Objective: To investigate the prevention effect of Zengye Jiedu granule on radiation-induced pulmonary injury. Method: Sixty patients with lung cancer or esophagus cancer were divided into two groups

30 cases were treated only by the radiotherapy (control group)

another 30 cases were treated by radiotherapy and'Zengye Jiedu granule’ (treatment group). Radiation-induced pulmonary injury was observed. Result: The total incidence rates of acute radiation pneumonitis in the treatment group and the control group were 26.67% and 33.33% respectively. Grade 3 or 4 acute radiation pneumonitis occurred in 6.67% of patients treated with Zengyejiedu granule

and 26.67% in the control group. The average onset time of acute radiation pneumonitis occurred was 31days and 37 days respectively. Conclusion: Zengye Jiedu granule is effective in preventing the occurrence of Grade 3 or 4 acute radiation pneumonitis and delaying the occurrence of radiation-induced pulmonary injury. It is proved that Zengye Jiedu granule may elevate the quality of life and ensure successful radiotherapy.