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                                                                    EXHIBIT 99.1

Contact:

    Cerus Corporation                     Noonan/Russo Communications, Inc.
    (925) 603-9071                        (415) 677-4455
    Stephen Isaacs, President and CEO     Amy Giller, Investors
    Greg W. Schafer, CFO                  Amy Flood, Media

                CERUS CORPORATION ADOPTS STOCKHOLDER RIGHTS PLAN

Concord, Calif., November 3, 1999 -- Cerus Corporation (Nasdaq: CERS) announced
that its Board of Directors approved the adoption of a Stockholder Rights Plan
under which all stockholders of record as of November 23, 1999 will receive
rights to purchase shares of a new series of Preferred Stock.

The Rights Plan is designed to enable all Cerus stockholders to realize the full
value of their investment and to provide for fair and equal treatment for all
stockholders in the event that an unsolicited attempt is made to acquire Cerus.
The adoption of the Rights Plan is intended as a means to guard against abusive
takeover tactics and is not in response to any particular proposal.

The rights will be distributed as a non-taxable dividend and will expire ten
years from the record date. The rights will be exercisable only if a person or
group acquires 15% or more of the Cerus Corporation Common Stock or announces a
tender offer for fifteen percent or more of the Common Stock. If a person or
group acquires 15% or more of the company's Common Stock, all rightsholders
except the buyer will be entitled to acquire the company's Common Stock at a
discount. Baxter Healthcare Corporation will be exempt from the Rights Plan,
unless Baxter acquires beneficial ownership of 20.1% or more of the Company's
Common Stock, excluding for this purpose shares of the company's Common Stock
issuable upon conversion of Preferred Stock of Cerus now held by Baxter. The
effect will be to discourage acquisitions of more than 15% of the Common Stock
of Cerus without negotiations with the Board.


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The rights will trade with the company's Common Stock, unless and until they are
separated upon the occurrence of certain future events. The company's Board of
Directors may terminate the Rights Plan at any time or redeem the rights prior
to the time a person acquires more than 15% of the company's Common Stock.
Additional details regarding the Rights Plan will be outlined in a summary to be
mailed to all stockholders following the record date.

Cerus Corporation is a leading developer of systems to improve the safety of
transfusion blood products through inactivation of viruses, bacteria and other
pathogens. In addition to systems to treat platelets, plasma and red blood cells
intended for transfusion, Cerus is developing a system to treat source plasma
used for fractionation into various plasma products. The company's platform
technologies, which prevent viral, bacterial and other cellular replication,
have potential applications in the health care field beyond pathogen
inactivation in blood components. Cerus has collaboration agreements with Baxter
Healthcare and the Consortium for Plasma Science.

Statements in this news release are forward-looking statements that involve
risks and uncertainties. Actual results could differ materially from the above
forward-looking statements as a result of certain factors, including factors
discussed in the company's 1998 Annual Report on Form 10-K.

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