Objective To observe the role of short-term use of megestrol acetate in reducing the toxicity of chemotherapy in breast cancer and in improving the quality of life of patients, as well as its impact on neo-adjuvant chemotherapy effects. Methods The effection of adjuvant chemotherapy, toxicity, and the quality of life of 158 patients with breast cancer were investigated by a retrospective control study. The data were statistically analysized by X~2 test. Results There was no significant difference of neo-adjuvant chemotherapy effects between Megestrol acetate + CEF chemotherapy group and vitamin C + CEF chemotherapy group (Megestrol acetate + CEF chemotherapy group was 74. 84%, vitamin C + CEF chemotherapy group was 76.15) ; Megestrol acetate + CEF chemotherapy group had more modest bone marrow suppression and gas-trointestinal reactions and better food intake, weight, KPS score than vitamin C + CEF Chemotherapy group, all the differences being statistically significant (P < 0.05). Conclusion Short-term use of megestrol ace-tate can reduce the adverse effects derived from chemotherapy of breast cancer and improve the quality of life of patients with breast cancer and had no effects on the efficacy of the neo-adjuvant chemotherapy.