A 76-year-old Caucasian woman developed fulminant hepatic necrosis 6 days after an uneventful operation under isoflurane anaesthesia. Laboratory findings included elevated bilirubin, grossly elevated transaminases and prolonged prothrombin time. Radiological investigation showed no evidence of extra-hepatic disease. Serological studies were negative for acute viral hepatitis and autoimmune disease. The patient may have been previously sensitized by exposure to isoflurane 3 years previously but antibodies to tri-fluoro acetate, present in 70% of cases of halothane hepatitis, were not detected in pre-operative or postoperative samples of blood. On the seventh postoperative day the patient died and postmortem examination demonstrated centrilobular necrosis of the liver, with a histological pattern similar to changes associated with halothane hepatitis.