<PAGE>
EXHIBIT 5.1
[Letterhead of Winston & Strawn]
October 13, 2000
MediChem Life Sciences, Inc.
12305 South New Avenue
Lemont, Illinois 60439
Re: Registration Statement on Form S-1 (File No. 333-39548)
------------------------------------------------------
Ladies and Gentlemen:
This opinion is being delivered by us, as counsel to MediChem Life
Sciences, Inc., a Delaware corporation (the "Company"), in connection with the
Registration Statement on Form S-1, File No. 333-39548, as amended (the
"Registration Statement"), of the Company filed with the Securities and Exchange
Commission (the "Commission") under the Securities Act of 1933, as amended (the
"Securities Act"). The Registration Statement relates to the offering by the
Company of shares of the Company's common stock, par value $0.01 per share (the
"Shares").
In rendering the opinion set forth below, we examined and relied upon
such certificates, corporate and public records, agreements, instruments and
other documents we considered appropriate as a basis for the opinion.
Based upon and subject to the foregoing, we are of the opinion that
when the Registration Statement has become effective under the Securities Act
and the Shares are issued and sold as contemplated by the Registration
Statement, the Shares will be validly issued, fully paid and nonassessable.
The foregoing opinion is limited to the federal laws of the United
States and the General Corporation Law of the State of Delaware, and we are
expressing no opinion as to the effect of the laws of any other jurisdiction.
While we are not licensed to practice law in the State of Delaware, we have
reviewed applicable provisions of the Delaware General Corporation Law as we
have deemed appropriate in connection with the opinion.
We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference to us under the caption "Legal
Matters" in the Registration Statement. In giving such 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.
Very truly yours,
WINSTON & STRAWN