Background <p>Oral mucositis (OM), as a common adverse effect in patients with chemotherapies, affects the convalescent quality of life. Currently, an increasing number of mouthwashes have been used to improve the incidence of OM in patients undergoing with radiotherapy and chemotherapy. Most studies are comparisons of two arms or three groups, resulting in the lack of direct comparative trial evidence for all care fluids.Therefore, it is not clear which mouthwash is better for preventing the occurrence of OM in patients. This study compares the preventive effects of13 mouthwashes currently used to treat OM in different countries.</p> Methods <p>A computerized search was performed for randomized controlled trials on the use of mouthwash to prevent OM published in databases, such as PubMed, Embase, Web of Science, The Cochrane Library, and China National Knowledge Infrastructure until April 2023. Two investigators used the Cochrane manual to perform a bias risk assessment of the included RCTs and RevMan5.3 to plot the risk bias. Then, a network meta-analysis of the obtained data was performed using Stata 16.2 software.</p> Results <p>A total of 36 randomized controlled trials were included. In the network meta-analysis, the effect of 13 mouthwashes to prevent the occurrence of OM were ranked according to the size of the surface under the cumulative ranking (SUCRA) probability curve value, from best to worst were: aloe vera juice, Chinese herbal medicine, Bing Peng San, honey, <i>Lactobacterium shorti</i>, chamomile, riboflavin, rehabilitation solution, benzydamine, turmeric, aluminum sulfide, povidone-iodine, and chlorhexidine.</p> Conclusion <p>According to the SUCRA ranking results, aloe juice can better prevent OM in other chemoradiotherapy patients than other oral mouthwashes. However, this conclusion still needs to be further verified by randomized controlled trials with a larger sample.</p> Clinical trial number <p>Not applicable.</p>