Intoxication of NMRI Albino mice with bromobenzene is often followed by the appearance of neurological symptoms. The possibility was investigated that the intoxication results in glutathione (GSH) depletion in central nervous systems as seen in other tissues, and that such a depletion is followed by the development of lipid peroxidation. 18-20 hours after bromobenzene administration (15 mmoles/Kg, p.o.) GSH content of prosencephalic and metencephalic regions was depleted by 39 and 55%, respectively. Lipid peroxidation (measured by the tissue content of malonildialdehyde) was observed only when GSH content reached a threshold value, which was different for prosencephalon as compared to metencephalon (2-1.5 mumoles GSH/g and 1.2-0.7 mumoles GSH/g, respectively). Possible mechanisms underlying the phenomenon are discussed.