In the present study, preventive and protective effects of Ocimum gratissimum in ethanol-induced hepatotoxicity are assessed in albino rats. A methanol extract of O. gratissimum leaves is prepared, with a yield of 3.5% (w/w) of the dry weight of leaves. Graded doses of the extract (10, 20, 40 and 80 mg/kg body weight), together with ethanol (5 gm/kg body weight) are administered orally to experimental groups for 30 days. Normal control rats receive distilled water only, while rats in an alcohol control group (AC) receive ethanol only for 30 days. O. gratissimum reduced the level of thiobarbituric acid reactive substance in all experimental groups (E1-E4). Alanine transaminase and aspartate transaminase levels fell in all experimental groups (E1-E4), but this reduction was significant only in groups E3 and E4 (P < 0.05), indicating inhibition of lipid peroxidation by free radicals generated after ethanol metabolism. Levels of antioxidants also increased. Ascorbic acid and glutathione levels increased in all experimental groups (E1-E4; P < 0.05 and P < 0.01, respectively). A significant increase in catalase (P < 0.05) was noted only in group E4, although an upward trend was noted in all experimental groups. This study shows that O. gratissimum prevents free radical damage to the liver and thus protects the organ from oxidative stress.