Abstract: The pharmacological studies on essential oil of Asarum forbesii Maximd monstratedthat it had a markedly depressant effect on the central nervous system. The essential oil could apparent!y decrease the spontaneous activity in mice (0.15ml/kg i,p.) and potentiate the hypnotic action of pentobarbital or thiopental(O.025 ml/kg i.p.). When injected intravenously (0.05 ml/kg), it caused anaesthetic effect in rabbits.It also antagonized the convulsion induced by e1ectricity or metrazol in mice. It could not antagonize the toxic effect of amphetamine in mice. In addition, essential oil of Asarum forbesii Maxim could also increase the tolerance against anoxiain in mice and reduce body temperature in rats.