To compare the antiemetic combination of palonosetron, dexamethasone, and aprepitant (PDA) with antiemetic combination of palonosetron and dexamethasone (PD) in nasopharyngeal carcinoma patients receiving docetaxel, cisplatin, and 5-FU based chemotherapy.

Eligible patients will be randomized to receive different antiemetic regimens . In the experimental group,patients will receive aprepitant, palonosetron and dexamethasone .In the other group,patients will accept the same dose of palonosetron and dexamethasone. During the treatment, any grade of nausea and vomiting should be recorded in order to evaluate the complete response rate of CINV,nausea patients will be measured by a visual analogue scale (VAS) ,other adverse events should be recorded as well.

Inclusion Criteria:

1. 18 years of age or older
2. Histologically or cytologically confirmed nasopharyngeal carcinoma
3. Accept chemotherapy for the first time
4. Patients who will receive chemotherapy (docetaxel 60 mg/m2 intravenously (IV), cisplatin 60 mg/m2 IV, and 5-FU (5-Fluorouracil) 600 mg/m2 IV)
5. Written informed consent

Exclusion Criteria:

1. regnant or breast-feeding
2. Uncontrolled psychosis history
3. Inability or unwillingness to understand or cooperate with study procedures
4. Central nervous system tumors primary or secondary
5. Concurrent abdominal radiotherapy
6. History of uncontrolled diabetes mellitus
7. Patients of prostatic hyperplasia ，paralytic ileus，narrow feet glaucoma.
8. Known cardiac arrhythmia, uncontrolled congestive heart failure ,or acute myocardial infarction with the previous six month
9. Pre-existing nausea or vomiting
10. Inadequate hematological function and abnormal liver and renal function.
11. History of sensitivity to olanzapine
12. Concurrent application of quinolone antibiotic therapy
13. Treatment with another antipsychotic agent such as risperidone,quetiapine, clozapine,phenothiazine,or butyrophenone for 30 days prior to or during the chemotherapy.
14. Cytochrome P450 3A4 substrates within 7 days (terfenadine, cisapride, astemizole, pimozide)
15. Concurrent application of systemic corticosteroids
16. Active infection or gastrointestinal dysfunction