Abstract: OBJECTIVE: To study the preventive and therapeutic effect of ligustrazine against irradiation- induced oxidative stress. METHODS：Mice were exposed to 5 Gy single 60Co-γ irradiation to induce oxidative stress，the concentration of ligustrazine for daily intraperitoneal injection was 31.2 mg/kg to prevent and treat liver injury before and after irradiation. The injection lasted 10 days.We measured the parameters of malondialdehyde (MDA)，superoxide dismutase enzyme (SOD)，catalase (CAT)，reduced glutathione (GSH)，glutathione peroxidase (GPx)，total antioxidation capability (T-AOC) activity in liver. RESULTS：Compared with negative control group，MDA was increased (P<0.05)，the activities of SOD，GSH，GPx and T-AOC were decreased in the liver (P<0.05) after irradiation，while the activity of CAT was not changed significantly (P>0.05). By using ligustrazine，compared with irradiation group，MDA was decreased (P<0.05) and the activities of GSH，SOD，GPx，and T-AOC were increased significantly (P<0.05)，whereas the activity of CAT was not changed significantly (P>0.05). CONCLUSION：Ligustrazine could reduce the oxidative injury induced by irradiation， either as prevention or treatment.

Key words: ligustrazine, irradiation, oxidative stress, antioxidant