A 71-year-old woman was being treated with Sho-saiko-to for chronic hepatitis. On the 14th day, she complained of dyspnea; chest X-ray films and CT scans revealed ground-glass shadows in both lung fields. Under a suspected diagnosis of drug-induced pneumonia, Sho-saiko-to was discontinued and the patient was started on prednisolone. After several days, her laboratory data and chest X-ray findings were markedly improved. Cell analysis of bronchoalveolar lavage fluid disclosed an increase in the lymphocyte fraction and a depressed CD4/CD8 count. Lymphocyte stimulation tests of Sho-saiko-to and its ingredients, Ohgon and Hange, were positive in the case of peripheral lymphocytes, but not bronchoalveolar lavage lymphocytes. These findings yielded a diagnosis of drug-induced pneumonia caused by Sho-saiko-to. A histologic examination of needle biopsy specimens from the liver revealed severe lymphocytic infiltration into the tissues of Glisson's capsule and liver parenchyma, and mild infiltration by plasma cells into tissues surrounding Glisson's capsule. To our knowledge, this is the first case of autoimmune hepatitis with Sho-saiko-to-induced pneumonia to be reported.