Eight patients developed elevations of hepatic enzymes while receiving oxacillin intravenously. In all instances the patients were asymptomatic and anicteric. Peripheral eosinophilia was present in five of eight patients. In each patient change of therapy to a different pencillinase-resistant penicillin or to penicillin G was associated with a rapid decrease in liver function abnormalities and evenutal return of the enzymatic values to normal. Change of medication to an alternative penicillinase-resistant penicillin or to penicillin G is suggested as a safe procedure for completion of antistaphylococcal therapy in patient who develop oxacillin-related hepatotoxicity.