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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 Amendment
No. 1 to the Registration Statement (Form S-3, No. 333-93481) 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 (Form 10-K) for
the year ended December 31, 1998 filed with the Securities and Exchange
Commission.


                                             /s/ ERNST & YOUNG LLP

Walnut Creek, California
January 27, 2000