Abstract: Antimonyl quinine hydrochloride (AQH) is a complex prepared by mixing alcoholic solutions of quinine hydrochloride and antimony trichloride in a molecular proportion of 1:2.Oral administration of this complex has been shown to be effective for Schistosomiasis japonicum in experimental animals as well as in patients. When AQH was given orally to rats,antimony disappeared very slowly from the gastrointestinal tract.About 90% of the administered antimony was still present in the gastrointestinal tract after 8 hours.When a ligature was applied to the part between the duodenum and the pylorus before AQH was administered by stomach tube,large amounts of antimony could be recovered from the intestinal tract within a few hours.Antimony was found in the bile a few minutes after AQH was given to rats.Antimony was excreted mainly in the feces,less than 1% was excreted in the urine.Twenty four hours after oral administration of AQH to rats,antimony could be found in all tissues.Beside the gastrointestinal tract,the highest level was found in the liver,lower levels were found in the kidney and spleen;the antimony levels in the lungs,heart,brain and blood were very low. Apparently,the slow disappearance of antimony from the gastrointestinal tract does not mean that the absorption of AQH is slow.It seems that antimony is absorbed fairly rapidly and is excreted in the feces at least in part via the bile.