So far various drugs have been used in an attempt to prevent or reduce cisplatin (CDDP)-induced peripheral neuropathy. Of those tried reduced glutathione (GSH) is one of the most promising. Its effectiveness has already been demonstrated by means of morphological methods in CDDP-treated rats in which high doses of GSH (up to 1200 mg/kg) were given. In the current study neurophysiological and morphological methods were used to evaluate the effect of low doses (150-300 mg/kg) of GSH i.p. on the peripheral nervous system of the rat. Four groups of 8 female Wistar rats were treated as follows: (A) CDDP 2 mg/kg i.p. weekly for 9 courses; (B) same as (A) plus GSH 150 mg/kg i.p. weekly; (C) same as (A) plus GSH 300 mg/kg i.p. weekly; (D) same as (A) plus GSH 150 mg/kg i.p. on the day of DDP injection followed by 150 mg/kg/day over the next 2 days. Eleven age-matched untreated rats were used as controls. Sensory conduction velocity was recorded in the tail nerve and morphologic and morphometric examinations were performed on the dorsal root ganglia neurons (L4-L6) in each animal. The results demonstrated that the neurophysiological and pathological changes induced by CDDP administration were less severe in rats co-treated with GSH. No significant differences could be related to the 3 different regimens of GSH co-treatments. This experiment confirms that GSH is able to reduce the neurotoxicity of CDDP and that it is effective even at doses as low as those used in the present study.