EXHIBIT 23.1 CONSENT OF INDEPENDENT ACCOUNTANTS We consent to the incorporation by reference in the Registration Statements of Sepracor Inc. on Form S-8 (File Nos. 33-43460, 33-44808, 33-48428, 333-05217, 333-05219, 333-94774, 333-48719, 333-05221, 333-58557, 333-58559, 333-58563, 33-48429, 33-63710 and 33-79724) and Form S-3 (File Nos. 333-460 and 333-51879) of our reports dated February 19, 1999, except as to the information in Note W for which the date is February 25, 1999, on our audits of the consolidated financial statements and financial statement schedule of Sepracor Inc. as of December 31, 1998 and 1997 and for each of the three years in the period ended December 31, 1998, which reports are incorporated by reference in this Annual Report on Form 10-K. /s/ PricewaterhouseCoopers LLP Boston, Massachusetts March 29, 1999