A 76-year-old woman admitted to our hospital for jaundice had been treated for diabetes mellitus with insulin for 9 years and voglibose had been added for the 39 months preceding admission. Elevated serum bilirubin and transaminase concentration began to normalize with initiation of corticosteroid treatment 1 week after discontinuation of voglibose. In the in vitro testing of the patient's peripheral blood, lymphocytes showed stimulation by voglibose. In dramatic contrast to an initial liver biopsy specimen that demonstrated cholestasis with submassive and zonal necrosis, the follow-up specimen was normal 1 year later. We believe that patients treated with voglibose should be monitored long-term with monthly determinations of transaminases and bilirubin in serum.