Abstract: Diisopropylamine salicylate. (DS), a salicylate salt of diisopropylamine, has been demonstrated to possess remarkable and prompt hypotensive effect either in anesthetized rats and dogs by both iv and intra-gastric routes, and in concious Goldblatt renal hypertensive dogs by intragastric administration. Usually the hypotensive action lasts 1.5—5 hours in accordance-with the dose. Acute and subacute toxicity tests showed that the toxicity of DS is rather low.In 10 open-chest mongrel dogs, the hypotensive effect of DS is primarily attributable to the decreased total peripheral vascular resistance (TPVR). In spite of the decrease of dp/dt_max V_CE-CPIP, CI and SI were not significantly lowered. This suggests that the contractility and pump function of the-heart remained intact. The renal and hind limbs vascular resistance of rats and femoral blood flow of dogs were not significantly altered, which indicates that DS does not dilate the blood vessels directly. Similar hypotensive and hemodynamic effects were observed after DS 2 mg/kg given either by iv or intra-vertebral artery injection. After DS 5 mg/kg iv, the cardiovascular effects of nicotine were nullified. It is suggested that the main underlining mechanism of the hypotensive effect of DS may be related to its ganglionic blocking action.