The known literature data concerning the mechanisms of molecular action of vitamin E in biological membrane systems are reviewed. The role of vitamin E, possessing a broad range of biological activities, as a universal stabilizer of biological membranes in normal oxygen metabolism and peroxidation, and also in disorders of normal metabolism resulting in pathological alterations, has been discussed. The participation of vitamin E in redox reactions taking place in lipid media, its interaction with singlet oxygen, free fatty acids and enzyme systems are considered. Physiological effects of vitamin E and its ability to prevent numerous pathologies are also considered. Vitamin E was concluded to be a universal participant of antioxidant defence reactions in biological membranes, since it acts at all stages of membrane oxidative damage.