Objective:To observe effects of astragalus injection on immune functions of sub-populations of T lymphocyte and natural killer cells（NK-cell） in patients of bronchial asthma with acute exacerbations.Method: Seventy two patients with acute bronchial asthma were divided randomly into two groups

namely control group（conventional therapy） and astragalus group（conventional therapy+ astragalus injection）.The effects of treatment were observed;the changes in T lymphocyte and CD3+

CD4+

CD8+

CD4+/CD8+ in peripheral blood were detected.Result: After treatment of 14 days

the clinical control rate and the total efficiency of the astragalus group（68.6%

97.1%） were significantly higher than that of the control group（43.2%

78.4%）（P<0.05）.Before treatment

CD3+

CD4+

CD4+/CD8+ and NK in the astragalus group and the control group were significantly lower than that of the healthy group（P<0.01）.After treatment

CD3+

CD4+

CD4+/CD8+ and NK in the Astragalus group [（61.47±5.31）%

（39.60±5.36）%

（1.61±0.41）

（31.79±4.11）%] were significantly higher than that before treatment（P<0.01） and the control group [（56.02±4.51）%

（33.30±5.22）%

（1.27±0.52）

（29.60±4.41）%]（P<0.01 or P<0.05）.Adverse reaction rate in the astragalus group was significantly lower than that in control group（P<0.05）.Conclusion: On the basis of routine treatment

combined with astragalus injection can improve the effects for the treatment of acute bronchial asthma

while it is able to relieve the harmful reactions induced by using steroids.The mechanism may be related to the improvement of immune function of T lymphocyte and NK-cells.