10.22376/ijpbs.2019.10.1.p1-12 Volume 2 Issue 4 2011 (October - December) 7, 12-dimethylbenz (a)anthracene(DMBA) acts as a potent site and organ specific carcinogen by generating various reactive metabolic intermediates leading to oxidative stress. Female Sprague Dawley rats were divided into four groups and each group consisting of six animals. Group I and group IV were vector and drug control. The group II and group III animals were treated with DMBA 20 mg/kg bodyweight to induce mammary carcinoma. Rats received cancer bearing Group III animals were treated with D-Pinitol at the concentration of 30 mg/kg bodyweight for 45 days orally. At the end of the experimental period all the rats were sacrificed. The breast and liver tissues levels of the enzymic and non-enzymic antioxidants were significantly decreased in cancer bearing animals when compared to the control animals. Phase I and II xenobiotic metabolizing enzymes and Lipid peroxide levels (LPO) were estimated. Western blotting analysis showed over expression of Bcl-2 in the mammary tissue of DMBA induced group II rats. From our results, we conclude that D-Pinitol is a potent antioxidant and play a protective role against DMBA induced breast cancer. T. Rengarajan, A. J. Jagadeesan, A. Balamurugan And M. P. Balasubramanian Breast cancer, 7, 12-dimethyl-benz(a)anthracene, D-Pinitol, antioxidants 232-241