EXHIBIT 23.1 CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS We hereby consent to the incorporation by reference of our report dated December 26, 2001 relating to the financial statements of Lafon Group in the Registration Statements on Forms S-3 (Nos. 33-74320, 333-20321, 333-75281, 333-88985, 333-94219, 333-59410, 333-62234 and 333-82788) and Forms S-8 (Nos. 33-43716, 33-71920, 333-02888, 333-69591, 333-89909, 333-87421, 333-52640, 333-43104) of Cephalon, Inc. Paris, France April 16, 2002 Befec-Price Waterhouse Member of PricewaterhouseCoopers /s/ LILIANE TELLIER - -------------------------------- Liliane Tellier Partner