1 Exhibit 23.1 Consent of Independent Auditors We consent to the incorporation by reference in the Registration Statement (Form S-8 Nos. 333-00864, 333-06779, 333-08535) of GelTex Pharmaceuticals, Inc. of our report dated February 21, 1997 with respect to the financial statements of GelTex Pharmaceuticals, Inc. included in the Annual Report (Form 10-K) for the year ended December 31, 1996. ERNST & YOUNG LLP Boston, Massachusetts March 25, 1997