Gastrodia elata is a medicinal plant which has been used as anticonvulsant in Korea, Japan and China. This study was conducted to examine the action mechanism of Gastrodia elata centering around the change of GABA and glutamic acid level in brain while observing the anticonvulsive effect in PTZ-induced seizure model. Seizures were reduced effectively by pretreatment of ether soluble part of methanol extract of Gastrodia elata. The pretreatment of ether soluble part inhibited not only the decrease of brain GABA level but also the increase of brain glutamic acid level observed in PTZ model of convulsive dose. Although there was not any change in glutamic acid level, the same development was also observed in the model of subconvulsive dose. From above results, it seems that the anticonvulsive component of Gastrodia elata is lipophilic, and its action mechanism is originated from both control action of GABA level and inhibition of glutaminergic neurotransmission.