A 25-year-old woman presented with a high temperature, cough and dyspnea three days after taking sho-seiryu-to, a Chinese herbal preparation, for a cough and throat pain. A chest X-ray film and computed tomography (CT) scan revealed diffuse infiltrative shadows in both the middle and lower lung fields. Arterial blood gas analysis showed hypoxemia (PaO2 43Torr under room air). The white cell count was 40,800/mm3, with eosinophilic cells accounting for 56.5% of the cells. The patient was treated with methylprednisolone under a diagnosis of drug-induced pneumonia and the administration of sho-seiryu-to was discontinued. Immediately after the prednisolone administration, her chest X-ray film findings, clinical symptoms and laboratory data markedly improved. A lymphocyte stimulation test for sho-seiryu-to using peripheral lymphocytes was positive. In 29 cases of herbal medicine-induced pneumonia reported in Japanese medical literature over a 10-year period, sho-saiko-to has been the predominant cause of drug-induced pneumonia. This is the second case of sho-seiryu-to-induced pneumonia.