One-month therapy with trimetazidine sharply decreased the content of free radical oxidation products, lipid peroxides and malonic dialdehyde, in atherogenic low-density lipoproteins in patients with coronary heart disease. Activity of glutathione peroxidase utilizing lipid peroxides in the plasma markedly increased during trimetazidine therapy. The data suggest that trimetazidine not directly interacting with free radicals attenuates the adverse effects of intensive free radical oxidation in coronary heart disease. This effect is mediated via activation of antioxidant enzymes, which diminishes negative consequences of ischemia.