Five case histories are presented of patients developing cholestatic hepatitis associated with the intake of the antibiotic combination agent amoxicillin and clavulanic acid (Augmentin). In two of these cases, signs of hepatic injury recurred after readministration of this combination but not after the intake of amoxicillin alone. In none of the patients was another cause for cholestatic hepatitis found and extrahepatic causes were excluded by ultrasonography, CT scanning, or ERCP. Most viral causes of hepatic injury were excluded in these patients. With the exception of one patient, who developed a transient rash, no immunoallergic signs were present. Biopsy in two patients showed extensive cholestasis without significant necrosis. Clavulanic acid seems to be responsible for this adverse effect.