Objective: To evaluate the efficacy of compound Dixiong Decoction (地芎汤, a Chinese herbal decoction) on early prevention of radiation pneumonitis. Methods: Forty-six patients with non-small cell lung cancer who were planning to receive radiotherapy were randomly assigned to the treatment group treated with the compound Dixiong Decoction and the control group treated with a commonly used herbal decoction which has the effects of supplementing qi and nourishing yin, clearing heat and detoxifying at the time of radiotherapy. Primary measure was the incidence of radiation pneumonitis after radiotherapy. Secondary outcomes included Watters clinical radiographic physiologic (CRP) dyspnea score, the Radiation Therapy Oncology Group (RTOG) grading score, Karnofsky Performance Status (KPS) score, and the application of corticosteroids. Results: The incidence of radiation pneumonitis in the treatment group was 10.0%, while that in the control group was 26.3% (P=0.0032). The Watters CRP dyspnea score and RTOG grading score in the treatment group were significantly lower than those in the control group (P<0.05). The KPS score in the treatment group was significantly higher than that in the control group (P<0.01). The dosage of corticosteroids was smaller with a shorter duration of therapy in the treatment group than that in the control group. Conclusion: The early application of the Chinese herbal decoction compound Dixiong Decoction can decrease the incidence of radiation pneumonitis, reduce the injury of the lung, and improve the life quality of the patients. Objective: To evaluate the efficacy of compound Dixiong Decoction on early prevention of radiation pneumonitis. Methods: Forty-six patients with non-small cell lung cancer who were planning to receive radiotherapy were randomly assigned to the treatment group treated with the compound Dixiong Decoction and the control group treated with a commonly used herbal decoction which has the effects of supplementing qi and nourishing yin, clearing heat and detoxifying at the time of radiotherapy. Primary measure was the incidence of radiation pneumonitis after radiotherapy. Secondary outcomes included Watters clinical radiographic physiologic (CRP) dyspnea score, the Radiation Therapy Oncology Group (RTOG) grading score, Karnofsky Performance Status (KPS) score, and the application of corticosteroids. Results: The incidence of radiation pneumonitis in the treatment group was 10.0% while while that in the control group was 26.3% (P = 0.0032). The Watters CRP dysp The dosage of nea score and RTOG grading score in the treatment group were significantly lower than those in the control group (P <0.05). The KPS score in the treatment group was significantly higher than that in the control group (P <0.01). The dosage of corticosteroids was smaller with shorter duration of therapy in the treatment group than that in the control group. Conclusion: The early application of the Chinese herbal decoction compound Dixiong Decoction can reduce the incidence of radiation pneumonitis, reduce the injury of the lung, and improve the life quality of the patients.