The peroxide reaction in mouse kidney was examined in order to determine the relationship between the lipid peroxide reaction caused by SART (specific alternation of rhythm in temperature) stress and that caused by drug administration. After exerting SART stress for one wk on 6-wk-old male ddY mice (stress group), the peroxide reaction generated by the administration of a single dose of cis-diamminedichloroplatinum (cisplatin: CDDP, 10 mg/kg, i.p.) into SART-stressed mice (stress + CDDP group) was compared with the reaction of CDDP-administered nonstressed mice (CDDP group), saline-administered nonstressed mice (saline group), and saline-administered SART-stressed mice (stress + saline group). Lipid peroxidation in the kidneys was significantly higher in the stress group upon cessation of stress exertion than in the normal group. However, no significant difference in the lipid peroxide level after administration of CDDP was observed between the CDDP groups. The renal glutathione levels were significantly different between the CDDP groups and the saline administered groups. These results indicate that the peroxide reaction is generated in the kidneys by stress, but stress has no effect on the peroxide damage caused by CDDP administration. However, the contribution of stress to renal function impairment requires further evaluation.