Through the experiment model of the myocardial ischemia/reperfusion and lipoidaemia in rat, both of them obviously induce membrane injury: a drop of membrane phospholipids, an increase in content of free fatty acids, cholesterol and cholesterol/phospholipid ratio, a decrease in membrane lipids fluidity and activity of membrane enzymes (Ca²⁺, Mg²⁺-ATPase). These aterations perhaps related to the increase of lipids hyperoxidation induced by free radical and exchange of lipids.