Objective:To observe the effect of Kechuanning on Th cytokine expression in pediatric virus-induced asthma.Methods:120 cases of pediatric virus-induced asthma were randomly divided into Kechuanning group(treatment group,n =60,treated with Kechuanning) and Western medicine group(control group,n=60,treated with virazole).The change of Th1 cytokine IL-12 and Th2 cytokine IL-4 in blood serum were detected and analyzed.Results:Kechuanning could increase IL-12 but decrease IL-4 level in the patient's blood,therefore regulate Th cell subset,and the effect was more obvious than in control group.Conclusion:The mechanism of Kechuanning in curing pediatrics asthma induced by virus was related with increasing IL-12 and decreasing IL-4 level.