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                                                                    EXHIBIT 23.1

               CONSENT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS

We consent to the reference to our firm under the caption "Experts" in the
Registration Statement on Form S-3 and related Prospectus of Cerus Corporation
for the registration of 1,000,000 shares of its Common Stock and to the
incorporation by reference therein of our report dated January 22, 1999, except
for Note 2 as to which the date is January 30, 1999, and Note 5, as to which the
date is March 3, 1999, with respect to the financial statements of Cerus
Corporation included in its Annual Report on Form 10-K for the year ended
December 31, 1998 filed with the Securities and Exchange Commission.


                                             /s/ ERNST & YOUNG LLP

Walnut Creek, California
December 21, 1999