Aim: Monosodium glutamate (MSG) is a universal flavoring booster utilized in the food industry as an additive. This research investigates whether MSG has any effect on the histological and ultrastructural features of the parotid gland of rats and the potential modulatory effects of a famous antioxidant flavonoid Quercetin (QN). Materials and Methods: 24 male albino rats were divided evenly into 3 groups. Group 1 (control group) received orally the vehicle Dimethyl sulfoxide daily (DMSO) for 8 weeks. Group II (MSG group): received a daily dose of MSG (30mg/Kg. b. w.) dissolved in 0.5 ml distilled water through oral gavage for 8 weeks Group III (MSG + QN) received orally monosodium glutamate (30mg/kg. b. w.) dissolved in 0.5 ml distilled water through oral gavage followed by quercetin (10 mg/kg. body weight) in (DMSO) daily for 8 weeks concomitantly. Parotid glands were dissected and assessed histologically by H&E staining and ultra-structurally by Transmission electron microscopy. Results:  MSG group evidenced loss of normal glandular configuration, most of the acini had vacuolated cytoplasm. Nuclear pleomorphism and hyperchromatism, distorted ducts, congested dilated blood vessels and connective tissue heavily infiltrated with inflammatory cells were observed. MSG+QN group exhibited significant amelioration in histological and ultrastructural assessment. Conclusion: Administration of quercetin has protective effects against toxicity caused by chronic MSG intake on parotid glands of rats.