The reaction of ozone with polyunsaturated fatty acids from the surfactant factor and pulmonary epithelial cells produces different reaction products which can cross the alveolar-capillary barrier and reach distant structures. Although only a few papers claim extrapulmonary changes in animals exposed to this gas, some neurological deficits, such as complaints of fatigue, lethargy, headache in humans, as well as significant disarrangements in the sleep pattern related to biochemical changes in the brain have been referred to in animals exposed to ozone. In the present review, the molecular configuration and the reaction of ozone at different lung levels are related to impairment at the respiratory and blood systems, in order to elucidate the mechanisms by which this gas or its reaction products, such as free radicals, prostaglandins and others can cross the alveolar-capillary and hemato-encephalic barriers, and to explain those neurological effects.