Clinical death of animals caused by acute hemorrhage and subsequent resuscitation induce lipid peroxidation in the myocardium accompanied by depression of contractile function and massive efflux of enzymes into the coronary perfusate. Preliminary administration of the antioxidant ionol (100 mg/kg) for 3 days prior to clinical death resulted in a twofold decrease of the lethality during the post-resuscitation period, substantially diminishing activation of lipid peroxidation and efflux of enzymes to the coronary perfusate. Disturbances of myocardial contractility were thus prevented to a considerable degree.