.  EACH
OF THE PARTIES HERETO IRREVOCABLY WAIVES, TO THE FULLEST EXTENT IT MAY
EFFECTIVELY DO SO UNDER APPLICABLE LAW, ANY OBJECTION THAT IT MAY NOW OR
HEREAFTER HAVE TO THE LAYING OF THE VENUE OF ANY SUCH SUIT, ACTION OR PROCEEDING
BROUGHT IN ANY SUCH COURT AND ANY CLAIM THAT ANY SUCH SUIT, ACTION OR PROCEEDING
BROUGHT IN ANY SUCH COURT HAS BEEN BROUGHT IN AN INCONVENIENT FORUM.

Section 9.  Miscellaneous

          a.   No Conflicting Agreements. Neither McKesson nor the Trust has, as
of the date hereof, entered into, nor shall McKesson or the Trust, on or after
the date of this Agreement, enter into, any agreement with respect to its
securities which conflicts with the rights granted to the Holders of Registrable
Securities in this Agreement. Each of McKesson and the Trust represents and
warrants that the rights granted to the Holders of Registrable Securities
hereunder do not in any way conflict with the rights granted to the Holders of
McKesson's or the Trust's securities under any other agreements.

          b.   Amendments and Waivers.  The provisions of this Agreement,
including the provisions of this sentence, may not be amended, modified or
supplemented, and waivers or consents to departures from the provisions hereof
may not be given, unless McKesson and the Trust have obtained the written
consent of Holders of a majority of the then outstanding Underlying Common Stock
constituting Registrable Securities (with Holders of Convertible Preferred
Securities deemed to be the Holders, for purposes of this Section, of the number
of outstanding shares of Underlying Common Stock into which such Convertible
Preferred Securities are convertible or exchangeable or, in the event that the
Convertible Debentures have been distributed to Holders upon liquidation of the
Trust, with the Holders of Convertible Debentures deemed to be the Holders, for
purpose of this Section, the number of outstanding shares of Underlying Common
Stock into which such Convertible Debentures are convertible).  Notwithstanding
the foregoing, a waiver or consent to depart from the provisions hereof with
respect to a matter that relates exclusively to the rights of Holders of
Registrable Securities whose securities are being sold pursuant to a
Registration Statement and that does not directly or indirectly affect the
rights of other Holders of Registrable Securities may be given by Holders of at
least a majority of the Registrable Securities being

                                       18
<PAGE>
 
sold by such Holders; provided, that the provisions of this sentence may not be
amended, modified, or supplemented except in accordance with the provisions of
the immediately preceding sentence.

          c.   Notices.  All notices and other communications provided for or
permitted hereunder shall be made in writing and shall be deemed given (i) when
made, if made by hand delivery, (ii) upon confirmation, if made by telecopier,
(iii) one (1) Business Day after being deposited with a reputable next-day
courier, postage prepaid, or (iv) three (3) Business Days after being deposited
with the United States Postal Service, with first-class postage prepaid to the
parties as follows:

          (A)  if to a Holder of Registrable Securities, at the most current
     address given by such Holder to McKesson and the Trust in accordance with
     the provisions of Section 9(e);

          (B)  if to McKesson, to:

               McKesson Corporation
               McKesson Plaza
               One Post Street
               San Francisco, California  94104
               Attention:  General Counsel
               Telecopy:  (415) 983-8826

          (C)  if to the Trust, to:

               McKesson Financing Trust
               c/o McKesson Corporation
               McKesson Plaza
               One Post Street
               San Francisco, California  94104
               Attention:  General Counsel
               Telecopy:  (415) 983-8826

               and

          (D)  if to the Special Counsel, to:

               Brown & Wood llp
               555 California Street
               San Francisco, California  94104
               Attention:  Paul C. Pringle
                           Eric S. Haueter
               Telecopy:  (415) 397-4621

                                       19
<PAGE>
 
or to such other address as such person may have furnished to the other persons
identified in this Section 9(d) in writing in accordance herewith.

          d.   Owner of Registrable Securities.  McKesson and the Trust will
maintain, or will cause its registrar and transfer agent to maintain, a register
with respect to the Registrable Securities in which all transfers of Registrable
Securities of which McKesson or the Trust has received notice will be recorded.
McKesson and the Trust may deem and treat the person in whose name Registrable
Securities are registered in such register of McKesson and the Trust as the
owner thereof for all purposes, including, without limitation, the giving of
notices under this Agreement.

          e.   Approval of Holders.  Whenever the consent or approval of Holders
of a specified percentage of Registrable Securities is required hereunder,
Registrable Securities held by McKesson, the Trust or their respective
affiliates (as such term is defined in Rule 405 under the Securities Act) (other
than the Initial Purchaser or subsequent Holders of Registrable Securities if
such subsequent Holders are deemed to be such affiliates solely by reason of
their holdings of such Registrable Securities) shall not be counted in
determining whether such consent or approval was given by the Holders of such
required percentage.

          f.   Successors and Assigns.  Any person who purchases any Registrable
Securities from the Initial Purchaser shall be deemed, for purposes of this
Agreement, to be an assignee of such Initial Purchaser.  This Agreement shall
inure to the benefit of and be binding upon the successors and assigns of each
of the parties and shall inure to the benefit of and be binding upon each Holder
of any Registrable Securities.

          g.   Counterparts.  This Agreement may be executed in any number of
counterparts and by the parties hereto in separate counterparts, each of which
when so executed shall be deemed to be original and all of which taken together
shall constitute one and the same agreement.

          h.   Headings.  The headings in this Agreement are for convenience of
reference only and shall not limit or otherwise affect the meaning hereof.

          i.   Governing Law.  THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED
IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK, AS APPLIED TO CONTRACTS
MADE AND PERFORMED WITHIN THE STATE OF NEW YORK, WITHOUT REGARD TO PRINCIPLES OF
CONFLICT OF LAWS.

          j.   Severability.  If any term, provision, covenant or restriction of
this Agreement is held to be invalid, illegal, void or unenforceable, the
remainder of the terms, provisions, covenants and restrictions set forth herein
shall remain in full force and effect and shall in no way be affected, impaired
or invalidated thereby, and the parties hereto shall use their best efforts to
find and employ an alternative means to achieve the same or substantially the
same result as that contemplated by such term, provision, covenant or
restriction.  It is hereby stipulated and declared to be the intention of the
parties that they would have executed the remaining terms, provisions, covenants
and restrictions without including any of such which may be hereafter declared
invalid, void or unenforceable.

                                       20
<PAGE>
 
          k.   Entire Agreement.  This Agreement is intended by the parties as a
final expression of their agreement and is intended to be a complete and
exclusive statement of the agreement and understanding of the parties hereto in
respect of the subject matter contained herein and the registration rights
granted by McKesson and the Trust with respect to the Registrable Securities
sold pursuant to the Placement Agreement. Except as provided in the Placement
Agreement, there are no restrictions, promises, warranties or undertakings,
other than those set forth or referred to herein, with respect to the
registration rights granted by McKesson and the Trust with respect to the
Registrable Securities. This Agreement supersedes all prior agreements and
undertakings among the parties with respect to such registration rights.

          l.   Termination.  This Agreement and the obligations of the parties
hereunder shall terminate upon the end of the Effectiveness Period, except for
any liabilities or obligations under Sections 4, 5 or 6 hereof and the
obligations to make payments of and provide for liquidated damages under Section
2(e) hereof to the extent such damages accrue prior to the end of the
Effectiveness Period, each of which shall remain in effect in accordance with
their terms.

          m.   Joint and Several Obligations.  Anything herein to the contrary
notwithstanding, the representations, warranties, covenants and agreements of
McKesson and the Trust contained in this Agreement are joint and several, other
than the obligations under Section 5 hereof.

          n.   Majority Holders.  To the extent that this Agreement provides for
any action, decision or determination to be taken or made by Holders of a
majority of all the Registrable Securities or by Holders of a majority of
certain Registrable Securities, then the determination of such majority holders
shall be made in the same manner as is specified in Section 9(c).

                                       21
<PAGE>
 
          IN WITNESS WHEREOF, the parties have executed this Agreement as of the
date first written above.

                                             McKESSON CORPORATION


                                             By:  /s/ Ivan D. Meyerson
                                                  -----------------------------
                                                  Name:  Ivan D. Meyerson
                                                  Title:  Vice President

                                             McKESSON FINANCING TRUST


                                             By:  /s/ William A. Armstrong
                                                  -----------------------------
                                                  Name:  William A. Armstrong
                                                  Title:  Trustee
                                                  Solely as trustee and not in 
                                                  his individual capacity


Accepted as of the date first
above written,

MORGAN STANLEY & CO. INCORPORATED


By:  /s/ Gordon G. Dean
     ---------------------------
     Name:  Gordon G. Dean
     Title:  Managing Director

<PAGE>
 
                                                                    EXHIBIT 12.1
 
               COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES
 
<TABLE>
<CAPTION>
                                                                 NINE MONTHS
                            FISCAL YEAR ENDED MARCH 31,      ENDED DECEMBER 31,
                         ----------------------------------- --------------------
                          1996   1995    1994   1993   1992    1996       1995
                         ------ ------  ------ ------ ------ ---------  ---------
<S>                      <C>    <C>     <C>    <C>    <C>    <C>        <C>
Income (loss) before
 income taxes...........  196.9  (53.5)  114.3  109.0   26.4     (23.2)     139.7
Fixed charges (1).......   53.1   52.8    47.3   55.2   59.2      40.8       41.1
                         ------ ------  ------ ------ ------ ---------  ---------
  Total earnings and
   fixed charges........  250.0   (0.7)  161.6  164.2   85.6      17.6      180.8
Fixed charges (1).......   53.1   52.8    47.3   55.2   59.2      40.8       41.1
Ratio of earnings to
 fixed charges (2)......   4.71  (0.01)   3.42   2.97   1.45      0.43       4.40
                         ------ ------  ------ ------ ------ ---------  ---------
</TABLE>
- - --------
(1) Fixed charges consist of interest expense incurred and the portion of
    rental expense under operating leases deemed by the Company to be
    representative of the interest factor.
(2) Earnings were inadequate to cover fixed charges by $0.7 million for fiscal
    1995.

<PAGE>
 
                                                                   EXHIBIT 23.2
 
                         INDEPENDENT AUDITORS' CONSENT
 
We consent to the incorporation by reference in this Registration Statement of
McKesson Corporation ("McKesson") on Form S-3 of our reports dated May 13,
1996 (December 31, 1996 as to Notes 8 and 17) on McKesson's consolidated
financial statements (which report expresses an unqualified opinion and
includes an explanatory paragraph relating to a change in the Company's method
of accounting for post employment benefits to conform with Statement of
Financial Accounting Standards No. 112) and our report dated May 13, 1996
(December 31, 1996 as to Notes 8 and 17) on McKesson's consolidated
supplementary financial schedule, both such reports appearing in the Annual
Report on Form 10-K/A of McKesson Corporation for the year ended March 31,
1996, and our report on FoxMeyer Corporation consolidated financial statements
dated June 28, 1996 (March 18, 1997 as to paragraph seven of Note Q), which
report expresses an unqualified opinion and includes an explanatory paragraph
relating to the sale of the principal assets of FoxMeyer Corporation and its
Chapter 7 bankruptcy filing, appearing in the Current Report on Form 8-K/A of
McKesson Corporation filed with the Securities and Exchange Commission on
April 28, 1997. We also consent to the reference to us under the heading
"Experts" in the Prospectus, which is part of this Registration Statement.
 
s/ DELOITTE & TOUCHE LLP
 
San Francisco, California
Dallas, Texas
 
May 2, 1997

<PAGE>
 
                                                                      Exhibit 24
                                                                      ----------

                               POWER OF ATTORNEY


          Each of the undersigned directors and each of the undersigned officers
of McKesson Corporation, a Delaware corporation (the "Company"), does hereby
constitute and appoint Mark A. Pulido, Richard H. Hawkins, Ivan D. Meyerson and
Nancy A. Miller, and each of them, as his or her true and lawful attorneys-in-
fact and agents, with full power of substitution and resubstitution, for him or
her and in his or her name, place and stead in any and all capacities, to
execute and deliver in his or her name and on his or her behalf:

          (a) one or more Registration Statements (with all exhibits
     thereto) of the Company on Form S-3 or any other appropriate form
     proposed to be filed by the Company with the Securities and
     Exchange Commission (the "SEC"), (including, without limitation,
     Registration Statements filed pursuant to Rule 462(b) under the
     Securities Act of 1933, as amended, or any successor thereto (the
     "Securities Act")), for the purpose of registering under the
     Securities Act, the Company's 5% Trust Securities (the "Trust
     Securi ties"), the guarantees executed by McKesson for the
     benefit of the holders from time to time of the Trust Securities,
     the Company's 5% Convertible Junior Subordinated Debentures (the
     "Convertible Debentures") and the Company's common stock, par
     value $0.01 per share, issuable upon conversion of the
     Convertible Debentures (collectively, the "Registrable
     Securities");

          (b) any and all supplements and amendments (including,
     without limitation, post-effective amendments) to such
     Registration Statements; and

          (c) any and all other documents and instruments in connection with the
     registration of the Registrable Securities which such attorneys-in-fact and
     agents, or any one of them, deem necessary or advisable to enable the
     Company to comply with (i) the Securities Act, the Securities Exchange Act
     of 1934, as amended, and the other federal securities laws of the United
     States of America and the rules, regulations and  require-

                                       1
<PAGE>
 
     ments of the SEC in respect of any thereof; (ii) the securities or Blue Sky
     laws of any state or other governmental subdivision of the United States of
     America; and (iii) the securities or similar applicable laws of any foreign
     jurisdiction;

and each of the undersigned hereby grants unto such attorneys-in-fact and
agents, and each of them, or his or her substitute or substitutes, each and
every act and thing requisite and necessary to be done in and about the premises
as fully as to all intents and purposes as he or she might or could do in
person, and does hereby ratify and confirm as his or her own acts and deeds all
that such attorneys-in-fact and agents, and each of them, or his or her
substitute or substitutes, shall lawfully do or cause to be done by virtue
hereof. Each one of such attorneys-in-fact and agents shall have, and may
exercise, all of the powers hereby conferred.

          IN WITNESS WHEREOF, the undersigned has hereunto sub scribed this
power of attorney this 26th day of March 1997.



/s/Alan Seelenfreund                       /s/ John M. Pietruski
- - --------------------------------------     -------------------------------------
Alan Seelenfreund                          John M. Pietruski
                                      
                                      
/s/Mark A. Pulido                          /s/ Carl E. Reichardt         
- - --------------------------------------     -------------------------------------
Mark A. Pulido                             Carl E. Reichardt
                                      
                                      
/s/ Mary G.F. Bitterman                    /s/ Jane E. Shaw
- - --------------------------------------     -------------------------------------
Mary G. F. Bitterman                       Jane E. Shaw
                                      
                                      
/s/ Tully M. Friedman                      /s/Robert H. Waterman, Jr.
- - --------------------------------------     -------------------------------------
Tully M. Friedman                          Robert H. Waterman, Jr.


/s/ Heidi E. Yodowitz                      /s/ Richard H. Hawkins
- - --------------------------------------     -------------------------------------
Heidi E. Yodowitz                          Richard H. Hawkins

                                       2

<PAGE>
 
                                                                    Exhibit 25.1

                      SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C. 20549

                                   FORM T-1
                                   --------

                           STATEMENT OF ELIGIBILITY
                     UNDER THE TRUST INDENTURE ACT OF 1939
                 OF A CORPORATION DESIGNATED TO ACT AS TRUSTEE

               CHECK IF AN APPLICATION TO DETERMINE ELIGIBILITY
               OF A TRUSTEE PURSUANT TO SECTION 305(B)(2) _____

                       _________________________________

                      THE FIRST NATIONAL BANK OF CHICAGO
              (EXACT NAME OF TRUSTEE AS SPECIFIED IN ITS CHARTER)

  A NATIONAL BANKING ASSOCIATION                          36-0899825
                                                      (I.R.S. EMPLOYER
                                                    IDENTIFICATION NUMBER)

ONE FIRST NATIONAL PLAZA, CHICAGO, ILLINOIS               60670-0126
   (ADDRESS OF PRINCIPAL EXECUTIVE OFFICES)               (ZIP CODE)

                      THE FIRST NATIONAL BANK OF CHICAGO
                     ONE FIRST NATIONAL PLAZA, SUITE 0286
                        CHICAGO, ILLINOIS 60670-0286
            ATTN:  LYNN A. GOLDSTEIN, LAW DEPARTMENT (312) 732-6919
           (NAME, ADDRESS AND TELEPHONE NUMBER OF AGENT FOR SERVICE)

                      ___________________________________

                             MCKESSON CORPORATION
              (EXACT NAME OF OBLIGOR AS SPECIFIED IN ITS CHARTER)


          DELAWARE                                        36-6784329
 (STATE OR OTHER JURISDICTION OF                      (I.R.S. EMPLOYER
 INCORPORATION OR ORGANIZATION)                    IDENTIFICATION NUMBER)

 
     MCKESSON PLAZA
     ONE POST STREET
     SAN FRANCISCO, CALIFORNIA                            94104
(ADDRESS OF PRINCIPAL EXECUTIVE OFFICES)                (ZIP CODE)

            5% CONVERTIBLE JUNIOR SUBORDINATED DEBENTURES DUE 2027
                        (TITLE OF INDENTURE SECURITIES)

                                       1
<PAGE>
 
ITEM 1.   GENERAL INFORMATION.  FURNISH THE FOLLOWING
          --------------------                       
               INFORMATION AS TO THE TRUSTEE:

               (A) NAME AND ADDRESS OF EACH EXAMINING OR
               SUPERVISING AUTHORITY TO WHICH IT IS SUBJECT.

               Comptroller of Currency, Washington, D.C.,
               Federal Deposit Insurance Corporation,
               Washington, D.C., The Board of Governors of
               the Federal Reserve System, Washington D.C.

               (B) WHETHER IT IS AUTHORIZED TO EXERCISE
               CORPORATE TRUST POWERS.

               The trustee is authorized to exercise corporate
               trust powers.

ITEM 2.   AFFILIATIONS WITH THE OBLIGOR.  IF THE OBLIGOR
          ------------------------------                
               IS AN AFFILIATE OF THE TRUSTEE, DESCRIBE EACH
               SUCH AFFILIATION.

               No such affiliation exists with the trustee.

 
ITEM 16.       LIST OF EXHIBITS.   LIST BELOW ALL EXHIBITS FILED AS A
               -----------------                                     
               PART OF THIS STATEMENT OF ELIGIBILITY.

               1.  A copy of the articles of association of the
                   trustee now in effect.*

               2.  A copy of the certificates of authority of the
                   trustee to commence business.*

               3.  A copy of the authorization of the trustee to
                   exercise corporate trust powers.*

               4.  A copy of the existing by-laws of the trustee.*

               5.  Not Applicable.

               6.  The consent of the trustee required by
                   Section 321(b) of the Act.

                                       2
<PAGE>
 
          7. A copy of the latest report of condition of the
             trustee published pursuant to law or the
             requirements of its supervising or examining
             authority.

          8. Not Applicable.

          9. Not Applicable.


     Pursuant to the requirements of the Trust Indenture Act of 1939, as
     amended, the trustee, The First National Bank of Chicago, a national
     banking association organized and existing under the laws of the United
     States of America, has duly caused this Statement of Eligibility to be
     signed on its behalf by the undersigned, thereunto duly authorized, all in
     the City of Chicago and State of Illinois, on the 8th day of April, 1997.


                    THE FIRST NATIONAL BANK OF CHICAGO,
                    TRUSTEE

                    BY   /S/ RICHARD D. MANELLA

                         RICHARD D. MANELLA
                         VICE PRESIDENT



* EXHIBITS 1, 2, 3 AND 4 ARE HEREIN INCORPORATED BY REFERENCE TO EXHIBITS
BEARING IDENTICAL NUMBERS IN ITEM 16 OF THE FORM T-1 OF THE FIRST NATIONAL BANK
OF CHICAGO, FILED AS EXHIBIT 25.1 TO THE REGISTRATION STATEMENT ON FORM S-3 OF
SUNAMERICA INC. FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON OCTOBER 25,
1996 (REGISTRATION NO. 333-14201).

                                       3
<PAGE>
 
                                   EXHIBIT 6



                      THE CONSENT OF THE TRUSTEE REQUIRED
                         BY SECTION 321(b) OF THE ACT


                                 April 8, 1997
 


Securities and Exchange Commission
Washington, D.C.  20549

Gentlemen:

In connection with the qualification of an indenture between McKesson
Corporation and The First National Bank of Chicago, the undersigned, in
accordance with Section 321(b) of the Trust Indenture Act of 1939, as amended,
hereby consents that the reports of examinations of the undersigned, made by
Federal or State authorities authorized to make such examinations, may be
furnished by such authorities to the Securities and Exchange Commission upon its
request therefor.


                         Very truly yours,

                         THE FIRST NATIONAL BANK OF CHICAGO
 
                         BY:  /S/ RICHARD D. MANELLA
 
                              RICHARD D. MANELLA
                              VICE PRESIDENT

                                       4
<PAGE>
 
                                   EXHIBIT 7

 
Legal Title of Bank:    The First National Bank of Chicago  Call Date: 09/30/96
Address:                One First National Plaza, Ste 0460    ST-BK:  17-1630 
City, State  Zip:       Chicago, IL  60670                  FFIEC 031 Page RC-1 
FDIC Certificate No.:   0/3/6/1/8
                        ---------


CONSOLIDATED REPORT OF CONDITION FOR INSURED COMMERCIAL
AND STATE-CHARTERED SAVINGS BANKS FOR SEPTEMBER 30, 1996

All schedules are to be reported in thousands of dollars. Unless otherwise
indicated, report the amount outstanding of the last business day of the
quarter.

SCHEDULE RC--BALANCE SHEET

<TABLE> 
<CAPTION> 
                                                             DOLLAR AMOUNTS IN                     C400           Less than
                                                                                                 ------------     ----------
                                                                  THOUSANDS            RCFD      BIL MIL THOU
                                                             -----------------         ----      ------------
 
ASSETS
<S>                                                          <C>                       <C>        <C>             <C> 
1.  Cash and balances due from depository institutions 
    (from Schedule RC-A):
    a. Noninterest-bearing balances and currency
    and coin(1)..............................................                           0081      4,041,784         1.a.      
    b. Interest-bearing balances(2)..........................                           0071      5,184,890         1.b.      
2.  Securities                                                                                                                
    a. Held-to-maturity securities(from Schedule                                                                              
    RC-B, column A).........................................                            1754              0         2.a. 
    b. Available-for-sale securities (from                                                                                    
    Schedule RC-B, column D)................................                            1773      3,173,481         2.b.       
3.  Federal funds sold and securities purchased under 
    agreements to resell in domestic offices
    of the bank and its Edge and Agreement subsidiaries, 
    and in IBFs:
    a. Federal Funds sold...................................                            0276      3,505,874         3.a.
    b. Securities purchased under agreements to resell                                  0277        145,625         3.b.
4.  Loans and lease financing receivables:
    a. Loans and leases, net of unearned income RC-C).......   RCFD 2122 22,835,958                                 4.a.       
    b. LESS: Allowance for loan and lease losses............   RCFD 3123    418,851                                 4.b.      
    c. LESS: Allocated transfer risk reserve................   RCFD 3128          0                                 4.c.       
    d. Loans and leases, net of unearned
       income, allowance, and
       reserve (item 4.a minus 4.b and 4.c).................                            2125     22,417,107         4.d. 
5.  Assets held in trading accounts.........................                            3545      8,121,948         5.
6.  Premises and fixed assets (including capitalized                                                                    
     leases)................................................                            2145        707,971         6.   
7.  Other real estate owned (from Schedule RC-M)............                            2150          9,184         7.
8.  Investments in unconsolidated subsidiaries and            
    associated companies (from Schedule RC-M)...............                            2130         53,803         8.
9.  Customers' liability to this bank on acceptances                                    
    outstanding.............................................                            2155        626,690         9. 
10. Intangible assets (from Schedule RC-M)..................                            2143        310,246         10.    
11. Other assets (from Schedule RC-F).......................                            2160      1,658,123         11.    
12. Total assets (sum of items 1 through 11)................                            2170     49,956,726         12.     
</TABLE> 
__________________


(1)  Includes cash items in process of collection and unposted debits.
(2)  Includes time certificates of deposit not held for trading.
 

                                       5
<PAGE>
 
Legal Title of Bank:   The First National Bank of Chicago   09/30/96 ST-BK:
Address:               One First National Plaza, Ste 0460  17-1630 FFIEC 031  
City, State Zip:       Chicago, IL  60670                     Page RC-2 
FDIC Certificate No.:  0/3/6/1/8  
                       --------- 

                                 
SCHEDULE RC-CONTINUED

<TABLE> 
<CAPTION> 
                                                               DOLLAR AMOUNTS IN
                                                                   THOUSANDS                         BIL MIL THOU
                                                               ------------------                    ------------
<S>                                                            <C>                      <C>          <C>              <C> 
LIABILITIES
13.  Deposits:
     a. In domestic offices (sum of totals of 
        columns A and C from Schedule RC-E, part 1).............                        RCON 2200      22,369,341     13.a. 
        (1) Noninterest-bearing(1)..............................  RCON 6631  9,726,987                                13.a.(1) 
        (2) Interest-bearing....................................  RCON 6636 12,642,354                                13.a.(2)  
     b. In foreign offices, Edge and Agreement
        subsidiaries, and IBFs (from Schedule 
        RC-E, part II)..........................................                        RCFN 2200      10,026,286     13.b. 
        (1) Noninterest bearing.................................  RCFN 6631    336,746                                13.b.(1)  
        (2) Interest-bearing....................................  RCFN 6636  9,689,540                                13.b.(2)   
14.  Federal funds purchased and securities sold 
     under agreements to repurchase in domestic 
     offices of the bank and of its Edge and 
     Agreement subsidiaries, and in IBFs:                                
     a. Federal funds purchased.................................                        RCFD 0278         884,553     14.a.
     b. Securities sold under agreements to repurchase..........                        RCFD 0279         717,211     14.b.
15.  a. Demand notes issued to the U.S. Treasury................                        RCON 2840          14,120     15.a. 
     b. Trading Liabilities.....................................                        RCFD 3548       5,409,585     15b. 
16.  Other borrowed money:
     a. With original maturity of one year or less..............                        RCFD 2332       3,414,577     16.a. 
     b. With original maturity of more than one year............                        RCFD 2333          46,685     16b. 
17.  Mortgage indebtedness and obligations under 
     capitalized leases.........................................                        RCFD 2910         285,671     17.        
18.  Bank's liability on acceptance executed and 
     outstanding................................................                        RCFD 2920         626,690     18.
19.  Subordinated notes and debentures..........................                        RCFD 3200       1,250,000     19.
20.  Other liabilities (from Schedule RC-G).....................                        RCFD 2930       1,005,205     20. 
21.  Total liabilities (sum of items 13 through 20).............                        RCFD 2948      46,049,924     21.
22.  Limited-Life preferred stock and related surplus...........                        RCFD 3282               0     22. 
EQUITY CAPITAL
23.  Perpetual preferred stock and related surplus..............                        RCFD 3838               0     23. 
24.  Common stock...............................................                        RCFD 3230         200,858     24.
25.  Surplus (exclude all surplus related to preferred stock)                           RCFD 3839       2,925,894     25. 
26.  a. Undivided profits and capital reserves..................                        RCFD 3632         770,670     26.a. 
     b. Net unrealized holding gains (losses) on 
        available-for-sale securities...........................                        RCFD 8434          10,194     26.b. 
27.  Cumulative foreign currency translation adjustments........                        RCFD 3284            (814)    27.
28.  Total equity capital (sum of items 23 through 27)..........                        RCFD 3210       3,906,802     28.
29.  Total liabilities, limited-life preferred stock, and equity 
     capital (sum of items 21, 22, and 28)......................                        RCFD 3300      49,956,726     29.
</TABLE>

Memorandum
To be reported only with the March Report of Condition.
1.   Indicate in the box at the right the number of the statement below that
     best describes the most comprehensive level of auditing work performed for
     the bank by independent external                                   Number
                                                                      ---------
     auditors as of any date during 1995........... RCFD 6724........ N/A
                                                                      ---------

<TABLE> 
<S>                                                             <C> 
1 =  Independent audit of the bank conducted in accordance      4. =  Directors' examination of the bank performed by other 
     with generally accepted auditing standards by a                  external auditors (may be required by state
     certified public accounting firm which submits a report          chartering authority) 
     on the bank
2 =  Independent audit of the bank's parent holding company     5 =   Review of the bank's financial statements by external 
     conducted in accordance with generally accepted                  auditors
     auditing standards by a certified public accounting        6 =   Compilation of the bank's financial statements by external
     firm which submits a report on the consolidated holding          auditors  
     company (but not on the bank separately)                   7 =   Other audit procedures (excluding tax preparation work) 
3 =  Directors' examination of the bank conducted in            8 =   No external audit work
     accordance with generally accepted auditing
     standards by a certified public accounting firm (may 
     be required by state chartering authority)    
</TABLE> 
  
___________________
(1) Includes total demand deposits and noninterest-bearing time and savings
deposits.

                                       6

<PAGE>
 
                                                                    Exhibit 25.2

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM T-1
                                    --------

                            STATEMENT OF ELIGIBILITY
                     UNDER THE TRUST INDENTURE ACT OF 1939
                 OF A CORPORATION DESIGNATED TO ACT AS TRUSTEE

                CHECK IF AN APPLICATION TO DETERMINE ELIGIBILITY
                OF A TRUSTEE PURSUANT TO SECTION 305(B)(2) _____

                       _________________________________

                       THE FIRST NATIONAL BANK OF CHICAGO
              (EXACT NAME OF TRUSTEE AS SPECIFIED IN ITS CHARTER)

  A NATIONAL BANKING ASSOCIATION                           36-0899825
                                                        (I.R.S. EMPLOYER
                                                   IDENTIFICATION NUMBER)

ONE FIRST NATIONAL PLAZA, CHICAGO, ILLINOIS                    60670-0126
   (ADDRESS OF PRINCIPAL EXECUTIVE OFFICES)                    (ZIP CODE)

                       THE FIRST NATIONAL BANK OF CHICAGO
                      ONE FIRST NATIONAL PLAZA, SUITE 0286
                         CHICAGO, ILLINOIS 60670-0286
            ATTN:  LYNN A. GOLDSTEIN, LAW DEPARTMENT (312) 732-6919
           (NAME, ADDRESS AND TELEPHONE NUMBER OF AGENT FOR SERVICE)

                      ___________________________________

                            MCKESSON FINANCING TRUST
              (EXACT NAME OF OBLIGOR AS SPECIFIED IN ITS CHARTER)


         DELAWARE                                             52-6841546
 (STATE OR OTHER JURISDICTION OF                          (I.R.S. EMPLOYER
 INCORPORATION OR ORGANIZATION)                         IDENTIFICATION NUMBER)

     MCKESSON PLAZA
     ONE POST STREET
     SAN FRANCISCO, CALIFORNIA                                 94104
(ADDRESS OF PRINCIPAL EXECUTIVE OFFICES)                     (ZIP CODE)

                   5% TRUST CONVERTIBLE PREFERRED SECURITIES
                       (TITLE OF INDENTURE SECURITIES)

                                       1
<PAGE>
 
ITEM 1.   GENERAL INFORMATION.  FURNISH THE FOLLOWING
          --------------------                       
               INFORMATION AS TO THE TRUSTEE:

               (A) NAME AND ADDRESS OF EACH EXAMINING OR
               SUPERVISING AUTHORITY TO WHICH IT IS SUBJECT.

               Comptroller of Currency, Washington, D.C.,
               Federal Deposit Insurance Corporation,
               Washington, D.C., The Board of Governors of
               the Federal Reserve System, Washington D.C.

               (B) WHETHER IT IS AUTHORIZED TO EXERCISE
               CORPORATE TRUST POWERS.

               The trustee is authorized to exercise corporate
               trust powers.

ITEM 2.   AFFILIATIONS WITH THE OBLIGOR.  IF THE OBLIGOR
          ------------------------------                
               IS AN AFFILIATE OF THE TRUSTEE, DESCRIBE EACH
               SUCH AFFILIATION.

               No such affiliation exists with the trustee.

 
ITEM 16.       LIST OF EXHIBITS.   LIST BELOW ALL EXHIBITS FILED AS A
               -----------------                                     
               PART OF THIS STATEMENT OF ELIGIBILITY.

               1.  A copy of the articles of association of the
                   trustee now in effect.*

               2.  A copy of the certificates of authority of the
                   trustee to commence business.*

               3.  A copy of the authorization of the trustee to
                   exercise corporate trust powers.*

               4.  A copy of the existing by-laws of the trustee.*

               5.  Not Applicable.

               6.  The consent of the trustee required by
                   Section 321(b) of the Act.

                                       2
<PAGE>
 
          7. A copy of the latest report of condition of the
             trustee published pursuant to law or the
             requirements of its supervising or examining
             authority.

          8. Not Applicable.

          9. Not Applicable.


     Pursuant to the requirements of the Trust Indenture Act of 1939, as
     amended, the trustee, The First National Bank of Chicago, a national
     banking association organized and existing under the laws of the United
     States of America, has duly caused this Statement of Eligibility to be
     signed on its behalf by the undersigned, thereunto duly authorized, all in
     the City of Chicago and State of Illinois, on the 8th day of April, 1997.


                    THE FIRST NATIONAL BANK OF CHICAGO,
                    TRUSTEE

                    BY   /S/ RICHARD D. MANELLA

                         RICHARD D. MANELLA
                         VICE PRESIDENT
 


* EXHIBITS 1, 2, 3 AND 4 ARE HEREIN INCORPORATED BY REFERENCE TO EXHIBITS
BEARING IDENTICAL NUMBERS IN ITEM 16 OF THE FORM T-1 OF THE FIRST NATIONAL BANK
OF CHICAGO, FILED AS EXHIBIT 25.1 TO THE REGISTRATION STATEMENT ON FORM S-3 OF
SUNAMERICA INC. FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON OCTOBER 25,
1996 (REGISTRATION NO. 333-14201).

                                       3
<PAGE>
 
                                   EXHIBIT 6



                      THE CONSENT OF THE TRUSTEE REQUIRED
                          BY SECTION 321(b) OF THE ACT


                                    April 8, 1997
 


Securities and Exchange Commission
Washington, D.C.  20549

Gentlemen:

In connection with the qualification of the Amended and Restated Declaration of
Trust of McKesson Financing Trust, the undersigned, in accordance with Section
321(b) of the Trust Indenture Act of 1939, as amended, hereby consents that the
reports of examinations of the undersigned, made by Federal or State authorities
authorized to make such examinations, may be furnished by such authorities to
the Securities and Exchange Commission upon its request therefor.


                         Very truly yours,

                         THE FIRST NATIONAL BANK OF CHICAGO
 
                         BY:  /S/ RICHARD D. MANELLA
 
                              RICHARD D. MANELLA
                              VICE PRESIDENT

                                       4
<PAGE>
 
                                   EXHIBIT 7
 
Legal Title of Bank:    The First National Bank of    Call Date: 09/30/96 
Address:                Chicago One First National    ST-BK:  17-1630 FFIEC 031 
City, State  Zip:       Plaza, Ste 0460 Chicago,           Page RC-1 
FDIC Certificate No.:   IL  60670 0/3/6/1/8
                                  ---------

CONSOLIDATED REPORT OF CONDITION FOR INSURED COMMERCIAL
AND STATE-CHARTERED SAVINGS BANKS FOR SEPTEMBER 30, 1996

All schedules are to be reported in thousands of dollars.  Unless otherwise
indicated, report the amount
outstanding of the last business day of the quarter.

SCHEDULE RC--BALANCE SHEET

<TABLE>
<CAPTION>
                                                                         DOLLAR AMOUNTS IN               C400        LESS THAN -    
                                                                                                        ---------    ----------- 

                                                                            THOUSANDS        RCFD       BIL MIL THOU
                                                                         -----------------   ----       ------------
<S>                                                                      <C>                 <C>        <C>          <C>
ASSETS
1.  Cash and balances due from depository institutions (from Schedule
    RC-A):
    a. Noninterest-bearing balances and currency
    and coin(1)........................................................                          0081        4,041,784       1.a. 
    b. Interest-bearing balances(2)....................................                          0071        5,184,890       1.b. 
2.  Securities                                                                                                                    
    a. Held-to-maturity securities(from Schedule                                                                                  
    RC-B, column A)....................................................                          1754                0       2.a. 
    b. Available-for-sale securities (from                                                                                        
    Schedule RC-B, column D)...........................................                          1773        3,173,481       2.b. 
3.  Federal funds sold and securities purchased under agreements to                                                               
    resell in domestic offices of the bank and its Edge and Agreement                                                             
    subsidiaries, and in IBFs:                                                                                                    
    a. Federal Funds sold..............................................                          0276        3,505,874       3.a. 
    b. Securities purchased under agreements to resell.................                          0277          145,625       3.b. 
4.  Loans and lease financing receivables:
    a. Loans and leases, net of unearned income (from Schedule RC-C)
    b. LESS: Allowance for loan and lease losses.......................     RCFD 3123   418,851                              4.b.
    c. LESS: Allocated transfer risk reserve...........................     RCFD 3128         0                              4.c.
    d. Loans and leases, net of unearned income, allowance, and
    reserve (item 4.a minus 4.b and 4.c)...............................                          2125       22,417,107       4.d.  
5.  Assets held in trading accounts....................................                          3545        8,121,948       5.   
6.  Premises and fixed assets (including capitalized leases)...........                          2145          707,971       6.   
7.  Other real estate owned (from Schedule RC-M).......................                          2150            9,184       7.   
8.  Investments in unconsolidated subsidiaries and associated                                                                     
    companies (from Schedule RC-M).....................................                          2130           53,803       8.   
9.  Customers' liability to this bank on acceptances outstanding.......                          2155          626,690       9.   
10. Intangible assets (from Schedule RC-M).............................                          2143          310,246       10.  
11. Other assets (from Schedule RC-F)..................................                          2160        1,658,123       11.  
12. Total assets (sum of items 1 through 11)...........................                          2170       49,956,726       12.   
</TABLE>

__________________

(1)  Includes cash items in process of collection and unposted debits.
(2)  Includes time certificates of deposit not held for trading.
 

                                       5
<PAGE>
 
Legal Title of Bank:    The First National Bank of          Call Date: 09/30/96
Address:                Chicago One First National Plaza,   ST-BK: 17-1630 FFIE
City, State  Zip:       Ste 0460 Chicago, IL  60670         031 Page RC-2     
FDIC Certificate No.:   0/3/6/1/8                                             
                        ---------                                             
 
SCHEDULE RC-CONTINUED

<TABLE>
<CAPTION>
                                                                 DOLLAR AMOUNTS IN
                                                                     Thousands                       BIL MIL THOU
                                                                 ------------------                  ------------
<S>                                                             <C>                     <C>          <C>                <C>
LIABILITIES
13. Deposits:
    a. In domestic offices (sum of totals of
       columns A and C from Schedule RC-E, part 1)......                                RCON 2200      22,369,341       13.a.
       (1) Noninterest-bearing(1).......................        RCON 6631  9,726,987                                    13.a.(1)
       (2) Interest-bearing.............................        RCON 6636 12,642,354                                    13.a.(2)
    b. In foreign offices, Edge and Agreement
       subsidiaries, and IBFs (from Schedule
       RC-E, part II)...................................                                RCFN 2200      10,026,286       13.b.
       (1) Noninterest bearing..........................        RCFN 6631    336,746                                    13.b.(1)
       (2) Interest-bearing.............................        RCFN 6636  9,689,540                                    13.b.(2)
14. Federal funds purchased and securities
    sold under agreements to repurchase in
    domestic offices of the bank and of
    its Edge and Agreement subsidiaries,
    and in IBFs:
    a. Federal funds purchased..........................                                RCFD 0278         884,553       14.a.
    b. Securities sold under agreements
       to repurchase....................................                                RCFD 0279         717,211       14.b.
15. a. Demand notes issued to the U.S. Treasury.........                                RCON 2840          14,120       15.a.
    b. Trading Liabilities..............................                                RCFD 3548       5,409,585       15b.
16. Other borrowed money:
    a. With original maturity of one year or less.......                                RCFD 2332       3,414,577       16.a.
    b. With original maturity of more than
       one year.........................................                                RCFD 2333          46,685       16b.
17. Mortgage indebtedness and obligations under
    capitalized leases..................................                                RCFD 2910         285,671       17.
18. Bank's liability on acceptance executed and
    outstanding.........................................                                RCFD 2920         626,690       18.
19. Subordinated notes and debentures...................                                RCFD 3200       1,250,000       19.
20. Other liabilities (from Schedule RC-G)..............                                RCFD 2930       1,005,205       20.
21. Total liabilities (sum of items 13 through 20)......                                RCFD 2948      46,049,924       21.
22. Limited-Life preferred stock and related surplus....                                RCFD 3282           0           22.
EQUITY CAPITAL
23. Perpetual preferred stock and related surplus.......                                RCFD 3838           0           23.
24. Common stock........................................                                RCFD 3230         200,858       24.
25. Surplus (exclude all surplus related to preferred
    stock)..............................................                                RCFD 3839       2,925,894       25.
26. a. Undivided profits and capital reserves...........                                RCFD 3632         770,670       26.a.
    b. Net unrealized holding gains (losses) on
       available-for-sale securities....................                                RCFD 8434          10,194       26.b.
27. Cumulative foreign currency translation adjustments.                                RCFD 3284            (814)      27.
28. Total equity capital (sum of items 23 through 27)...                                RCFD 3210       3,906,802       28.
29. Total liabilities, limited-life  preferred stock,
    and equity capital (sum of items 21, 22, and 28)....                                RCFD 3300      49,956,726       29.
</TABLE>

Memorandum
To be reported only with the March Report of Condition.
1. Indicate in the box at the right the number of the statement below that best
   describes the  most
   comprehensive level of auditing work performed for the bank by independent
   external                                                Number
                                                         --------- 
auditors as of any date during 1995...........RCFD 6724..   N/A             M.1.
                                                         ---------

<TABLE> 
<S>                                                        <C>      
1 =  Independent audit of the bank conducted in             4. = Directors' examination of the bank performed              
     accordance                                                  by other                                                  
     with generally accepted auditing standards by               external auditors (may be required by state               
     a certified                                                 chartering                                                
     public accounting firm which submits a report               authority)                                                
     on the bank                                                                                                           
2 =  Independent audit of the bank's parent holding         5 =  Review of the bank's financial statements by              
     company                                                     external                                                  
     conducted in accordance with generally                      auditors                                                  
     accepted auditing                                                                                                     
     standards by a certified public accounting             6 =  Compilation of the bank's financial                       
     firm which                                                  statements by external                                    
     submits a report on the consolidated holding                auditors                                                  
     company                                                                                                               
     (but not on the bank separately)                       7 =  Other audit procedures (excluding tax                     
                                                                 preparation work)                                         
3 =  Directors' examination of the bank conducted in        8 =  No external audit work                                     
     accordance with generally accepted auditing
     standards by a certified public accounting firm 
     (may be required by state chartering authority)
</TABLE> 

___________________
(1) Includes total demand deposits and noninterest-bearing time and savings
deposits.

                                       6

<PAGE>
 
                                                                    Exhibit 25.3

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM T-1
                                    --------

                            STATEMENT OF ELIGIBILITY
                     UNDER THE TRUST INDENTURE ACT OF 1939
                 OF A CORPORATION DESIGNATED TO ACT AS TRUSTEE

                CHECK IF AN APPLICATION TO DETERMINE ELIGIBILITY
                OF A TRUSTEE PURSUANT TO SECTION 305(B)(2) _____

                       __________________________________ 

                       THE FIRST NATIONAL BANK OF CHICAGO
              (EXACT NAME OF TRUSTEE AS SPECIFIED IN ITS CHARTER)

  A NATIONAL BANKING ASSOCIATION                               36-0899825
                                                            (I.R.S. EMPLOYER
                                                         IDENTIFICATION NUMBER)

ONE FIRST NATIONAL PLAZA, CHICAGO, ILLINOIS              60670-0126
     (ADDRESS OF PRINCIPAL EXECUTIVE OFFICES)            (ZIP CODE)

                       THE FIRST NATIONAL BANK OF CHICAGO
                      ONE FIRST NATIONAL PLAZA, SUITE 0286
                         CHICAGO, ILLINOIS   60670-0286
            ATTN:  LYNN A. GOLDSTEIN, LAW DEPARTMENT (312) 732-6919
           (NAME, ADDRESS AND TELEPHONE NUMBER OF AGENT FOR SERVICE)

                       __________________________________ 

                            MCKESSON FINANCING TRUST
              (EXACT NAME OF OBLIGOR AS SPECIFIED IN ITS CHARTER)


     DELAWARE                                                  52-6841546
 (STATE OR OTHER JURISDICTION OF                             (I.R.S. EMPLOYER
 INCORPORATION OR ORGANIZATION)                           IDENTIFICATION NUMBER)

     MCKESSON PLAZA
     ONE POST STREET
     SAN FRANCISCO, CALIFORNIA                                      94104
(ADDRESS OF PRINCIPAL EXECUTIVE OFFICES)                          (ZIP CODE)


            GUARANTEE OF 5% TRUST CONVERTIBLE PREFERRED SECURITIES
                           MCKESSON FINANCING TRUST
                        (TITLE OF INDENTURE SECURITIES)

                                       1
<PAGE>
 
ITEM 1.   GENERAL INFORMATION.  FURNISH THE FOLLOWING
          --------------------                       
               INFORMATION AS TO THE TRUSTEE:

               (A) NAME AND ADDRESS OF EACH EXAMINING OR
               SUPERVISING AUTHORITY TO WHICH IT IS SUBJECT.

               Comptroller of Currency, Washington, D.C.,
               Federal Deposit Insurance Corporation,
               Washington, D.C., The Board of Governors of
               the Federal Reserve System, Washington D.C.

               (B) WHETHER IT IS AUTHORIZED TO EXERCISE
               CORPORATE TRUST POWERS.

               The trustee is authorized to exercise corporate
               trust powers.

ITEM 2.   AFFILIATIONS WITH THE OBLIGOR.  IF THE OBLIGOR
          ------------------------------                
               IS AN AFFILIATE OF THE TRUSTEE, DESCRIBE EACH
               SUCH AFFILIATION.

               No such affiliation exists with the trustee.

 
ITEM 16.       LIST OF EXHIBITS.   LIST BELOW ALL EXHIBITS FILED AS A
               -----------------                                     
               PART OF THIS STATEMENT OF ELIGIBILITY.

               1.  A copy of the articles of association of the
                   trustee now in effect.*

               2.  A copy of the certificates of authority of the
                   trustee to commence business.*

               3.  A copy of the authorization of the trustee to
                   exercise corporate trust powers.*

               4.  A copy of the existing by-laws of the trustee.*

               5.  Not Applicable.

               6.  The consent of the trustee required by
                   Section 321(b) of the Act.

                                       2
<PAGE>
 
          7.  A copy of the latest report of condition of the
              trustee published pursuant to law or the
              requirements of its supervising or examining
              authority.

          8.  Not Applicable.

          9.  Not Applicable.


     Pursuant to the requirements of the Trust Indenture Act of 1939, as
     amended, the trustee, The First National Bank of Chicago, a national
     banking association organized and existing under the laws of the United
     States of America, has duly caused this Statement of Eligibility to be
     signed on its behalf by the undersigned, thereunto duly authorized, all in
     the City of Chicago and State of Illinois, on the 8th day of April, 1997.


                    THE FIRST NATIONAL BANK OF CHICAGO,
                    TRUSTEE

                    BY   /S/ RICHARD D. MANELLA

                         RICHARD D. MANELLA
                         VICE PRESIDENT



* EXHIBITS 1, 2, 3 AND 4 ARE HEREIN INCORPORATED BY REFERENCE TO EXHIBITS
BEARING IDENTICAL NUMBERS IN ITEM 16 OF THE FORM T-1 OF THE FIRST NATIONAL BANK
OF CHICAGO, FILED AS EXHIBIT 25.1 TO THE REGISTRATION STATEMENT ON FORM S-3 OF
SUNAMERICA INC. FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON OCTOBER 25,
1996 (REGISTRATION NO. 333-14201).

                                       3
<PAGE>
 
                                   EXHIBIT 6



                      THE CONSENT OF THE TRUSTEE REQUIRED
                         BY SECTION 321(b) OF THE ACT


                                 April 8, 1997
 


Securities and Exchange Commission
Washington, D.C.  20549

Gentlemen:

In connection with the qualification of an indenture between McKesson
Corporation and The First National Bank of Chicago, the undersigned, in
accordance with Section 321(b) of the Trust Indenture Act of 1939, as amended,
hereby consents that the reports of examinations of the undersigned, made by
Federal or State authorities authorized to make such examinations, may be
furnished by such authorities to the Securities and Exchange Commission upon its
request therefor.


                         Very truly yours,

                         THE FIRST NATIONAL BANK OF CHICAGO
 
                         BY:  /S/ RICHARD D. MANELLA
 
                              RICHARD D. MANELLA
                              VICE PRESIDENT

                                       4
<PAGE>
 
                                   EXHIBIT 7


Legal Title of Bank:    The First National Bank of Chicago  Call Date: 09/30/96
Address:                One First National Plaza, Ste 0460  ST-BK: 17-1630 FFI
City, State  Zip:       Chicago, IL  60670                      EC 031
FDIC Certificate No.:   0/3/6/1/8                              Page RC-1  
                        ---------

CONSOLIDATED REPORT OF CONDITION FOR INSURED COMMERCIAL
AND STATE-CHARTERED SAVINGS BANKS FOR SEPTEMBER 30, 1996

All schedules are to be reported in thousands of dollars. Unless otherwise
indicated, report the amount outstanding of the last business day of the
quarter.

SCHEDULE RC--BALANCE SHEET

<TABLE>
<CAPTION>
                                                             DOLLAR AMOUNTS IN                            C400       LESS THAN-
                                                                                                       ------------  -----------
                                                                THOUSANDS                 RCFD         BIL MIL THOU
                                                             -----------------            ----         ------------
ASSETS
<S>                                                       <C>                             <C>          <C>               <C>
1.   Cash and balances due from depository institutions
     (from Schedule RC-A):
     a. Noninterest-bearing balances and currency
     and coin(1).......................................                                   0081         4,041,784         1.a.
     b. Interest-bearing balances(2)...................                                   0071         5,184,890         1.b.
2.   Securities
     a. Held-to-maturity securities(from Schedule
     RC-B, column A)...................................                                   1754                 0         2.a.
     b. Available-for-sale securities (from
     Schedule RC-B, column D)..........................                                   1773         3,173,481         2.b.
3.   Federal funds sold and securities purchased under
     agreements to resell in domestic offices of the
     bank and its Edge and Agreement subsidiaries,
     and in IBFs:
     a. Federal Funds sold.............................                                   0276         3,505,874         3.a.
     b. Securities purchased under agreements to
     resell............................................                                   0277           145,625         3.b.
4.   Loans and lease financing receivables:
     a. Loans and leases, net of unearned
     income (from Schedule RC-C).......................   RCFD 2122 22,835,958                                           4.a.
     b. LESS: Allowance for loan and lease
     losses............................................   RCFD 3123    418,851                                           4.b.
     c. LESS: Allocated transfer risk reserve..........   RCFD 3128          0                                           4.c.
     d. Loans and leases, net of unearned
     income, allowance, and reserve
     (item 4.a minus 4.b and 4.c)......................                                   2125        22,417,107         4.d.
5.   Assets held in trading accounts...................                                   3545         8,121,948         5.
6.   Premises and fixed assets (including
     capitalized leases)...............................                                   2145           707,971         6.
7.   Other real estate owned (from Schedule RC-M)......                                   2150             9,184         7.
8.   Investments in unconsolidated subsidiaries and
     associated companies (from Schedule RC-M).........                                   2130            53,803         8.
9.   Customers' liability to this bank on acceptances
     outstanding.......................................                                   2155           626,690         9.
10.  Intangible assets (from Schedule RC-M)............                                   2143           310,246        10.
11.  Other assets (from Schedule RC-F).................                                   2160         1,658,123        11.
12.  Total assets (sum of items 1 through 11)..........                                   2170        49,956,726        12.
</TABLE>
__________________


(1)  Includes cash items in process of collection and unposted debits.
(2)  Includes time certificates of deposit not held for trading.

                                       5
<PAGE>
 
<TABLE>
<S>                              <C>                                     <C>                                   <C>
Legal Title of Bank:             The First National Bank of Chicago      Call Date:  09/30/96 ST-BK:           17-1630 FFIEC 031
Address:                         One First National Plaza, Ste 0460                                            Page RC-2
City, State  Zip:                Chicago, IL  60670
FDIC Certificate No.:            0/3/6/1/8
                                 ---------

SCHEDULE RC-CONTINUED

                                               DOLLAR AMOUNTS IN
                                                   Thousands                                   BIL MIL THOU
                                               -----------------                               ------------
LIABILITIES
<S>  <C>                                       <C>                     <C>                     <C>               <C>
13.  Deposits:
     a. In domestic offices (sum of
        totals of columns A and C
        from Schedule RC-E, part 1)............                         RCON 2200                 22,369,341     13.a.
        (1) Noninterest-bearing(1)............. RCON 6631  9,726,987                                             13.a.(1)
        (2) Interest-bearing................... RCON 6636 12,642,354                                             13.a.(2)
     b. In foreign offices, Edge and
        Agreement subsidiaries, and
        IBFs (from Schedule RC-E, part II).....                         RCFN 2200                 10,026,286     13.b.
        (1) Noninterest bearing................ RCFN 6631    336,746                                             13.b.(1)
        (2) Interest-bearing................... RCFN 6636  9,689,540                                             13.b.(2)
14.  Federal funds purchased and
     securities sold under agreements
     to repurchase in domestic offices
     of the bank and of its Edge and
     Agreement subsidiaries, and
     in IBFs:
     a. Federal funds purchased................                         RCFD 0278                    884,553     14.a.
     b. Securities sold under..................                         RCFD 0279                    717,211     14.b.
     agreements to repurchase
15.  a. Demand notes issued to the
     U.S. Treasury.............................                         RCON 2840                     14,120     15.a.
     b. Trading Liabilities....................                         RCFD 3548                  5,409,585     15b.
16.  Other borrowed money:
     a. With original maturity of one
     year or less..............................                         RCFD 2332                  3,414,577     16.a.
     b. With original maturity of more
     than one year.............................                         RCFD 2333                     46,685     16b.
17.  Mortgage indebtedness and
     obligations under capitalized
     leases....................................                         RCFD 2910                    285,671     17.
18.  Bank's liability on acceptance
     executed and outstanding..................                         RCFD 2920                    626,690     18.
19.  Subordinated notes and debentures.........                         RCFD 3200                  1,250,000     19.
20.  Other liabilities (from Schedule
     RC-G).....................................                         RCFD 2930                  1,005,205     20.
21.  Total liabilities (sum of items
     13 through 20)............................                         RCFD 2948                 46,049,924     21.
22.  Limited-Life preferred stock and
     related surplus...........................                         RCFD 3282                          0     22.
EQUITY CAPITAL
23.  Perpetual preferred stock and
     related surplus...........................                         RCFD 3838                          0     23.
24.  Common stock..............................                         RCFD 3230                    200,858     24.
25.  Surplus (exclude all surplus
     related to preferred stock)...............                         RCFD 3839                  2,925,894     25.
26.  a. Undivided profits and capital reserves.                         RCFD 3632                    770,670     26.a.
     b. Net unrealized holding gains
     (losses) on available-for-sale
     securities................................                         RCFD 8434                     10,194     26.b.
27.  Cumulative foreign currency
     translation adjustments...................                         RCFD 3284                       (814)    27.
28.  Total equity capital (sum of
     items 23 through 27)......................                         RCFD 3210                  3,906,802     28.
29.  Total liabilities, limited-life
     preferred stock, and equity
     capital (sum of items 21, 22, and
     28).......................................                         RCFD 3300                 49,956,726     29.
</TABLE>

<TABLE> 
<S>                                                                                         <C> 
Memorandum
To be reported only with the March Report of Condition.
1. Indicate in the box at the right the number of the statement below that best
   describes the  most
   comprehensive level of auditing work performed for the bank by independent
   external                                                                                    Number
                                                                                             ----------------
   auditors as of any date during 1995  . . . . . . . . . . . . . . . . ....RCFD 6724......  N/A                 M.1.
                                                                                             ----------------
</TABLE> 

<TABLE> 
<S>                                                                 <C> 
1 =   Independent audit of the bank conducted in                    4. =  Directors' examination of the bank performed
      accordance with generally accepted auditing standards by            by other external auditors (may be required by state
      a certified public accounting firm which submits a report           chartering authority)
      on the bank                                                   5 =   Review of the bank's financial statements by 
2 =   Independent audit of the bank's parent holding                      external auditors                             
      company conducted in accordance with generally                6 =   Compilation of the bank's financial 
      accepted auditing standards by a certified public                   statements by external auditors      
      accounting  firm which submits a report on the                7 =   Other audit procedures (excluding tax   
      consolidated holding  company auditors                              preparation work)                       
      (but not on the bank separately)                              8 =   No external audit work                   
3 =   Directors' examination of the bank conducted in               
      accordance with generally accepted auditing
      standards by a certified public accounting
      firm (may be required by state chartering authority)          
</TABLE> 
_______________________
(1) Includes total demand deposits and noninterest-bearing time and savings
    deposits.

                                       6


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