Experiments were made on anesthesized dogs with closed chest to examine the effect of the Soviet antihistaminic drug phencarol on the cardio- and hemodynamics energy metabolism and microcirculatory bed of the myocardium under focal immune injury to the heart. Preliminary administration of phencarol reduced the shifts in the cardio- and hemodynamics and energy metabolism in the myocardium, characteristic for immune injury. The affected area manifested a less marked rop of the systemic arterial pressure, myocardial contractility, the content of adenyl nucleotides, glycogen and phosphorylase activity. There was a considerable decrease in size of the affected area of the left ventricular myocardium.