Objective To explore the effect of Xaoqinglong decoction on the expression of NGF on the lung and thymus in asthmatic guinea pigs.Methods The change of NGF expression were observed with immunohistochemistry and RT-PCR in the 1ung and thymus of all guinea pigs.Results The expression of NGF in the lung and thymus of asthmatic guinea pigs in asthmatic group was much higher than that in control group and the expression of NGF in Xiaoqinglong group was much lower than that in asthmatic group.Conclusion The NGF is possible to participate in the pathogenesis of the bronchial asthma,and the treating m...