AIM: To investigate the aldose reductase (AR) inhibition capacity of astragalin (AST) against streptozoticin-induced diabetic cataracts (DCs) in rats. METHODS: Ex vivo investigations were conducted by treating the lens of a goat placed for 72h in artificial aqueous humor (AAH) of pH 7.8 at room temperature with cataract-causing substance (55 mmol/L of galactose) and in vivo studies were performed on rats via induction with streptozotocin. AST was administered at different dose levels and scrutinize for DC activity. RESULTS: In diabetic rats, AST improved the body weight, blood insulin, and glucose as well as the levels of galactitol in a dose-dependent way, other biochemical parameters i.e. inflammatory mediators and cytokines, and also suppress AR activity. The level of the antioxidant parameters such as superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) activity were also altered on a diabetic lens after the administration of the AST. CONCLUSION: AST protects against lens opacification to avoid cataracts and polyols formation, indicating that it could be used as a potential therapeutic agent for diabetes.