Chronic alcohol intoxication led to an increase in activity of alcohol dehydrogenase and to decrease -- of aldehyde dehydrogenase and the microsomal ethanol oxidizing system (MEOS) with simultaneous activation of cytochrome P-450 in liver tissue of rats during ontogenesis. Ethanol, which did not affect the enzymatic status of lysosomes within ontogenesis (alpha- and beta-glucosidases, alpha- and beta-galactosidases, alpha-mannosidase, beta-N-acetylglucosaminidase, beta-xylosidase, beta-glucuronidase, beta-N-acetyl galactosaminidase acid RNAase, arylsulfatases A and B, cathepsin D), activated the majority of hydrolases in both embryonal and postnatal periods of development. Distinct increase in lipoperoxidation was detected under conditions of chronic alcohol intoxication.