Effect of sodium hydroxybutyrate on lipid metabolism was studied in experimental infarction of rabbit myocardium. Administration of 80 mg of sodium hydroxybutyrate per kg of body mass caused a decrease of free fatty acids content in the infarction zone, in surrounding zones and in blood. Treatment of the experimental animals with sodium hydroxybutyrate normalized distinctly the phospholipid composition of the ischemized myocardium. Content of phosphatidyl choline, phosphatidyl ethanolamine and cardiolipine was increased in the infarction zone and in surrounding zones of myocardium. Concentration of lysolecithines was decreased in the both zone studied. In the animals treated with sodium hydroxy butyrate after the infarction output of myocardial creatine kinase into circulation was decreased.