Abstract: Total alkaloid of Picrasma Quassioides (APO) given intravenously (1mg/kg) to anesthetized dogs markedly decreased the blood pressure (P<0.001). APQ given by oral administration to normal or renal hypertensive rats also markedly decreased the blood pressure (P<0.05). APQ was found to be able to slow the heart rate in dogs, improve the myocardial nutritional blood flow in mice and inhibit the sympathetic discharges in rabbits. In addition, acute toxicity tests in mice showed low toxicity. Subacute toxicity tests in rats showed that it did not significantly influence the liver and kidney functions.