Exhibit 99

     CUBIST PHARMACEUTICALS COMPLETES ACQUISITION OF TERRAGEN DISCOVERY INC.
   Technology Significantly Expands Company's Capabilities in Natural Product
                                 Drug Discovery

            CAMBRIDGE, Mass., Oct. 25 -- Cubist Pharmaceuticals, Inc. (Nasdaq:
CBST) today announced that it has completed the acquisition of TerraGen
Discovery Inc., a privately held natural products discovery company with
operations in Vancouver, Canada and Slough, England. With the acquisition,
Cubist has enhanced both its antimicrobial drug discovery platform and product
development engine and obtained proprietary technologies and expertise in the
area of small molecule drug discovery from natural products.

         (Photo: http://www.newscom.com/cgi-bin/prnh/20000717/CUBELOGO)

            In addition to a pool of talented employees, Cubist has added
innovative and unique technologies that include:

            --    NatChem(TM), which provides access to over 50,000 extracts
                  derived from a unique collection of previously accessible
                  microorganisms (approximately 1% of existing microbes),

            --    NatGen(TM), which provides access to recombinant microbial
                  strains generated by cloning DNA from previously uncultivable
                  microorganisms (approximately 99% of existing microbes),

            --    Directed Biosynthesis, which enables the production of natural
                  product analogs via the alteration of genetic pathways in
                  surrogate host strains, and

            --    Macrodroplet Screening, which enables the rapid identification
                  of extracts from recombinant organisms through use of a
                  proprietary, high-throughput microfermentation screening
                  technology.

            Under the terms of the acquisition, Cubist has acquired 100% of the
shares of TerraGen in a stock-for-stock merger that is being accounted for under
a pooling-of-interest treatment. Cubist has issued approximately $29 million
worth of stock, or approximately 608,000 shares, which is 2.2% of its
post-transaction, outstanding primary share count. As of June 30, 2000, Cubist
had 27.1 million shares outstanding.

            Cubist Pharmaceuticals is focused on becoming a global leader in the
research, development and commercialization of novel antimicrobial drugs to
combat serious and life-threatening bacterial and fungal infections. Cubist is
evaluating the safety and efficacy of Cidecin(TM) (daptomycin for injection) in
the EDGE(TM) (Evaluation of Daptomycin in Gram-positive Entities) clinical trial
program and is engaged in multiple, strategic partnerships, including Novartis
Pharma AG and Merck & Co. for the discovery and development of novel
antiinfectives.

            Cubist Safeharbor Statement

            Statements contained herein that are not historical fact may be
forward-looking statements within the meaning of Section 27A of the Securities
Act of 1933 and Section 21E of the Securities Exchange Act of 1934, that are
subject to a variety of risks and uncertainties. There are a number of important
factors that could cause actual results to differ materially from those
projected or suggested in any forward-looking statements made by the Company.
These factors include, but are not limited to: (i) the Company's ability to
successfully complete product


                                      -2-


research and development, including pre-clinical and clinical studies and
commercialization; (ii) the Company's ability to obtain required governmental
approvals; (iii) the Company's ability to attract and/or maintain manufacturing,
sales, distribution and marketing partners; and (iv) the Company's ability to
develop and commercialize its products before its competitors. Additional
factors that would cause actual results to differ materially from those
projected or suggested in any forward-looking statements are contained in the
Company's filings with the Securities and Exchange Commission, including those
factors discussed under the caption "Risk Factors" in the Company's Annual
Report on Form 10-K/A (file No. 000-21379) filed on April 3, 2000.

SOURCE  Cubist Pharmaceuticals, Inc.

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Company News On-Call:  http://www.prnewswire.com/comp/.html119304 or fax,
800-758-5804, ext. 119304

CONTACT: Jennifer LaVin, Senior Director, Corporate Communications of Cubist
Pharmaceuticals, Inc., 617-576-4258, jlavin@cubist.com, or Renee Connolly -
media of Noonan/Russo Communications, 212-696-4455 ext. 227,
renee@noonanrusso.com


CAPTION: CUBELOGO    CUBIST PHARMACEUTICALS LOGO    Cubist Pharmeceuticals
Logo. (PRNewsFoto)[AG]    CAMBRIDGE, MA USA 07/17/2000