<![CDATA[Highlights: Pre-chemotherapy oral ondansetron significantly reduced the incidence of nausea and vomiting in patients with head and neck malignancies. Patients receiving oral ondansetron before chemotherapy had significantly lower nausea and vomiting scores across chemotherapy cycle 1-3 compared with those who did not receive ondansetron. Abstract Introduction: Head and neck malignancies are the most common type of cancer found in clinical applications and are a global health problem. Surgical procedures, chemotherapy, radiotherapy, or a combination are the treatment modalities for head and neck cancer. Chemotherapy is one of the treatment options for head and neck cancer. The most common side effects complained of by patients after chemotherapy are nausea and vomiting. Methods: This was experimental research with a pretest-post-test control-group design using a prospective cohort. Evaluation using nausea and vomiting scores was performed 3 times post-chemotherapy at 24 hours (acute phase), from cycle 1 to cycle 3. Analysis using the Mann-Whitney test and Friedman test. The study was conducted by collecting primary data through interviews. Results: The results of the comparative analysis of the incidence of nausea and vomiting with and without pre-chemotherapy ondansetron administration in cycle 1, 2, 3 were p<0.05. The results of the analysis of changes in the incidence of nausea and vomiting in the group with pre-chemotherapy ondansetron administration in cycles 1, 2, and 3 were p=0.05. Changes in the incidence of nausea and vomiting in the group without pre-chemotherapy ondansetron administration were p<0.05. Conclusion: There was a significant difference between subjects who received oral ondansetron pre-chemotherapy for 7 days compared to those who did not receive oral ondansetron pre-chemotherapy in head and neck cancer patients regarding the incidence of post-chemotherapy nausea and vomiting.]]>
