ObjectiveTo analyze the application value of 5-HT3 receptor antagonist in breast cancer patients with CEF chemotherapy.Methods70 breast cancer patients received CEF chemotherapy scheme(including adjuvant chemotherapy and palliative chemotherapy)in our hospital from February 2014 to November 2016 were selected as research object,and they were divided into two groups by random number table,35 cases in each.Two groups were given breast cancer CEF chemotherapy.Observation group was given intravenous drip of Ondansetron combined with Dexamethasone before chemotherapy for 30 min and after chemotherapy,q8h.Control group was given purely CEF chemotherapy,and was given intravenous drip of Ondansetron combined with Dexamethasone before chemotherapy for 30 min,and after chemotherapy they were not given any drug intervention.The incidence of nausea and vomiting,performance status scores before and after treatment of two groups were compared.ResultsThere was no statistical difference in the total incidence of nausea and vomiting between two groups(P>0.05);before treatment,the performance scores of two groups were(88±10),(87±9)points respectively,there was no statistical significance between the two groups(P>0.05);after treatment,the performance score of observation group was(79±10)points,which was significantly higher than (75±5)points of control group (P<0.05).Conclusion5-HT3 receptor antagonist can effectively decrease adverse reactions of nausea and vomiting in breast cancer patients with CEF chemotherapy.According to half-life period of 5-HT3 receptorantagonist,increasing times of administration can facilitate to increase patients′treatment compliance and improve treatment satisfaction,which is worthy of clinical promotion.