The methods of biochemical analysis revealed, that one of the complications prolonged use of glucocorticoids is the development of oxidative stress on the tissue level. Experiments on the rats proved, that the kidney together with other organs are the most sensitive to active oxygen metabolites. In case of study samples rat kidney with glucocorticoid-induced oxidative stress in transmitted light allows to discover the violation structure components of glomerular basal membrane, walls of capillaries vascular glomeruli, epithelium of distal convoluted tubule. Using atomic-emission analysis of kidney tissue homogenates indicates a violation of Na / K homeostasis, filtration and reabsorbtion functions of this organ. Addition to these elements, which are of decisive importance in the regulation of water-salt homeostasis, found change in the content of Cu and Fe, included in the active sites of key antioxidant enzymes.