In the present study, some toxic effects of cisplatin are evaluated in rats. It was also investigated whether S-carboxymethylcysteine (S-CMC), a free radical scavenger, protects the experimental animals from the toxic effects of cisplatin. The 1st, 2nd, 4th and 5th groups received physiological saline, dimethyl sulphoxide, and S-CMC (100 and 500 mg/kg i.p.) for 3 days, respectively. The 3rd group received cisplatin (5 mg/kg i.p.) 12 h before sacrifice. The 6th and 7th groups received S-CMC (100 and 500 mg/kg i.p., respectively); additionally, these groups received cisplatin (5 mg/kg i.p.) 12 h before the rats were sacrificed. 5 mg/kg cisplatin decreased significantly serum creatinine and glutamic-oxaloacetic and glutamic-pyruvic transaminase levels as well as leucocyte counts. Although S-CMC did not change the effects of cisplatin on creatinine and liver enzyme levels, it eliminated the effect of cisplatin on leucocyte counts. Cisplatin increased significantly urinary creatinine level and creatinine clearance. Cisplatin caused some histological changes in kidney and liver.