Nigella sativa was found to be effective against experimental Schistosoma mansoni infection. Local application of the seed oil on mice skin before exposure to Schistosoma mansoni infection resulted in complete protection. Oral administration of Nigella sativa after infection resulted in significant reduction in number of adult worms. Egg production was significantly reduced as well. Histopathological study of hepatic granulomas showed reduction in granuloma numbers and diameter. The predominant cells in hepatic granulomas were macrophages while eosinophils were less abundant indicating immunmodulatory effect. Hepatic architecture was preserved indicating antioxidant and anti-hepatotoxic effect of Nigella sativa oil.