A case of PIE syndrome induced by Saiboku-To (TJ96) is reported. A 56-year-old woman had been treated for intractable bronchial asthma since the age of 42 years. She had a history of PIE syndrome induced by disodium cromoglycate 4 years previously (Jpn. J. Thoracic Disease, 27.1.1989). To reduce the dose of prednisolone for her asthma, administration of TJ96 was started in Dec. 1989. After 5 months of TJ96 treatment, she developed dry cough, fever, and chest pain. Physical findings and laboratory examinations revealed pulmonary infiltrations in the right lung field and severe eosinophilia. Because of suspected drug-induced PIE, TJ96 was stopped and 30 mg/day prednisolone was administered. Her symptoms and laboratory abnormalities subsequently resolved. To confirm the diagnosis of drug-induced PIE syndrome, drug-induced lymphocyte stimulation tests with TJ96 and other drugs were performed. TJ96 significantly induced lymphocyte blastogenesis with a stimulation index of 6.1. Moreover, the supernatant of the incubation mixture of TJ96 and peripheral lymphocytes from the patient showed marked eosinophil chemotactic activity. To our knowledge, there has been no previous report of PIE syndrome induced by TJ96. In addition, this is the first report of the detection of ECF activity in lymphocytes induced by an offending drug in vitro.