To explore the efficacy and safety of adding olanzapine (5 mg or 10 mg) to 5-hydroxytryptamine type 3 receptor antagonists (5-HT3 RA), neurokinin-1 receptor antagonists (NK1 RA), and dexamethasone for nausea and vomiting in patients with nasopharyngeal carcinoma (NPC) receiving cisplatin-based concurrent chemoradiotherapy. The gene discussed is TACR1; the disease is nasopharyngeal carcinoma.