It was studied an influence of heart peptide complex on myocardial metabolism of intact animals, animals with immune deficiency of heart peptides and acute immobilizing stress. There was no significant changes of biochemical, fibrinolitic and thromboplastine properties of heart tissues by 0.1 and 1.0 mg/kg administration of peptide complex to animals. Treatment with peptide complex leads to a restoration of these properties by immune deficiency. Moreover, peptide complex has stress protective effect by acute immobilization.