Abstract：Objective：To observe the clinical effect of modified San'ao tang for upper airway cough syndrome(UACS) of wind- phlegm type and its effect on levels of Th1/Th2 cytokines in peripheral blood. Methods：A total of 92 cases of UACS patients of wind- phlegm type were selected and divided into the treatment group and the control group according to the random number table method，with 46 cases in each group. After experiment，three cases of patients were lost，and finally with 45 cases in the control group and 44 in the treatment group. The treatment group was treated with modified San'ao tang，and the control group was treated with loratadine tablets and montelukast sodium tablets. Both groups were treated for two weeks. Before and after treatment， the changes in Chinese medicine syndrome scores， quality of life of Leicester Cough Questionnaire(LCQ) scores，and peripheral vein blood including interferon-γ(IFN-γ) and interleukin-4(IL-4) in the two groups were observed. After treatment， the incidences of adverse reactions and clinical effects in the two groups were compared. Results： After treatment， the scores of cough， expectoration， throat itching， postnasal drip and pharyngeal signs in the two groups were decreased when compared with those before treatment(P＜0.05)，and the scores of cough， expectoration and pharyngeal signs in the treatment group were lower than those in the control group， differences being significant(P＜0.05). The total effective rate of clinical effect was 90.91% in the treatment group and 77.78% in the control group，the difference being significant(P＜0.05). After treatment，the LCQ scores in the two groups were increased when compared with those before treatment， and the score in the treatment group was higher than that in the control group， differences being significant(P＜0.05). After treatment， the levels of IFN- γ in peripheral blood in the two groups were increased when compared with those before treatment(P＜0.05)，and the IL-4 levels were decreased(P＜0.05)；the IFN-γ level in the treatment group was higher than that in the control group， and the IL- 4 level was lower， differences being significant(P＜0.05). During treatment and after treatment，there were stable vital signs in the the groups and no abnormality in blood routine，urine routine and liver and kidney function. The incidence of adverse reactions was 0 in the treatment group and 17.78% in the control group，the difference being significant(P＜0.05). Conclusion：Modified San'ao tang for UACS of wind-phlegm type has a significant curative effect and can regulate levels of cytokines and improve quality of life，with higher medication safety.