Olanzapine is an atypical antipsychotic that has shown efficacy for the treatment of nausea, anxiety, and insomnia. This study was conducted to evaluate the efficacy of olanzapine (5 mg) combined with 5-HT3 receptor antagonists and dexamethasone for the prevention of chemotherapy-induced nausea and vomiting (CINV) in lung patients receiving cisplatin-based (25 mg/m2 d1-3) highly emetogenic chemotherapy (HEC).Olanzapine (5 mg) was administered a day prior to cisplatin administration and continued on days 1 to 5. We evaluated complete response (CR) rate and rates of no nausea and no vomiting in 3 periods. In addition, Self-Rating Anxiety Scale (SAS), Self-rating Depression Scale (SDS), and The Functional Living Index-Emesis (FLIE) questionnaire were also assessed.A total of 40 lung cancer patients were included. CR for acute, delayed, and over all phases were 82.5%, 75.0%, and 70.0%, respectively. The rate of no nausea in the acute phase was 70.0% and 62.5% in delayed phase. The rate of no vomiting in the acute phase was 85.0%, and 77.5% in delayed phase. The rate of no nausea and no vomiting in the overall phase were 57.5% and 75.0%, respectively. The median SAS and SDS score were 37.9 and 41.6 in pre-chemotherapy, respectively. Up to day 6 after chemotherapy treatment, the median SAS and SDS score were 36.9 and 42.0, respectively. The median FLIE score was 111.7. The main side effects were grade 1 somnolence (35.0%) and mild constipation (52.5%).Around 5 mg olanzapine may be used as a potential, safe, and cost-beneficial alternative to prevent nausea and vomiting for HEC, particular for multiday chemotherapy regimen.