Background: Few studies have attempted to evaluate the use of antiemetic therapy for chemotherapyinduced nausea and vomiting(CINV) at a national level in China or to assess how treatment regimens adhere to current guidelines. Methods: We searched the China Health Insurance Research Association(CHIRA) Database to identify patients with cancer who were ≥18 years old and received either moderately or highly emetogenic chemotherapy(MEC and HEC, respectively) between 2008 and 2012. Patients’ characteristics as well as usage of specific antiemetic regimens were analyzed using descriptive statistics. Results: Of the 14,548 patients included in the study, 6,477 received HEC while 8,071 were treated with MEC. Approximately 89.9% used antiemetics prophylactically to prevent acute CINV and 71.5% for delayed CINV while 9.0% were prescribed antiemetics as rescue therapy. A significantly lower proportion of patients treated with HEC received prophylactic antiemetic therapy for delayed CINV as compared to those treated with MEC(59.4% vs. 81.3%; P<0.001). The HEC group had a slightly lower proportion of patients using a mixed regimen containing a 5-HT3 antagonist to prevent both acute and delayed CINV than the MEC group(P≤0.012); however, a higher proportion received a mixed regimen containing corticosteroids(P≤0.007). Although more than half of the patients in the HEC group took three antiemetics to prevent acute and delayed CINV, these rates were significantly lower than those of the MEC group(both P<0.001). Finally, analysis of the regimens used revealed that there is over-utilization of drugs within the same class of antiemetic. Conclusions: These findings indicate that more attention is needed for treatment of delayed CINV, in terms of both overall use and the components of a typical treatment regimen. Background: Few studies have attempted to evaluate the use of antiemetic therapy for chemotherapy led nausea and vomiting (CINV) at a national level in China or to assess how treatment regimens adhere to current guidelines. Methods: We searched the China Health Insurance Research Association (CHIRA ) Database to identify patients with cancer who were ≥18 years old and received either moderately or highly emetogenic chemotherapy (MEC and HEC, respectively) between 2008 and 2012. Patients’ characteristics as well as usage of specific antiemetic regimens were analyzed using descriptive statistics. Results: Of the 14,548 patients included in the study, 6,477 received HEC while 8,071 were treated with MEC. Approximately 89.9% used antiemetics prophylactically to prevent acute CINV and 71.5% for delayed CINV while 9.0% were prescribed antiemetics as rescue therapy. A significantly lower proportion of patients treated with HEC received prophylactic antiemetic therapy for delayed CINV as comp The HEC group had a slightly lower proportion of patients using a mixed regimen containing a 5-HT3 antagonist to prevent both acute and delayed CINV than the MEC group (59.4% vs. 81.3%; P <0.001) (P≤0.012); however, a higher proportion of the patients receiving the HEC group took three antiemetics to prevent acute and delayed CINV, these rates were significantly lower than than those of the MEC group (both P <0.001). Finally, analysis of the regimens used revealed that there is over-utilization of drugs within the same class of antiemetic. Conclusions: These findings indicate that more attention is needed for treatment of delayed CINV , in terms of both overall use and the components of a typical treatment regimen.