Abstract: OBJECTIVE To observe the effects of Xiefei decoction on the pathomor-phism changes of lung tissue and the expression of Fas protein and FasL protein in lung tissue of pulmonary fibrosis rats induced by bleomycin. METHODS Eighty-four SPF SD rats were randomly divided into blank control group, bleomycin model group, low, middle and high-dose Xiefei decoction treatment groups and prednisone group, 14 rats in each group. Except for the blank control group, the remaining groups used tracheal instillation of bleomycin to prepare pulmonary fibrosis rat models. In the blank control group, an equal amount of saline was instilled into the trachea. After 24 h of modeling, Xiefei decoction was administered by gavage of Xiefei decoction(10, 20, 40 g·kg^-1·d^-1) in the low, medium and high dose groups, and by prednisone acetate in the prednisone acetate group(1.8 mg·kg^-1·d^-1), the blank control group and the bleomycin model control group were gavaged with equal volume of normal saline, and the animals were sacrificed on the 29th day. To observe the pathomorphism changes of lung tissue with HE, check the contents of ICAM-1 and CTGF in serum with ELISA, Fas gene, FasL gene in lung tissue was assessed by RT-PCR, and Fas protein, FasL protein in lung tissue was assessed by Western blotting. RESULTS Compared with the bleomycin model group, the contents of ICAM-1, CTGF and the gene expression of Fas, FasL were decreased significantly in all groups of Xiefei decoction(P<0.05 or P<0.01). Meantime, the protein expression of Fas, FasL were also decreased in middle-dose, high-dose group of Xiefei decoction(P<0.05 or P<0.01). CONCLUSION Pulmonary fibrosis is improved significantly after the Xiefei decoction treated, the levels of ICAM-1, CTGF and the expressions of Fas/FasL are both decreased. These data shows that Xiefei decoction ameliorate the pulmonary fibrosis induced by bleomycin and it is related to Fas/FasL apoptotic pathways.