Objective: The main objective of this study was to evaluate the antioxidant activity of Traditional Siddha Formulation (TSF) on CCl4 induced liver fibrosis in rats.Methods: In this study, plant materials were collected, shade dried, mixed in equal proportion and extraction process was done to prepare TSF. Liver injury was induced by intraperitoneal injection of 1 ml/kg body weight of both CCl4 and olive oil (2:3 v/v) mixture weekly twice for 8 w. The levels of thiobarbituric acid reactive substances (TBARS), lipid peroxides (LPO), protein carbonyl (PC), superoxide dismutase (SOD), catalase (CAT), Glutathione peroxidase (GPx), glutathione reductase (GR), Vitamin C (VIT C), Vitamin E (VIT E), GSH and Total thiols (TTS) were measured in the liver of experimental rats. Histopathological changes in the liver of experimental rats were assessed for each group using hematoxylin and eosinResults: At the end of the 8-week experimental period, histopathological examination was demonstrated which indicates TSF could attenuate the inflammation and reduced the score of liver fibrosis. The administration of TSF significantly decreased the levels of TBARS (4.11±0.09, p˂0.01), LPO (53.15±0.79, p˂0.01), PC (7.31±0.26, p˂0.01) and significantly increased the levels of antioxidant enzymes such as SOD (7.10±0.16, p˂0.01), CAT (62.14±1.61, p˂0.01), GPx (90.79±1.05, p˂0.01), GR (144.06±1.61, p˂0.01), GSH (35.24±0.82, p˂0.01), VIT C (3.29±0.10, p˂0.01), VIT E (2.42±0.14, p˂0.01) and TTS (15.15±0.21, p˂0.01). Conclusion: TSF inhibits CCl4 intoxicated hepatic fibrosis in Wistar Albino rats which may be due to the action of synergistically active phytochemicals present in the formulation. Enzymatic and non-enzymatic antioxidant enzyme levels were found to be increased in the treatment group which may be related to the therapeutic effect of TSF
