Lithium compounds are widely employed in medicine. However, both its positive and negative effects have been revealed. we have tried to evaluate the influence of oral administration of different Li₂CO₃ doses for a period of 8 weeks on the elements of antioxidant status in male rats. The activity of two main antioxidant enzymes: glutathione peroxidase (GPx) and superoxide dismutase (SOD) as well as the concentration of malonyldialdehyde (MDA) - the marker of lipid peroxidation - have been studied. In blood no significant changes of both lipid peroxidation levels and enzyme activity have been found. In tissues enzymes' activities have decreased, significantly in liver (SOD) and kidney (GPx and SOD). no evidence of lithium-induced lipid peroxidation in the tissues has been observed. In the case of brain the Li protective effect against lipid peroxidation has been displayed. In conclusion, the antioxidant status has not been affected in blood and suppressed in tissues as a consequence of Li exposure. The tissue of brain has seemed to be the least attacked organ.