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                                                                    GENZYME CORPORATION
  [LOGO]                                                            ONE KENDALL SQUARE
                                                                    CAMBRIDGE, MA 02139
                                                                    617-252-7500



                                                               November 29, 2000

Dear Stockholder:

We previously sent you proxy materials in connection with the upcoming Special
Meeting of Genzyme Corporation stockholders scheduled for December 15, 2000.

We strongly believe that Genzyme Biosurgery--combining the products, product
development capabilities and marketing horsepower of Genzyme Surgical Products
and Genzyme Tissue Repair and Biomatrix, Inc.--will be a formidable combination
with many strengths, such as:

    - Innovative products, including a combined portfolio of 24 approved,
      commercially available products, many of them early in their product
      growth cycle, plus a broad pipeline of additional products in clinical
      development;

    - A premier R&D organization, broad marketing and sales experience, and an
      outstanding manufacturing and regulatory infrastructure; and

    - The financial depth to establish and maintain a leadership position in the
      emerging biosurgery field.

Your Board of Directors and management believe the collective strength of these
three organizations working together as Genzyme Biosurgery will create
opportunities for increasing shareholder value that exceed the opportunities for
each of these businesses separately.

YOUR BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS THAT YOU VOTE "FOR" EACH OF THE
PROPOSALS RELATING TO THE FORMATION OF GENZYME BIOSURGERY.

YOUR VOTE IS IMPORTANT, no matter how many or few shares you may own. If you
have not yet voted, please vote TODAY by telephone, by Internet, or by signing
and returning the enclosed voting form in the postage-paid envelope provided.
IMPORTANT: If you own more than one issue of Genzyme shares, you will receive
separate voting forms for each issue. Please remember to vote ALL your Genzyme
shares. Remember: Your failure to vote any shares is the equivalent of voting no
with those shares.

If you have any questions, or need any assistance in voting your shares, please
call our proxy solicitor, Innisfree M&A Incorporated, toll-free, at
1-800-750-9496.

Thank you for your vote and for your support.

Sincerely,

[/S/ HENRI A. TERMEER]

Henri A. Termeer
CHAIRMAN OF THE BOARD,
PRESIDENT AND CHIEF EXECUTIVE OFFICER

THIS LETTER CONTAINS FORWARD-LOOKING STATEMENTS, INCLUDING STATEMENTS ABOUT THE
FUTURE GROWTH OF THE PRODUCTS THAT WE WOULD ALLOCATE TO GENZYME BIOSURGERY, THE
FUTURE FINANCIAL POSITION OF GENZYME BIOSURGERY, AND THE FUTURE DEVELOPMENT OF
THE BIOSURGERY FIELD. ACTUAL RESULTS COULD DIFFER MATERIALLY. FACTORS THAT WILL
IMPACT ACTUAL RESULTS INCLUDE OUR ABILITY TO PENETRATE MARKETS, WHICH WILL
REQUIRE THAT WE CONVINCE MEDICAL PROFESSIONALS TO ADOPT GENZYME BIOSURGERY'S
NOVEL PRODUCTS; COMPETITION FROM COMPANIES THAT MARKET RIVAL THERAPIES;
LEGISLATIVE AND REGULATORY CHANGES THAT IMPACT OUR PROFITABILITY; OUR ABILITY TO
SATISFY THE SUBSTANTIAL REGULATORY REQUIREMENTS APPLICABLE TO HUMAN HEALTH CARE
PRODUCTS; AND THE OUTCOME OF CLINICAL TRIALS TO TEST OUR PRODUCT CANDIDATES.
MORE DETAILED DESCRIPTIONS OF THESE AND OTHER FACTORS THAT COULD ADVERSELY
IMPACT FUTURE RESULTS ARE INCLUDED IN THE JOINT PROXY STATEMENT/PROSPECTUS THAT
WE PREVIOUSLY MAILED TO YOU.

THIS LETTER IS NOT A SUBSTITUTE FOR THE JOINT PROXY STATEMENT/PROSPECTUS. IF YOU
DID NOT RETAIN THE COPY THAT WE PREVIOUSLY SENT YOU, YOU CAN OBTAIN A COPY FREE
OF CHARGE, AS WELL AS COPIES OF THE DOCUMENTS INCORPORATED BY REFERENCE INTO THE
JOINT PROXY STATEMENT/PROSPECTUS, AT THE SEC'S WEB SITE (WWW.SEC.GOV) OR FROM
GENZYME OR BIOMATRIX. WE URGE YOU TO READ THE JOINT PROXY STATEMENT/PROSPECTUS
BEFORE VOTING BECAUSE IT CONTAINS IMPORTANT INFORMATION.