The purpose of this study is to evaluate whether dietary nitrate supplementation could improve the plasma nitrate levels for nasopharyngeal carcinoma patients receiving concurrent chemo-radiation therapy.

Twenty patients diagnosed as nasopharyngeal carcinoma will be recruited. A 70 ml beetroot juice containing 0.45g nitrate or placebo will be provided to the patients for 7 days at the end of the radiotherapy . The plasma nitrate levels will be determined before radiotherapy, before intervention and after intervention.

Inclusion Criteria:

• Patients with newly diagnosed stages III-IVb (UICC 2002) nasopharyngeal carcinomas, will be recruited.

Exclusion Criteria:

• Patients with local invasion or metastatic foci in salivary glands, detected by MRI and PET-CT prior to treatment, were excluded, as were patients suffering from diseases, such as Sjogren's syndrome, or with a history of surgery to major salivary glands, or prior head and neck radiotherapy.