Objectives: Mucositis, which usually occurs with chemotherapy and radiotherapy, causes pain, loss of taste, difficulty in eating foods, and subsequently weight loss. Reviewing literature reveals that using ice chips can significantly prevent mucositis during chemotherapy, and the aim of this study is to see the impact of ice chips on mucositis during radiotherapy. Design: 40 patients were divided randomly into 2 groups. Control group patients merely receive ordinary oral care, which consists of soft toothbrush, non-erosive toothpaste, and dental floss. Intervention group patients use ice cubes 5 minutes before and after each radiotherapy session, in addition to ordinary oral care. Setting and conduct: Patients will be examined on 1st, 7th, and 14th day of study, and mucositis will be assessed by both dentists and patients, using questionnaires. Comparison of improvement percentage between two groups will be performed by chi square test, and comparison of mucositis severity between two groups will be performed by kruskal-wallis test. In order to determine the relationship between mucositis and variables such as cancer type, radiation power, intervention type etc logistic regression will be used. Inclusion criteria: patients undergoing radiotherapy in mouth or part of head and neck; at least one salivary gland must be in the field of radiation (more than 3000 Gy). Exclusion criteria: existence of mucositis before starting radiotherapy; any systemic disease or medicine consumption affecting oral cavity. Intervention: patients of this group hold the ice cubes in their mouths for 5 minutes before and after each radiotherapy session, everyday. Main outcome measures (variables): 1.physician judged mucositis: clinical examination by the dentists and filling standardized physician judged mucositis grading forms on 1st, 7th, and 14th days of the study. 2. patient-judged mucositis: interview with patient and filling standardized patient-judged mucositis grading forms on 1st, 7th, and 14th days.