The effect of acute hemorrhage on the functional status of microsomal cytochrome P-450-dependent hepatic monoxygenases and the impact of induction of these monoxygenases on the survival of posthemorrhagic male Wistar rats. Acute blood loss of the rats, which caused 50% deaths led approximately to a double decrease in the hepatic activity of 77-ethoxycoumarin-O-deethylase (ECOD). Induction of hepatic monoxygenases by phenobarbital in a dose of 80 mg/kg for 3 days, which caused a 2.4-fold increase in the activity of ECOD as compared with the controls, prolonged the survival rate of posthemorrhagic rats from 50 to 85%.