BACKGROUND Rutin, a polyphenolic flavonoid, was investigated for its protective effects against the KBrO(3) induced renal injuries in rat. METHODS Group I was control (untreated), group II was given saline 0.5 ml/kg bw (0.9% NaCl), group III was administered KBrO(3) (20 mg/kg bw) intragastric twice a week for four weeks. Rutin was administered to group VI (50 mg/kg bw) and Group V (70 mg/kg bw) along with KBrO(3) (20 mg/kg bw) while group VI was given rutin (70 mg/kg bw) alone twice a week for four weeks. Protective effects of rutin on KBrO(3)-induced nephrotoxicity in rats were determined for biochemical parameter of urine, and serum, various antioxidant enzymes, DNA and histopathological damages in kidneys. RESULTS The level of urinary red blood cells, leucocytes count, specific gravity, urea, creatinine and urobilinogen was increased (P<0.01) whereas creatinine clearance was reduced. Serum level of protein, albumin, globulin, nitrite, creatinine and blood urea nitrogen (BUN) was significantly increased (P<0.01) by KBrO(3). Marked histopathological lesions, elevated DNA fragmentation and AgNORs count in renal tissues was determined. Activity of antioxidant enzymes; catalase, superoxide dismutase, glutathione peroxidase, glutathione-S-transferase, glutathione reductase, and reduced glutathione contents were decreased (P<0.01) while thiobarbituric acid reactive substances were increased (P<0.01) with KBrO(3) treatment in kidneys. DNA ladder assay was intimately related with the DNA fragmentation assay. Telomerase activity was found positive in the KBrO(3) treated kidneys. Treatment with rutin effectively ameliorated the alterations in the studied parameters of rat. Rutin administration alone to rats did not exhibit any significant change in any of the parameters studied. CONCLUSIONS These results suggest that rutin works as an antioxidant in vivo by scavenging reactive oxygen species and this serves to prevent oxidative renal damage in rat treated with KBrO(3).