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                                                                    EXHIBIT 23.1


               CONSENT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS

We consent to the incorporation by reference in this Registration Statement on
Form S-8 pertaining to the 2000 Equity Compensation Plan of Arena
Pharmaceuticals, Inc. of our report dated May 29, 2000, except for the last
paragraph of Note 10, as to which the date is July 25, 2000, with respect to the
financial statements of Arena Pharmaceuticals, Inc. included in the Registration
Statement (Form S-1 No. 333-35944) of Arena Pharmaceuticals, Inc. as filed with
the Securities and Exchange Commission.



                                       /s/ ERNST & YOUNG, LLP


San Diego, California
September 7, 2000



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