We present a fatal case of acute submassive hepatic necrosis occurring in a 42-yr-old black woman treated for hyperthyroidism with propylthiouracil for 1 yr. Alcohol and drug abuse were ruled out and all serological tests for hepatitis A and B, cytomegalovirus, and Epstein-Barr virus infection were negative. At autopsy the liver was shrunken and presented a yellow granular appearance. Microscopy disclosed submassive necrosis with bile stasis and severe chronic inflammation, as well as mild bile duct proliferation. Although non-A, non-B hepatitis cannot be ruled out (there was no transfusion of blood or its products), this is considered to be the third fatal case and ninth instance of propylthiouracil-induced hepatic necrosis.