Abstract: Objective To investigate the effect of benzoyl peroxide(BPO) as a flour bleeding agent on liver tissue of mice.Methods Sixty-four Kunming mice were randomly divided into four groups:control group,low,moderate,and high dose BPO groups.The mice in exposure groups were administered with 50,100,and 200 mg/kg BPO by gavage for 6 weeks.Then the content of malondia ldehyde (MDA) and activities of glutathione peroxidase (GSH-Px),superoxide dismutase(SOD),Na+K+-ATPase,Mg²⁺-ATPase,and Ca²⁺-ATPase in the liver were determined.Results The activity of SOD in high and moderate BPO groups were 40.15±7.13,46.01±6.69 U/mg·prot,respectively,with significant differences compared to that of the control group(53.15±6.55 U/mg·prot,P < 0.05).The difference in the content of MDA was statistically significant between high BPO and control group (1.93±0.37 vs 1.57±0.33 nmol/mg·prot,P< 0.05).Compared with the control group,the activities of Mg²⁺-ATPase and Ca²⁺-ATPase in high BPO group decreased statistically (1.58±0.11 vs 1.48±0.09 molPi/mg·prot/huor,P < 0.05).There was no significant difference between BPO groups and control group in the activity of GSH-Px (P > 0.05).Conclusion BPO has certain harmeffect on antioxidant status and the activity of Ca²⁺ Mg²⁺-ATPase of liver tissue in mice.