Objective:Evidence Based Medicine (EBM) is used to do systematic reviews on Shegan Mahuang tang (Ephedra decoction) controlling cough variant asthma (CVA) in children. Method:Data retrieval is done on the websites such as cnki

cqvip

wanfangdata and offline professional magazines. Result:Ninty-four pieces of literatures are attained and 7 pieces accord with the inclusive criteria. Jadad Criteria is adopted to assess every literature's Methodological quality

all of which are low quality ones. 470 cases are obtained. OR=2.99

95% CI of 1.90 to 4.71

test for overall effect:Z=4.71(P<0.000 01). Therefore

the difference is statistically significant. Conclusion:The existed clinical evidences shows

Shegan Mahuang tang is effecitve to control cough variant asthma (CVA) in children. However

randonmized control clinical trials are subsumed by systematic reviews belong to low quality ones

so Shegan Mahuang tang's therapeutic effect need to be further examined by a large scale of high quality of clinical trials.