AbstractIntroduction:This is a prospective, open-label, parallel-group, randomized controlled trial that evaluates the effectiveness and safety of adjuvant application of Jaungo (JUG) for radiation-induced dermatitis (RD) in breast cancer patients undergoing radiation therapy, in comparison with general supportive care (GSC).Methods/design:Eighty female patients, who have been diagnosed with unilateral breast cancer, will be allocated to either the JUG or GSC group with an allocation ratio of 1:1 after breast conservation surgery, in the Kyung Hee University Korean Medicine Hospital, Seoul, Republic of Korea. Both the groups will be subjected to GSC, but only the JUG group participants will apply adjuvant JUG ointment on the irradiated skin for 6 weeks, twice a day. The primary outcome of this study is the assessment of incidence rate of RD using the Radiation Therapy Oncology Group (RTOG) for toxicity gradation of 2 or more. Maximum pain level, quality of life, adverse reactions, and pharmacoeconomic evaluations will also be included.Discussion:The primary outcome will be statistically compared using the logrank test after estimating the survival curve using the Kaplan–Meier method. Continuous variables will be tested using independent t test or Mann–Whitney U test. The adverse events will be evaluated with Chi-square or Fisher exact test. All the data will be analyzed at a significance level of 0.05 (two-sided) with R software (The R Foundation).Trial registration:CRIS (Clinical Research Information Service), KCT0003506, 14 February 2019.