【Abstract】 Objective To study the clinical efficacy of Huaier granule in postoperative chemotherapy of breast cancer and to treat cyclooxygenase 2 (COX2), pancreatic cancer related antigen (CA199), Carcinoembryonic antigen (CEA) and vascular endothelial growth factor (VEGF). Methods 96 patients with radical mastectomy from December 2013 to December 2016 were randomly divided into control group and experimental group, 48 cases in each group. The control group was treated with FEC (fluorouracil, epirubicin, cyclophosphamide) on the basis of routine treatment. The experimental group was treated with Huaier granules based on the control group. The incidence of adverse reactions was observed and the levels of serum COX2, CA199, CEA and VEGF were observed. Results After treatment, the effective rate (6250%) in the experimental group was significantly higher than that in the control group (P＜005). The incidence of adverse reactions was significantly lower in the experimental group than in the control group (6042%), gastrointestinal reaction (1250%) and abnormal liver function (208%), the difference was statistically significant (P＜005). Compared with the control group, the levels of COX2, CA199, CEA and VEGF in the two groups were significantly lower than those in the control group (P＜005). Conclusion Huaier granule combined with chemotherapy in the treatment of breast cancer patients with clinical efficacy, can reduce serum levels of COX2, CA199, CEA and VEGF, reduce the incidence of adverse reactions during chemotherapy.