Abstract: Forty-seven patients with schistosomiasis were treated orally with nithiocyamine at the total dosage of 350 mg/kg for 3 days. The blood concentration of the drug reached 1.56+0.18μg/ml 48 hours after initiation of oral administration. By the 16th day after treatment, the blood drug concentration was still 0.1μg/ml. In the blood, plasma took up more drug than the blood cells and other blood constituents. Urinary excretion in patients usually lasted more than 19 days after three consecutive. dosages.Determination of nithiocyamine in tissues of one patient at autopsy showed that the concentrations in the liver, kidney, heart and spleen were higher than those in the muscle, brain, fat and plasma.The drug when given orally to rats at dosage of 100mg/kg/day for 7 days induced a marked reduction of bile secretion through the liver and a marked increasein bilirubin and icterus index in the Serum of rats.