To investigate the effects of N-4-salicyloamide-2-amino-6-piperidinopyrimidine 3-oxide (SALMI) on the blood pressure, this study was carried out in rats, using ethanol as vehicle. When Salmi and its salt were administered into the rat by oral administration or i.v. injection, both of them decreased blood pressure. But when Salmi was administered not more than 200 mg/kg(oral) and 30 mg/kg(i.v.) and Salmi·HC1 was administered not more than 100 mg/kg(oral), they did not significantly influence on the depressor effects of blood pressure.