In industrial countries decreased fertility, occurs especially in men due to increased free radical production. Therefore it is needed to support the antioxidant therapy in indicated cases and to improve the reparative processes of the impaired molecules. There is an increased significance of superoxide dismutase and glutathione peroxidase, which protect sperm from oxidative stress and glutathione and thioredoxin system, which enable the repair of the impaired molecules. To the antioxidants which are also important belong zinc, ascorbic acid, uric acid, albumin, coenzyme Q10, vitamin E, B-complex, folic acid and others. The importance of selenium underlines its presence in glutathione peroxidase, thioredoxin reductase and its relatively high level in reproductive organs. Deficiency of selenium increases the probability ofDNAdamage due to free radicals. A protective effect and the ability to acquire the needed energy to fertilization has the presence of L-carnitine and acetylcarnitine.

        Key words: fertility, male infertility, free radicals, antioxidants, L-carnitine.