Cigarette smoke leads to the production of a large number of different free radicals, especially superoxide, alkoxy- and alkyl- radicals and free hydroxyl radicals. Antioxidant defence must be complex, i.e. a mixture of different substances. Smoking injures intracellular antioxidant balance, decreases the levels of glutathione, ascorbic acid, glutathione peroxidase and catalase. -carotene, lutein, zeaxanthin and others are decreased in the extracellular fluid. The most dangerous complications of smoking in the respiratory pathways are inflammatory reactions, proliferation of cells, carcinoma cells, emphysema, and chronic obstructive pulmonary di-sease. Decrease of antioxidants, increase of asymmetric dimethylarginine, of lipoperoxidation, of endothelin and peroxynitrite are the most important laboratory findings of damage. Another complication is endothelial dysfunction. Nitric oxide production is decreased, as is the dilatation of vessels; apoptosis of endothelial cells is increased, and the differentiation and function of endothelial cells is impaired. There are many causes for the acceleration of atherosclerosis, but oxidative stress is one of the most dangerous. Oxidated and altered LDL-cholesterol contributes to the formation of foam cells. Activated myeloperoxidase produces hypo-chloric acid, the substráte for which is not only hydrogen peroxide, but also thiocyanate from tobacco. Free radicals oxidate and mutate DNA leading to an increased incidence of carcinomas. Free radicals and reactive oxygen species decrease the fertility of spermatozoa, and in pregnancy can damage the development of the foetus, they also encourage the origin of neurological and psychiatrie diseases (Parkinson's disease, Alzheimeťs disease, hemodynamic and inflammatory diseases of the brain, they evoke the pain etc). Macular degeneration of the eyes, certain dental, gastrointestinal, renal, orthopaedic and skin diseases, and damage to cochlear epithelial cells due to noise are some of other possibilities of damage due to cigarette smoke.

        Key words: smoking, free radicals, antioxidants, oxidative stress, diseases induced by cigarette smoke