EXHIBIT 23.1

               CONSENT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS

      We consent to the incorporation by reference in the Registration
Statement (Form S-8 No. 333-66700) pertaining to the 2001 Equity Incentive
Plan, in the Registration Statements (Form S-8 No. 333-49524 and 333-29335)
pertaining to the 1998 Incentive Stock Plan, 1992 Equity Incentive Plan, 1992
Employee Stock Purchase Plan and 1992 Stock Option Plan for Non-Employee
Directors, in the Registration Statement (Form S-8 No. 333-10773) pertaining
to the 1992 Equity Incentive Plan, in the Registration Statement (Form S-8
No. 333-37313) pertaining to the 1996 StemCells, Inc. Stock Option Plan and
the 1997 CytoTherapeutics, Inc. StemCells Research Stock Option Plan, in the
Registration Statements (Form S-3 No. 333-75806, No. 333-66692, No. 333-61726
and No. 333-83992) of Stemcells, Inc. and in the Registration Statements
(Form S-3 No. 333-68900 and No. 333-91228) of CytoTherapeutics, Inc. and in
the related Prospectuses of our report dated March 4, 2003, with respect to
the consolidated financial statements of StemCells, Inc. included in the
Annual Report (Form 10-K) for the year ended December 31, 2002.

                                                           /s/ Ernst & Young LLP

Palo Alto, California
March 28, 2003