Abstract: Studies performed by injection of mature eggs of Schistosoma japonicum into the pulmonary microvasculature of mice revealed that the egg granuloma formation in the lung of the animal pre-sensitized with Schistosoma japonicum SEA occurred much more earlier and were larger in size than that in the unsensitized group. When levamisole was given (5 mg/kg body weight, three times a day for two successive days every week), the size of granulomatous lesions and the number of eosinophils contained were markedly diminished in both sensitized and unsensitized groups examined at 1, 8, 16, 32, 64 and 96th days as compared with the untreated group.