A 46-year-old male patient developed jaundice after 23 days' treatment of propylthiouracil (PTU) for Graves' disease. Serum alkaline phosphatase was elevated markedly with moderate increase in serum aminotransferase, and the peak level of total bilirubin was 7.3 mg/dL. After withdrawal of PTU, serum aminotransferase and bilirubin began to decrease simultaneously, and completely normalized. One week after the discharge from hospital, he received radioiodine treatment for Graves' disease, but he showed aggravation of hyperthyroidism and ophthalmopathy. So we prescribed methimazole inevitably 16 days' after the radiodiodine treatment. He developed jaundice again after 69 days' treatment of methimazole, but the pattern of hepatotoxicity was slightly different from that of the previous PTU-induced hepatotoxicity. Serum aminotransferase increased slightly and quickly normalized after discontinuance of methimazole, but serum total bilirubin increased continuously and reached to 24.6 mg/dL. Eosinophilia was prominent and the result of liver biopsy was compatible with cholestatic jaundice. The patient was treated with prednisolone and recovered from jaundice rapidly. (Korean J Hepatol 1999;5:136－141)
