Objective: To evaluate in vivo antioxidant and hepatoprotective activities of the methanolic extract of the root of Cassia singueana in rats following acute and chronic carbon tetrachloride intoxication. Methods: Malondialdehyde (MDA), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and bilirubin as indices of liver damage and lipid peroxidation were detected in rats after intraperitoneal administration of extract (5 mg/kg). Results: The liver, kidney and heart showed significant reduction ( P <0.05) in the levels of MDA from (0.18依0.04), (0.23 依0.07) and (0.26依0.10) nmol/mg respectively in the CCl 4 control to (0.15依0.03), (0.17依0.04) and (0.17 依0.07) nmol/mg protein in groups pre-treated with the extract for three days at 5 mg/kg). Similarly, compared to the CCl 4 control, significant reduction ( P<0.05) in serum AST, ALT and bilirubin as well as in level of total cholesterol and MDA with concomitant increase in HDL cholesterol, superoxide dismutase and catalase levels when CCl 4 -intoxicated rats were treated with Cassia singueana root extract for two weeks. Conclusions: These results suggest that methanolic extract of Cassia singueana contain potent antioxidant compounds that can offer significant protection against hepatic and oxidative injuries. Objective: To evaluate in vivo of alcohol and hepatoprotective activities of the methanolic extract of the root of Cassia singueana in rats following acute and chronic carbon tetrachloride intoxication. Methods: Malondialdehyde (MDA), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and bilirubin as indices of liver damage and lipid peroxidation were detected in rats after intraperitoneal administration of extract (5 mg / kg). Results: The liver, kidney and heart showed significant reduction (P <0.05) in the levels of MDA from (0.23 vs. 0.07) and (0.26 to 0.10) nmol / mg respectively in the CCl 4 control to (0.15 vs. 0.04) and (0.17 to 0.07) nmol / mg protein in groups pre-treated with the extract for three days at 5 mg / kg). Similarly, compared to the CCl 4 control, significant reduction (P <0.05) in serum AST, ALT and bilirubin as well as in level of total cholesterol and MDA with concomitant increase in HDL cholesterol, superoxide dismutase and c atalase levels when CCl 4 -intoxicated rats were treated with Cassia singueana root extract for two weeks. Conclusions: These results suggest that methanolic extract of Cassia singueana contain potent antioxidant compounds that can offer significant protection against hepatic and oxidative injuries.