Acute and subacute toxicity tests of plasminogen pro-activator (PPA) were carried out by i.v. administration in cynomolgus monkeys.In the acute toxicity test, PPA was administered at 55,000 and 11,000 units/kg.Intermittent bleeding was observed from 6 h after administration of PPA 55,000 units/kg.In hematol. examinations, decreases of hematocrit (Ht), Hb, erythrocytes (RBC) and platelets were found until the 3rd day after administration.In pharmacol. and pathol. examinations, changes due to bleeding were found.In the subacute toxicity test, PPA was administered for 90 days at 1,200, 360, and 120 unit/mL/kg.Hemorrhage in s.c. tissues, hematoma in the abdominal wall, blackish feces, and occult blood in the urine were observed dose-dependently.In hematol. examinations, decreases of Ht, Hb and RBC, and increases of reticulocytes were dose dependent.In coagulation and fibrinolysis examinations, fibrinosis due to the pharmacol. effects of PPA (decreases of fibrinogen, plasminogen and α2-plasmin inhibitor, and increases of fibrin/fibrinogen degradation products were dose dependent.