To observe different effects of Maimendong Decotion and Gancao GanjiangDecotionin on pulmonary fibrosis rat in the stage of fibrotic phase.Methods:After 14 days of establishing rat model by intratracheal injection of bleomycin,Maimendong decotion(7.5 g/kg,15 g/kg,30 g/kg) and Gancao Ganjiang decotion(3.75 g/kg,7.5 g/kg,15 g/kg) were given by gavage once a day for 2 week.Meanwhile,the model group and the normal group were administered with distilled water of same quantity.After gavage of decotion for 14 days,the forced vital capacity (FVC),the indexes of lung dynamic compliance(Cdyn),the ratio of FEV 0.4 to forced vital capacity(FEV0.4/FVC%),peak expiratory flow rate (PEF),maximal mid-expiratory flow rate (MMF) and the blood gas changes were recorded,then the organ coefficients were calculated,lung tissue and airway pathologic changes were observed by HE staining.Results:Compared with the model group,the high dose group of Maimendong decotion reduced the lung weight and lung index significantly(P<0.05),and increased Cdyn,FVC and FVC/lung weight significantly(P<0.05).The Cdyn and FVC of high dose group of Gancao Ganjiang decotion were higher than the model group(P<0.05).The intermediate-dose Gancao Ganjiang decotion improved FVC/lung weight (P<0.05) and reduced the rate of FEV0.4/FVC% significantly (P<0.05) compared with the model group.Gancao Ganjiang decoction improved PO2 and SO2 significantly compared to model group(P<0.05).Conclusion:Both Maimendong decotion and Gancao Ganjiang decotion are better for the rat model of bleomycin induced pulmonary fibrosis.The former can reduce the interstitial hyperplasia around the airway in fibrosis area,and the latter protect the structure and function of the alveolar in non-fibrosis area.