The administration of methamphetamine to experimental animals results in damage to dopaminergic neurons. The hypothesis that methamphetamine-induced neurotoxicity is mediated by reactive oxygen species was evaluated. It was found that acute administration of methamphetamine (5 and 15 mg kg(-1)) resulted in production of oxidative stress as demonstrated by decreased glutathione and increased oxidized glutathione levels in the rat striatum and prefrontal cortex. These changes in glutathione and oxidized glutathione levels were dose-dependent in striatum but not in prefrontal cortex. In conclusion, the results of present study provide further evidence in support of the notion that oxidative stress may play an important role in the methamphetamine-induced neurotoxicity.