Abstract: OBJECTIVE To investigate the intervention effect of effective strains of endophytic and Glycyrrhizae Radix et Rhizome(Glycyrrhiza) on rats with turbid phlegm obstructing in the lung, and filtrate effective strains.METHODS One hundred and thirty Wistar rats were randomly divided into normal group, model group, positive group, decoction of Glycyrrhiza group and different effective strains of endophytic of Glycyrrhiza groups. The rat model of phlegm blocking in the lung was established by inhaleing SO2 and clod wind for 10 d in model and intervention groups. Since sixth day, drug intervention group were given corresponding drugs for 7 d. The expectorant effects were studied by observing the changes of rats' general activities, detection of lung function in conscious non-invasive state, tracheal excretion of phenol red and pathological of lung tissues. In addition,the contents of IL^-17 and IL-23 were detected.RESULTS Compared with the model group, the index of lung function tests of JTZB005, JTZB006, JTZB058 and JTZB063 were rised significiantly (P<0.05). Compared with the decoction of Glycyrrhiza group, the effects of JTZB005 and JTZB058 were similar. The tracheal excretion of phenol red and the content of IL^-17 and IL-23 of rats were decreased significiantly(P<0.05), and their effects were similar with decoction of Glycyrrhiza group.CONCLUSION By filtrating, 4 effective strains of endophytic of Glycyrrhiza have effects in turbid phlegm obstructing, and the physiological activity of them are similar with their host Glycyrrhiza.