The central effects of carboxyethyl-gamma-aminobutyric acid (CEGABA) have been studied both in rabbits and in the guinea pig myoclonus model. This drug caused EEG synchronization and behavioural sedation both after intravenous (i.v.) and intracerebroventricular (i.c.v.) administration in a dose-dependent manner, in rabbits. CEGABA showed a protective action against myoclonus induced by means of L-5-HTP in young guinea pigs. These data substantiate the hypothesis that CEGABA is a drug active on the central nervous system and probably exerts its action by strengthening cortical inhibition and/or directly acting on lower brainstem.