Аннотация:The anticoagulant effects of the peptide Pro-Gly-Arg and its influence on the parameters of blood coagulation in aging rats with depression of anticlotting system (DAS)were investigated in this study. It was founded that PRG-treatment led to a marked enchancement of anticoagulant activityof blood and impact on all phases of blood coagulation, with more alters the activity of protrombinase and the final stage of coagulation slowing the rate of conversion of fibrinigen to fibrin.