Objective To study the in-vivo antioxidation effect of citrus flavonoids.Methods The aged mice were induced by subcutaneous injection of D-galactose (1 g?kg-1?d-1)for 6 weeks and simultaneously received gastric infusion of citrus flavonoidsat at different dosages(200 mg?kg-1?d-1 or 600 mg?kg-1?d-1)for 6 weeks.After treatment,the SOD activity and the MDA content in liver and skin as well as the content of hydroproline (HYD) in skin were measured.Results Citrus flavonoids increased the SOD activity significantly (P