3-Hydroxymethyl-beta-carboline (3-HMC) is a benzodiazepine receptor antagonist both in vitro and in vivo. It antagonizes both the anticonvulsant and “anxiolytic” actions of diazepam. 3-HMC decreases sleep and reverses the hypnotic actions of flurazepam. 3-HMC is an active antagonist of the cerebrovascular and cerebral metabolic depression produced by flurazepam and can stimulate cerebral blood flow and cerebral O2 consumption at high doses when given alone. 3-HMC has the ability to specifically antagonize fentanyl anesthesia.