Abstract：Objective：To observe the intervention effect of modified YangYin Jiedu tang on rash of yin deficiency with internal heat type induced by gefitinib. Methods： A total of 80 patients with rash of yin deficiency with internal heat type were selected and randomly divided into the control group and the treatment group，with 40 cases in each group. The control group was treated with symptomatic western medicine according to the grade of rash，and the treatment group was treated with modified YangYin Jiedu tang based on the treatment of the control group. Both groups were treated for two weeks. The clinical effects， the time of first disappearance of rash， the grade of rash and the scores of Dermatology Life Quality Index(DLQI) in the two groups were compared. Results：After treatment，the grade of rash in the treatment group was better than that in the control group(P＜0.05). The total effective rate was 92.5% in the treatment group，higher than that of 77.5% in the control group(P＜0.05). After treatment，the scores of DLQI in both groups were increased when compared with those before treatment(P＜0.05)，and the score of DLQI in the treatment group was higher than that in the control group(P＜0.05). The time of first disappearance of rash in the treatment group was(5.62±0.57) days，which was shorter than that of(8.73± 0.65) days in the control group(P＜0.05). Conclusion：Modified YangYin Jiedu tang can effectively improve the clinical symptoms of patients with rash of yin deficiency with internal heat type induced by gefitinib，and enhance their quality of life.