Radiodermatitis is a common side effect of radiotherapy, but currently there is no standard treatment for its prevention. This study aimed to observe the effect of topical application of a paste based on traditional Chinese medicine, Jiawei Simiao Yongan Gao, on radiodermatitis caused by radiotherapy for patients with head and neck cancer.This was a retrospective cohort study of 40 patients with head and neck cancer evaluated during their radiotherapy. Of these, 20 patients were treated with Jiawei Simiao Yongan Gao on the irradiated skin from the beginning of radiotherapy (JSY group). The other 20 patients were given standard nursing (standard group). Acute skin reactions were classified according to the radiation-induced skin reaction assessment scale (RISRAS) and American radiation therapy oncology group (RTOG) acute toxicity grading criteria every 2 weeks, and adverse effects were recorded until the end of the radiotherapy.The two groups showed differences in severity of radiodermatitis. At 0 to 30 Gy, the skin reactions were similar in the two groups, while above 40 Gy the skin reactions were significantly lower grade in the JSY group (P < .05). At 0 to 20 Gy, there was no statistical significance (P > .05); but above 30 Gy they were lower in the JSY group (P < .05).Jiawei Simiao Yongan Gao effectively alleviated acute radiodermatitis caused by radiotherapy of head and neck cancer patients compared with standard nursing.