<PAGE>
EXHIBIT 23.1
CONSENT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS
We consent to the reference to our firm under the caption "Experts" and to the
use of our report dated May 22, 2000 (except for Note 16, as to which the date
is July 10, 2000 and Note 17, as to which the date is June 30, 2000) in
Amendment No. 2 to the Registration Statement (Form S-1 No. 333-34896) and
related Prospectus of Pharsight Corporation for the registration of 4,312,500
shares of its common stock.
/s/ ERNST & YOUNG, LLP
San Jose, California
July 11, 2000
