A Systematic Review of the Effect of Licorice on Head and Neck Chemotherapy- and Radiotherapy-Induced Mucositis

Head and neck cancers are among the most common cancers in the world. The main treatments for these cancers are radiotherapy and chemotherapy, which will cause many side effects, the most important of that is called mucositis. This study was aimed to evaluate the effect of licorice on oral mucositis. The research question was designed according to the Patient/Population, Intervention, Comparison, and Outcomes (PICO) framework, and data were obtained from PubMed, Scopus, Embase, Google Scholar, Science Direct, Springer, Web of Science, Cochrane Science Direct, and ProQuest databases. The search strategies, inclusion and exclusion criteria, validation of selected studies, extraction of the results of each study, impartial interpretation of results, summarizing, discussion, and conclusion of the results were also determined. In the initial search based on the search line and limitations, 143 articles were obtained, 85 of which were excluded because they were irrelevant and their full text was not available. The, 42 articles were excluded because they did not have enough information and were duplicates or reviews. Finally, 16 articles remained, from which nine articles examined the effect of licorice on mucositis. Licorice and its compounds are effective in reducing the duration and severity of chemotherapy- and radiotherapy-induced pain and inflammation. Further, its topical or systemic application can alter its efficacy.