Aldose reductases are a class of enzymes primarily responsible for converting aldoses into their corresponding alcohols, participating in various reduction reactions within the organism, such as the conversion of glucose to sorbitol. Family members include several subtypes, characterized by a conserved NADPH binding domain. These enzymes are expressed in various cells and tissues throughout the body, particularly abundant in tissues such as the eyes, kidneys, and nerves, where they participate in biological processes such as sugar metabolism and osmotic regulation. The activity of aldose reductases is regulated by multiple factors, and gene expression exhibits tissue specificity. Mutations or dysregulation in expression are associated with complications of diabetes (such as retinopathy and nephropathy), making them potential targets for the treatment of these diseases.