['Ocimum gratissimum is a vegetable plant of wide nutritional and medicinal aŕpplications in Nigeria and in some other parts of the world.', 'The effect of oral administration of aqueous leaf extract of O. gratissimum on the activities of plasma and hepatic anti-oxidant enzymes in rats was investigated.', 'Two different doses of aqueous leaf extract of O. gratissimum (0.2 mg/g and 0.4 mg/kg body weight) were separately administered orally daily into rats for 4 weeks. The rats were sacrificed after 30 days of administration, blood was collected and the liver excised. The liver was homogenized, while plasma and hepatic anti-oxidant enzymes, namely catalase (CAT), superoxide dismutase (SOD) and glutathione -S- transferase (GST) specific activities were assayed.', 'Results of the study showed a significant (p < 0.05) increase in the specific activity of both plasma and hepatic CAT and SOD in a dose dependent pattern. However, the effect of the leaf extract on GST specific activity was not significant (p > 0.05) as compared to the control. There were no significant changes in the plasma and liver protein concentrations in rats administered the extracts as compared to the control.'] Does aqueous leaf extract of Ocimum gratissimum potentiate activities of plasma and hepatic antioxidant enzymes in rats?