ß-Casomorphin is a peptide fragment of casein that exhibits antioxidative and anti-fibrotic activities. In vivo, ß-casomorphin improves high glucose-induced changes in oxidative enzyme secretion and activity. ß-Casomorphin also decreases urinary glucose and protein levels as well as serum creatine and TGF-ß1 in animal models of diabetes, preventing renal interstitial fibrosis.