Abstract: The present study was designed to examine whether disturbance of the enterogastric circulation of diazepam would obviously affect its inhibitory action on CNS. Intragastric administration of acidic liquid (pH 1) elicited a marked increase in the amount of diazepam in the gastric juice of mice 1 h after iv diazepam, as measured by HPLC method. The effects of ig acidic charcoal (2 g·kg^-1, pH1), neutral charcoal and normal saline on diazeapm induced CNS depression were compared by studying the duration of hypnotic action, inhibition of spontaneous activity, dropping rate in rotating rod test and mortality after iv diazepam (10～40 mg·kg^-1) in mice. The results showed that the animals receiving ig acidic charcoal recovered more rapidly from CNS depression and exhibited lower mortality than the animals in neutral charcol group and normal saline group.