The safety of using monosodium glutamate (MSG) as a food flavour enhancer has generated much controversy locally and globally. Quercetin (QU), a natural compound of multiple origins, has broad biopharmacological effects as an antioxidant and a hepatoprotective substance. Therefore, the present study was designed to investigate the modulatory effect of oral doses  of QU on the microscopic liver changes and liver oxidative stress induced by MSG. Thirty male albino rats were divided  into five groups, each of six rats: group I received distilled water, group II received corn oil, group III was administered QU (14 mg/kg body weight), group IV was treated with aqueous MSG (15 mg/kg body weight), and group V was given MSG (15 mg/kg body weight) simultaneously with QU (14 mg/kg body weight), orally and daily for 30 days. Numerous deleterious histological and ultrastructural changes were induced by MSG in concomitant with a significant increase in the activities of serum aminotransferases (ALT and AST) and the level of hepatic lipid peroxidation, while decreases in superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities, as well as reduced glutathione (GSH) concentration were also recorded. QU administration amended the liver histological lesions and ultrastructural changes induced by MSG via decreasing significantly the level of hepatic lipid peroxidation and the leakage of serum aminotransferases, and improving the hepatic antioxidant defence system. In conclusion, QU showed a hepatoprotective activity against the potential toxicity of MSG food flavour.