The dynamics of met-and leu-enkephalin content in the brain cortex and hypothalamus of rats with severe burn shock caused by 50% burns by boiling water were studied. A tendency towards burn-induced growth in leu-enkephalin hypothalamus level was observed, with the content of met-and leu-enkephalins in the hypothalamus significantly increasing 30 min later. Met-enkephalin content in the brain cortex also rises. 2 hours later the changes are less pronounced, with met-enkephalin hypothalamus level remaining elevated. The adaptive nature of changes, mobilization of endogenous anti-pain defensive mechanisms in severe burn shock and the role of hypothalamus structures in this process are suggested.