Background. Currently, the growing incidence of toxic lesions of the liver is associated with industrial chemicalization and uncontrolled use of hepatotoxic drugs in everyday life. There are about one thousand drugs with high or low hepatotoxicity, such as anti-TB drugs. Objective. In this research we studied the intracellular enzymes activity and bile formation function of the liver in rats of different ages in cases of tuberculostatic (isoniazid and rifampicin) affection and chromium (potassium dichromate) intoxication. Methods. The experimental affection of rats of different ages was performed by combined injection of hexavalent chromium compounds (a solution of potassium dichromate, 3 mg/kg), isoniazid (0.05 g/kg) and rifampicin (0.25 g/kg). On the 7th and 14th days the rats were injected with enterosorbent Sorbex (150 mg/kg). Enzyme markers activity of the liver was evaluated due to alanine and aspartate aminotransferases (ALT and AST) and alkaline phosphatase (ALP) rates. Bile formation function of the liver was evaluated by total bilirubin and bile acids content in blood. Results. The disorders in hepatocytes plasma membranes permeability were defined by the increased rates of ALT, AST and alkaline phosphatase in blood serum which were decreased in the liver. It was determined that total bilirubin and bile acids content in blood serum of the affected animals increased. It influenced hepatocytes excretion in bile capillaries and caused cholestasis and revenues decrease in bile. Conclusions. The most significant metabolic disorders in cases of chrome-isoniazid-rifampicin affection were defined in immature and senior animals in comparison with mature animals.