Abstract: OBJECTIVE To evaluate the amelioration of alcohol extracts from the pinecone of Pinus yunnanensis Franch. on pulmonary fibrosis in mice. METHODS The pulmonary fibrosis model was prepared by intratracheal injection of bleomycin. The corresponding drugs were given on the second day after modeling. On the 28th day of the experiment, the eyeball blood was taken to determine peripheral blood counts and the thymus, spleen and lung were harvested to calculate the immune organ index and lung index, respectively. Then the lung tissues were stained by HE and Masson to evaluate the pulmonary alveolitis and pulmonary fibrosis, respectively. The immunohistochemistry method was applied to determine the protein expression of STAT3. Finally the ELISA method was used to detect the serum levels of IFN-γ, TNF-α, HYP and the content of TGF-β in lung tissues homogenate. RESULTS Compared with model group, the contents of TNF-α in serum and TGF-β in lung tissues homogenate from Pinus yunnanensis Franch. high dose group decreased significantly(P<0.05 or P<0.01), the positive expression granule of STAT3 in lung tissue epithelial cells decreased significantly and the mean density descended (P<0.01). The serum IFN-γ content of the Pinus yunnanensis Franch. high and middle dose groups was significantly increased(P<0.01 or P<0.05), and the content of HYP in the Pinus yunnanensis Franch. groups was significantly decreased(P<0.01). Histopathological results showed that compared with model group, the pulmonary alveolar score and pulmonary fibrosis score in Pinus yunnanensis Franch. high dose group were decreased significantly(P<0.01). CONCLUSION The alcohol extract from pinecone of Pinus yunnanensis Franch. has an ameliorative effect on bleomycin-induced pulmonary fibrosis in mice, which may be related to reduction of collagen deposition and inflammation.