EXHIBIT 23.1 CONSENT OF INDEPENDENT ACCOUNTANTS We hereby consent to the incorporation by reference in this Registration Statement on Form S-8 of Interneuron Pharmaceuticals, Inc. of our report dated December 1, 1999, except as to Note N which is as of December 27, 1999, relating to the consolidated financial statements which appear in Interneuron Pharmaceuticals, Inc.'s Annual Report on Form 10-K for the year ended September 30, 1999. We also consent to the reference to us under the heading "Experts" in such registration statement. /s/ PricewaterhouseCoopers LLP Boston, Massachusetts February 8, 2000