Inclusion Criteria:  Pathology confirmed squamous cell carcinoma. The primary sites included nasopharynx, mouth, oropharynx, hypopharynx, larynx, nasal cavity and paranasal sinuses Aged 18 to 70 years old Stage III-IVB diseases Eastern Cooperative Oncology Group Performance Status 0-1 Normally functioning of liver, kidney, bone marrow Concurrent chemoradiotherapy is recommended after multi-disciplinary team discussion; Must be able to swallow tablets At least 12 weeks lifetime was expected; Fertile male or female patients volunteered to use effective contraception within 90 days of the study period and at the end of study.  Exclusion Criteria:  Other medical histories of malignancy apart from non-melanoma skin cancer, cervical carcinoma in situ, and early-stage cured prostate cancer Nausea and emesis occurred 24 hours before the start of CCRT Any medicine which affected metabolism through drug-metabolising enzymes CPY3A4 and CYP2D6 except for nighttime sedatives Mental and severe cognitive impairment Perinatal women or rejection of taking contraception during treatment Drug and/or alcohol addiction Symptomatic brain metastasis Gastrointestinal obstruction Hypocalcemia or any other conditions that could provoke emesis Treatment with another antipsychotic agent for 30 days before or during protocol therapy Concurrent chest or abdominal radiotherapy Concurrent use of corticosteroid or amifostine or quinolone antibiotic therapy Known hypersensitivity to olanzapine Known uncontrolled cardiac arrhythmia, uncontrolled congestive heart failure, or acute myocardial infarction within the previous 6 months Medical history of diabetic ketoacidosis or uncontrolled diabetes mellitus, prostate enlargement, narrow angle glaucoma