ABSTRACT:The article presents research of structural and functional changes in the liver in the conditions of modeling of micronutrient deficiencies in the organism of experimental animals with subsequent inclusion of complex minerals into their food ration. The object of the study was the liver of rats «Wistar». The elemental composition of biological substrates has been studied using atomic emission and mass spectrometry (ICP-AES and ICP-MS) in the test laboratory ANO «Center for Biotic Medicine». It has been established that the addition of selenium to the ration increases the concentration of this element in the liver by 15,0% (p≤0,05) against the background of lowering nickel by 50,0% (p≤0,05) in the experimental group I relative to control. When you turn on zinc into the ration, the concentration of it increases by 14,3% (p≤0,05) in the experimental group II relative to the control. Inclusion of iodine in the ration contributed to the increase of the iodine concentration by 4,52% in the experimental group III relative to the control group. Thus, the intake by the animal organism of toxic elements (lead and cadmium salts) leads to a change in the structural elements of the liver, resulting in depletion of hepatocyte in glycogen, or its complete disappearance, in offensive vacuolization and necrosis of hepatocytes and in changes in vessels diameter microvasculature, i.e. structural and functional changes in the liver are identified. Introduction into the ration of complex of essential trace elements (I, Se, Zn) involves an increase in functional activity of the liver.