Olanzapine and 5-HT3 With or Without Dexamethasone to Prevent CINV

Inclusion Criteria: 1. Patients 18 years of age or older with malignant disease； 2. Life expectancy ≥ 3 months; 3. Scheduled to receive highly emetogenic chemotherapy； 4. Had a European Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2 Exclusion Criteria: 1. There are contraindications to chemotherapy(Absolute number of neutrophils ≤ 1,500/uL, hemoglobin ≤ 90g/L, platelet count ≤ 10000/uL, serum creatinine level ≥ 2.0mg/dl (177 μmol/L), ALT and AST ≥ 2.5 times the upper normal limit, bilirubin ≥ 1.5 times the upper normal limit); 2. History of central nervous system disease (e.g., brain metastases or a seizure disorder); 3. Severe cognitive impairment； 4. Treatment with another antipsychotic agent such as risperidone, quetiapine, clozapine, a phenothiazine, or a butyrophenone within 30 days before enrollment or plans for such treatment during the study period; 5. Concurrent use of pharyngeal or abdominal radiotherapy; 6. Concurrent use of quinolone antibiotics; 7. Concurrent use of Amifostine; 8. Chronic alcoholism; 9. Known hypersensitivity to olanzapine; 10. Know arrhythmia, uncontrolled congestive heart failure or acute myocardial infarction within 6 months; 11. Known uncontrolled diabetes mellitus; 12. Vomiting or retching 24 hours before chemotherapy; 13. Use of anti-emesis drugs 48 hours before chemotherapy; 14. Patients who require medication with dexamethasone for pretreatment.