Exhibit 99.1

     STEMCELLS, INC. PLACES ALL REMAINING MODEX THERAPEUTICS FOUNDER'S STOCK
                        SHARES SOLD IN PRIVATE PLACEMENT

Palo Alto, Calif. -- April 30, 2001 --StemCells, Inc. (Nasdaq: STEM) announced
today that it has sold all of its remaining founder's shares in the Swiss Modex
Therapeutics, Ltd. (SWX New Market: MDXN) in a private placement. StemCells,
Inc. sold 103,577 shares at a net price of 87.00 CHF (Swiss francs) per share,
or a total sum of approximately US $5,200,000.

StemCells, Inc. was one of the original founders of Modex Therapeutics and the
original developer of its encapsulated cell technology (ECT). Rights to the ECT
technology were sold to the French company Neurotech, SA in exchange for an
immediate payment plus future royalty payments. In exchange for Modex'
assistance in placing the shares, which have been acquired by European
institutional investors, plus a payment of US $300,000 from Modex Therapeutics
to StemCells, Inc., the rights to these future royalty payments have been
transferred to Modex Therapeutics. StemCells retains its licenses to use the ECT
in its current programs and for the development of future vaccine technologies.

       "The liquidation of the Modex shares at this time by StemCells allows our
company to build value in our technology in a non-dilutive way. This is
particularly important in very difficult U.S. equity markets," said Martin
McGlynn, President and CEO of StemCells, Inc. "After StemCells Inc. restructured
and focused on its core business of stem cell technology, it became advantageous
to the Company to divest itself of its ECT assets."

ABOUT STEMCELLS, INC.

StemCells, Inc., is a biotechnology company focused on the discovery,
development and commercialization of stem cell-based therapies to treat diseases
of the central nervous system, liver, and pancreas. The Company's stem cell
programs seek to repair or repopulate tissue that has been damaged or lost as a
result of disease or injury.

Statements in this press release other than statements of historical facts
constitute forward looking statements regarding, among other things, the future
business operations of StemCells, Inc., or of StemCells California, Inc., its
wholly-owned subsidiary (collectively, "the Company"). The Company's actual
results may vary materially from those contemplated in the forward looking
statements due to risks and uncertainties to which the Company is subject,
including uncertainties regarding the Company's ability to obtain the capital
resources needed to conduct the research, preclinical development and clinical
trials required to develop products and obtain regulatory approvals; the fact
that the Company's stem cell technology is at the preclinical stage and has not
yet led to the development of any proposed product; the risk that any products
that may be generated in the future in the Company's stem cell programs may not
prove clinically safe or effective or may cause tumors or other adverse side
effects; the uncertainty whether the Company will achieve revenues from product
sales or become profitable; and other risks and uncertainties described in
Exhibit 99 to the Company's Annual Report on Form 10-K entitled "Cautionary
Factors Relevant to Forward Looking Statements."