Influence of subtoxic concentration of manganese chloride in dose equal to LD 50 on condition of plasmatic membranes (model: erythrocytes) and functional activity of cell power (model: the isolated liver mitochondrion of rats) was studied. It was established that manganese chloride in fixed concentration caused authentic augmentation of sorption capacity of erythrocytes towards alcian blue, influenced increasing of their spontaneous haemolysis and activation of peroxide oxidation of lipids. In experiment on the isolated mitochondrion it was proved that manganese chloride caused dissociation of an oxidizing phosphorusling and complete inhibition of respiration in concentrations of 3 and 4,5mM. These dependences testify that subtoxic concentration of manganese can damage the cell energy. Thus, this pilot research indicated damaging effect of manganese on cellular (erythrocytes) and subcellular (mitochondrion) levels which are realized through external functioning of membrane structures and deprived them from restoration.