A complete explanation of the neurotoxicity that follows kainic acid (KA) injection into the rat striatum is lacking. An assessment of the chronological course after intrastriatal KA injection of the activities of enzymes preferentially concentrated in glia or involved in the detoxification of oxygen metabolites is accomplished. An enhancement of the specific activities of glutathione peroxidase (GP) and catalase is found without an alteration in the specific activity of superoxide dismutase (SOD). There is no increase in the in vivo striatal levels of malondialdehyde, a putative indicator of lipid peroxidation, the expected result of cell membrane damage from oxygen metabolites. Understanding the mechanism and importance of the preferential induction of the activities of the detoxification enzymes will require further study.