Objective To explore the mechanism of Xiefei Pingchua nling （Formula for clearing the lung to stop asthma） and its decomposed formulas in blocking th e endotoxemia causing the pulmonary injury of the Lung and Large Intestine Inter iorly-exteriorly Related Model rats.Methods Seventy S D rats were randomized i nto blank group

model group

ligation-removed group

Xiefei Pingchuanling gro u p

decomposed formula San’ao

Santong

and Sanhuo groups

with 10 in each.The L ung and Large Intestine Interiorly-exteriorly Related models were made by incom plete ligation of the rectum in vitro.Seventy-two hours after modeling the rats of mode l group were killed.All other medicinal intervention groups were treated with i ntragastric feeding 1ml/100g body weight of San’ao

Santong

and Sanhuo decoctions

and Xiefei Pingchuanling respectively everyday after ligation removed.The lig ation-removed group and blank group were given the same volume normal saline.T hree days later the changes of phospholipid and albumin in pulmonar y alveoli lavage fluid were observed.Results The level of albumin in pulmonar y alveoli lavage fluid of the model group was significantly increased （P<0.01）

while the level of phospholipid decreased （P<0.01）.The level of albumin of the ligation-removed group

Xiefei Pingchuanling group

and decomposed formula gro u ps was decreased

while the level of phospholipid increased

there existed a sig nificant difference in comparing with that of the model group （P<0.01）.Co nclusion Xiefei Pingchuanling and its decomposed formulas could effectively decrease the albumin in pulmonary alveoli lavage fluid of model rats

thus reducing the exhaustio n of phospholipid to block endotoxemia causing the injury of lung tissues and functions.