The present study aimed to evaluate the antitumor chemotherapeutic potential of Ginkgo biloba extract against breast carcinogenesis by Ehrlich ascites carcinoma implanted in Swiss albino mice. Chemotherapy was evaluated by monitoring tumor incidence and size, as well as analyzing the status of (a) the biochemical profile related to oxidative stress, including; total antioxidant capacity (TAC), glutathione reductase (GR) activity, glutathione-S-transferase (GST) activity, superoxide dismutase (SOD) activity, catalase (CAT) activity and lipid peroxidation (MDA), markers of renal and hepatic toxicity (urea, creatinine, alanine transaminase). Histopathological changes indicated tumor inhibition and neovascularization after treatment. Overall, these results suggest that treatment with Ginkgo extract provides antioxidant protection as well as high chemotherapeutic efficacy against breast tumors implanted with stem cells.