Activity and content of main microsomal enzymes in liver tissue as well as the patterns of "hexenal" and antipyrine tests were studied after treatment with benzonale (inductor of the monooxygenase system) of rats and rabbits with burns. Distinctly inhibited activity of amidopyrine demethylase and aniline hydroxylase as well as content of protein, cytochromes P-450 and b5 were restored in liver microsomal fraction within 3 and 6 days after intragastric administration of benzonale at a dose of 50 mg/kg into rats with burns. Duration of the effect of hexenal was decreased in benzonale treated animals as compared with the drug sedative effect in control animals with burns. At the same time, reduction of the antipyrine half-elimination period and an increase in its metabolic clearance were observed in rabbits with burns of the III B degree, corresponding to impairment of 6-7% body surface. Benzonale may be efficiently used in complex treatment course of patients with burns in order to restore the liver tissue detoxicating function within early periods, to avoid more effectively the impairments of the patients internal medium, to create optimal biochemical conditions for acceleration of biosynthetic and oxidative reactions in cells.