Background and objectiveComplications in diabetes mellitus are associated with free radicals and oxidative stress. The human body prevents these complications through antioxidant defense mechanisms. The aim of the study was to investigate the effect of aqueous seed extract of Securigera Securidaca on erythrocyte catalase activity in type1 diabetic rats. MethodsAt the present interventional study thirty male wistar rats were used. Animals were divided to two groups including normal and diabetic (n=15 per each group).Each group was divided further to control and experimental subgroups. The experimental subgroups were received 100 and 200 mg/kg/day of the plant extract intraperitoneally. After thirty days administration, blood sample was directly collected from the heart and erythrocyte catalase activity was assessed.Resultscatalase activity decreased in diabetic control group significantly (P=0.002).Furthermore, catalase activity in groups treated at two doses of 100mg/kg and 200mg/kg was significantly different as compared to control group(P=0.003).ConclusionThe aqueous seed extract of Securigera Securidaca probably could be effective in decreasing diabetic complications through improvement of antioxidant response by altering catalase activity and consequently reducing oxidative stress.Keywords: Catalase; Diabetes Mellitus, Type1; Oxidative Stress; Antioxidant Securigera Securidaca