摘要:Background and Objective: Liver injury becomes a health threatening problem which needs the search for safe and effective natural liver protection agents. The purpose of this study was to evaluate the hepatoprotective effect of casein glycomacropeptide (CGMP) which contains branched amino acid s against oxidative stress induced in liver damage by CCl4. This was compared with two known polyphenols namely pterostilbene and curcumin. Materials and Methods: Two experiments were carried out. In the first, feeding the additives with different concentrations coincided with CCl4 injection for 5 weeks. In the second, rats were injected with CCl4 for 5 weeks to develop liver fibrosis before starting feeding CGMP and then both feeding CGMP and CCl4 injection were continued for another 5 weeks. Results: Feeding CGMP (100 mg kg1) and pterostilbene (40 mg kg1) significantly improved liver functions. In the second trial, CGMP (150 mg kg1) significantly improved the functions of fibrotic liver and greatly increased the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) than the polyphenols ingredients. CGMP also restored the kidney normal functions after CCl4 treatment. Conclusion: CGMP which is a fraction of milk casein alleviated the rat's oxidative stress caused by CCl4 injection in both experiments. CGMP greatly increased the antioxidant enzymes compared with the two polyphenols and proved to be a hepatoprotective product at 100-150 mg kg1 that can be used to alleviate liver injury at any stage.