The subcutaneous administration of monosodium glutamate to normal adult male mice at dose levels of 4 and 8 mg/g body weight caused a significant increase in lipid peroxidation level in the arterial tissue. The levels of total sulfhydryl and protein-bound sulfhydryl groups were found to be significantly increased, whereas non-protein-bound sulfhydryl, representing the glutathione level, was significantly decreased. It was also observed that the administration of monosodium glutamate at a dose level of 4 mg/g body weight and above induced oxidative stress by significantly lowering the activities of antioxidant enzymes like superoxide dismutases, catalase, and glutathione metabolizing enzymes like glutathione reductase and glutathione peroxidase in the arterial tissue.