Intravenous proantocyanidin isolated from Alhagi pseudoalhagi (M. B.) Desv, 5-10 mg/kg, has no effects on the general hemodynamics and cardiac contractility of intact rats and rabbits. The agent given to animals with experimental myocardial infarction reduces serum creatinine phosphate levels and lipid peroxidation both in the myocardium and serum, as estimated by the amount of malonic dialdehyde and dienic conjugates), normalizes free fat acid content and cardiac phospholipid spectrum. At the same time the size of a myocardial necrotic zone became diminished.