Inpatients or outpatients diagnosed with head and neck cancer who met the inclusion and exclusion criteria were referred to the co-investigator(Dr. Chih-Jen Huang and Dr. Hui-Ching Wang), who then personally explained to each participant, the purpose and conduct of the study, so that they all understood their rights and interests before giving a written consent.

The study design was a randomized controlled trial and a longitudinal study with structured questionnaires (17-question basic information questionnaire、 The World Health Organization scale, WHO、NCI-CTCAE V5.0、Brief Pain Inventory-Taiwan、oral frailty checklist、European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-head & neck). The participants were randomly assigned to the experimental group (gargling with hydrogen water) and the control group (gargling with boiled water) by block randomization through a questionnaire administered by the investigator. At the end of cancer treatment (chemotherapy, radiotherapy, or Chemoradiotherapy), a hydrogen water gargle (dissolved for 12 hours or longer) or boiled water gargle was administered by the investigator or a researcher every Monday through Friday. The changes in six scales described above were tracked in the experimental and control groups on days 1 (T1), 3 (T2), 7 (T3), and 14 (T4) after the end of treatment. The data from these scales were entered into a computer and analyzed using statistical software, and the overall data are presented to demonstrate the efficacy of hydrogen water.

Inclusion Criteria:

1. pathological diagnosed with head and neck cancer
2. adults over the age of 20
3. have normal cognition
4. can use Mandarin or Taiwanese to communicate
5. received radiation therapy or combined chemotherapy

Exclusion Criteria:

1. Eastern Cooperative Oncology Group (ECOG) performance status 2, 3 and 4
2. received oral cancer surgery within two months