From 1974 through 1982, fulminant hepatitis was diagnosed in 34 patients at our institution. Of these patients, only two survived (survival rate, 6%). This syndrome was caused by viruses (B and non-B hepatitis and herpes simplex) in 23 patients, hepatotoxic drug in 6, Wilson's disease (hepatolenticular degeneration) in 3, and industrial poisons in 2. Most of the patients died within 10 days after the onset of encephalopathy. The poor prognosis in our group of patients was probably related to the preponderance of older patients and cases caused by non-B hepatitis virus. In our patients, the clinical course was complicated by renal failure, ascites, bleeding, sepsis, pancreatitis, and seizures. The major cause of death was hepatic failure.