Abstract: Objective To investigte antioxidant effect of various dosages of aplusin on aged mice.Methods The subacute ageing model of mice were made by back neck subcutaneous injection of Dgalac to secontinuo uslly.The oxidative DNA dam age of peripheral lymphocytes induced by H2O2 was analyzed by SCGE.O⁶ methy guanine(O⁶ MeG)was measured by high performance capillary zone electrophoresis.The content of malondialdehyde(MDA),activities of superoxide dismutase(SOD),and glutathione peroxidae(GSHPx)in the serum were tested.Results There was nosignificant difference in DNA spontaneous damage of peripherallym phocytes between treatment and control groups.There was a significant decreasing tendency of oxidatice DNA damage of peripherallym phocytes in 40,80 mg/kg·bw aphysin and Vit E supplement groups exposed to 10 mol/LH2O2 compared with blank control group(P<0.05).The conents of O⁶ MeG in plas ma of 40,80mg/kg aplysin and Vit E supplement group were significantly lower than that of the blank control(P<0.05).The SOD and GSHPx acticities in 40,80m g/kg aply sin and Vit E supplement groups were higher than that of the blank coutrol(P<0.05).The contents of MDA in all supplement groupswere significantly lower than that of the blank control(P<0.05).Conclusion The study indicated that aplysin could engange in antio xidantive acticities,strengthen the activities of antioxidative enzyme SOD and GSHPx,and lower the level of MDA.A ply sin can also decrease DNA damage effectively in the aged mice.