Concentrations of amino acids such as glutamate(Glu), glutamine(Gln), gamma-aminobutyric (GABA), glycerin(Gly) in rat cerebral cortex were measured by o-phthaldialdehyde method to clarify alterations of these amino acids in infectious brain injuries(IBI). The results were that Gln and GABA in groups treated by bordetella pertussis suspension(BP) 4h were increased compared to those in the group treated by the normal saline(NS) or the operative control(OC) and a positive correlation with water content or Evans blue content, respectively. In the 24h BP group, Gln was still increased; GABA and Gly were decreased compared to those in the NS or OC group. The findings suggest that GLu, Gln, and Gly play an important role and GABA may be a marker of injury in pathogenetic mechanism of IBI induced by BP.