Objective,2,To observe the clinical efficacy of oral administration of modified Linggui Zhugan Decoction combined with external application of Xiaoshui Recipe in treating lung cancer with pleural effusion.,Methods,2,Sixty-four patients of lung cancer with pleural effusion were randomly divided into the treatment group and control group， 32 cases in each group. The control group was treated with conventional western medicine， and the treatment group was treated with Linggui Zhugan Decoction by oral administration and Xiaoshui Recipe by external application based on the treatment for the control group. The treatment course was 7 days in both groups. The clinical efficacy was observed， the changes of Chinese medical syndrome scores， immune indexes， inflammatory factors and tumor indexes were compared， as well as the puncture and drainage of pleural effusion and the use of diuretics.,Results,2,①During the trial， two cases in the treatment group and two cases in the control group fell off， finally 60 cases completed the trail， among 30 cases in the treatment group and 30 cases in the control group. ②The total effective rates of the treatment group and the control group were 86.7% and 60.0% respectively. The clinical efficacy of the treatment group was better than that of the control group （,P,<,0.05）. ③Compared with those before treatment， the total score of Chinese medical syndrome and the scores of cough， shortness of breath， chest tightness and mental fatigue were decreased in the treatment group after treatment （,P,<,0.05）， while the total score of Chinese medical syndrome and the score of shortness of breath were increased in the control group （,P,<,0.05）. After treatment， the total score of Chinese medical syndrome and the scores of cough， shortness of breath， chest tightness and mental fatigue in the treatment group were lower than those in the control group （,P,<,0.05）. ④Compared with those before treatment， the levels of CD3,+, and CD4,+, in peripheral blood were increased and the levels of interleukin-2 （IL-2）， interleukin-6 （IL-6）， interleukin-8 （IL-8）， malignant tumor specific growth factor （TSGF） and carcinoembryonic antigen （CEA） were decreased in the treatment group （,P,<,0.05）， but there were no statistically significant differences on the immune， tumor and inflammatory factors in the control group after treatment （,P,>,0.05）. After treatment， the levels of CD3,+, and CD4,+, in the treatment group were higher than those in the control group， and the levels of IL-2 and IL-6 in the treatment group were lower than those in the control group （,P,<,0.05）. ⑤The rate of pleural effusion puncture and drainage in the treatment group was lower than that in the control group （,P,<,0.05）， and there was no statistically significant difference in the use of diuretics between the two groups （,P,>,0.05）.,Conclusion,2,Oral administration of modified Linggui Zhugan Decoction combined with external application of Xiaoshui Recipe shows good efficacy in treating lung cancer with pleural effusion， which can effectively reduce pleural effusion and improve the clinical symptoms of patients.