Objective To observe the effect of tropisetron and tranquilizer on preventing nausea and vomiting induced by breast cancer chemotherapy,in comparison with using only tropisetron.Methods 78 cases of breast cancer patients undergoing chemotherapy were randomly divided into the observation group (40 cases) and the control group (38 cases).The observation group used the method of antiemetic intravenous tropisetron,while the control group adopted intravenous drip of tropisetron combined with intramuscular injection of chlorpromazine.The incidence of nausea and vomiting of two groups was observed.Results The incidence of nausea and vomiting of the observation group was higher than that of the control group.The incidence of adverse reaction showed no obvious difference between two groups.Conclusions Intravenous injection of tropisetron combined with intramuscular injection of chlorpromazine can reduce nausea and vomiting caused by chemotherapy of breast cancer,so this method is worthy of popularization.