We report the case of a patient who developed acute hepatitis with extensive hepatocellular necrosis, 7 months after the onset of administration of clotiazepam, a thienodiazepine derivative. Clotiazepam withdrawal was followed by prompt recovery. The administration of several benzodiazepines, chemically related to clotiazepam, did not interfere with recovery and did not induce any relapse of hepatitis. This observation shows that clotiazepam can induce acute hepatitis and suggests that there is no cross hepatotoxicity between clotiazepam and several benzodiazepines.