Objective To observe the therapeutic effect and mechanism of Sanzi Yangqin Decoction （Three-Seed Filial Devo- tion Decoction） combined with hormone on mild to moderate asthma.Methods Sixty cases of asthma were randomized into treatment group and control group

with 30in each.The control group was inhaled Budesonide and Formoterol Fumarate Pow- der for Inhalation twice daily

and Sanzi Yangqin Decoction was added in the treatment group three times daily.The treatment course lasted for 12weeks.The disease control situation

grading quantitative score of TCM symptom

lung function and leu- kotriene E4 （LTE4） were observed before and after treatment.Results The disease control rate in the control group and treatment group was 86.7%and 100%respectively

with significant difference between groups （P<0.05） .One second forced expiratory volume （FEV 1） and FEV 1 % predicted increased significantly in both groups after treatment （P<0.05）

especially in the treatment group （P<0.05） .The grading quantitative scores of TCM symptoms and levels of LTE4were significantly decreased in both groups after treatment （P<0.05）

especially in the treatment group （P<0.05） .Conclusion Sanzi Yangqin Decoction combined with Budesonide and Formoterol Fumarate Powder for Inhalation is more effective for mild to moderate asthma than simply using Budesonide and Formoterol Fumarate Powder for Inhalation.The reduction of LTE4may be one of the possible mechanisms of treating asthma.