Nickel, a major environmental pollutant is a known potent nephrotoxic agent. In this communication we report the chemopreventive effect of Terminalia chebula on nickel chloride (NiCl(2)) induced renal oxidative stress, toxicity and cell proliferation response in male Wistar rats. Administration of NiCl(2) (250micromoL Ni/kg body weight) to male Wistar rats resulted in an increase in the reduced renal glutathione content (GSH), glutathione-S-transferase (GST), glutathione reductase (GR), lipid peroxidation (LPO), H(2)O(2) generation, blood urea nitrogen (BUN) and serum creatinine with a concomitant decrease in the activity of glutathione peroxidase (p<0.001). Nickel chloride (NiCl(2)) treatment also induced tumor promotion markers, viz., ornithine decarboxylase (ODC) activity and thymidine [(3)H] incorporation into renal DNA (p<0.001). Prophylactic treatment of rats with T. chebula (25mg/kg body weight and 50mg/kg body weight) daily for one week resulted in the diminution of NiCl(2) mediated damage as evident from the down regulation of glutathione content, GST, GR, LPO, H(2)O(2) generation, BUN, serum creatinine, DNA synthesis (p<0.001) and ODC activity (p<0.01) with concomitant restoration of GPx activity. Thus, the present investigation suggests that T. chebula extract could be used as therapeutic agent for cancer prevention as evident from this study where it blocks or suppresses the events associated with chemical carcinogenesis.