The perfusion of the cat brain was performed according to the method of Ikeda, H. who modified the method of Geiger, A.. Electrocorticogram, cerebral blood flow, and biochemical and pharmacological findings in the case of the administration of GABOB were obtained respectively by the use of the perfusion method, and then the correlation of each appearance waseinvestigated. 1). Electrocorticogram of perfused cat brain was supressed by administration of GABOB in all cases. 2). The rate of cerebral blood flow, oxygen and glucose consumption and the liberation of lactic acid were all increased by the same treatment. 3). The above mentioned changes were reversible, namely those turned to normal soon after the interruption of GABOB administration. 4). All reflexfunctions as conjunctival reflexes, corneal reflexes, pupillary reactions and pain sensations, and respiration rate, blood pressure, electrocardiogram had represented no remarkable change. Accordingly, any activating effects of GABOB on ehe function of the perfused cat brain was not observed in all experiments.