['nasopharyngeal neoplasms', 'stomatitis']
['oral ulcer gargle (forrad®)', 'quadruple mixture, composed of dexamethasone, gentamicin, vitamin b12, and procaine']

        Inclusion Criteria:

          1. Pathologically confirmed and previously untreated nasopharyngeal carcinoma.

          2. Age ≥ 18 years and ≤ 65 years.

          3. Karnofsky performance status (KPS) score ≥ 70.

          4. Planned to receive radiotherapy alone or concurrent chemoradiotherapy, with
             intensity-modulated radiation therapy (IMRT).

          5. Adequate bone marrow function: while blood cell >= 3,000/μL, absolute neutrophil count
             >= 1,500/μL, hemoglobin >= 100g/L, platelet >= 75,000/μL.

          6. Life expectancy of >= 3 months.

        Exclusion Criteria:

          1. Known allergic reaction to any component of Oral Ulcer Gargle (FORRAD®) or quadruple
             mixture, which is composed of dexamethasone, gentamicin, vitamin B12, and procaine, or
             severe allergic constitution.

          2. Other conditions that the investigators consider as inappropriate for enrolling into
             this study.
      