Objective To explore the oxidative inducibility of oh 8Gua glycosylase in mammalian tissues. Methods Treated with potassium bromate (KBrO-3), the activity changes of this enzyme in the kidney and the liver of rats were measured and compared by HPLC/ED. Results With a single dose of KBrO-3 (80 mg/kg,ip), the activity in the kidney was found to increase significantly at 3h. At 6h, activity peaked, showing a 6-fold increase over that at zero time. Thereafter, it decreased and returned to its zero time level at 12h. With increasing doses of KBrO-3 (up to 160 mg/kg,ip),activity increased linearly with increased dosage, and over 40mg/kg, the activity increased to a level significantly higher than that in the control. But no significant changes were observed in the liver on the same conditions. Conclusion oh 8Gua glycosylase can be induced oxidatively in mammalian tissues and it implies that the repair of oh 8Gua residues in DNA is a process important for the survival of organisms in an aerobic environment.