activity of flavonoid fraction of Terminalia catappa (TcFf) was evaluated against Ehrlich Ascites Carcinoma (EAC) in mice. After 24 hour tumor inoculation the extract was administered for the period of 15,th30,th45th and 60 days. After administration of the last dose followed by 18 h fasting, mice were sacrificed for observation of antitumor activity for each treatment period. The activity of enzymic antioxidants such as Catalase (CAT), Superoxide dismutase (SOD) and glutathione peroxidase (GPX) and the levels of non enzymic antioxidants such as Vitamin A, Vitamin E and Reduced glutathione (GSH) and lipid peroxide (MDA) in the liver homogenate of control and experimental mice were determined. The activities of enzymic antioxidants and the levels of non enzymic antioxidants were decreased in ELA control mice and MDA level was increased. Administration of TcFf significantly altered the antioxidants level and MDA to normal level. The result suggests that flavonod fraction of Terminala catappa exhibited antitumor effect by modulating lipid peroxidation and augmenting antioxidant defense system in EAC bearing mice.