The patient was a 64-year-old woman. She had complained of dyspnea during exercise, productive cough, and pyrexia for two months after treatment to reduce her body weight with a Chinese herbal medicine, bofu-tsusho-san. This symptom worsened gradually, and she was admitted to our hospital for the examination and therapy. Chest radiography and CT scanning on admission showed ground-glass-attenuation with partial consolidation. Replacement of the medicine with treatment with oxygen and few medications for two weeks, made her condition well. The result of DLST for the herbal medicine, Bofu-tsusho-san was negative, but we strongly think it induced pneumonitis. The Chinese herbs ogon and kanzo which are ingredients of bofu-tsusho-san, can cause drug-induced pneumonitis. In conclusion, care should be taken if side effects, hypersensitivity, lung disease, liver injury, or other morbid conditions arise during the use of herbal medicines, because these disorders may lead to serious illness.