Abstract: ［Abstract］Objective To investigate the anti-fibrotic effect of Kudancao tablets on bleomycin-induced pulmonary fibrosis in rats . Methods Forty healthy adult SD rats（200±20g）were randomly divided into 4 groups: normal control group（without any treatment），normal saline group（intratracheal instillation of normal saline ），model group（intratracheal instillation of 5mg/kg of Bleomycin）and kudancao tablets group（intragastric administration of kudancao tablets suspended in normal saline， 0.705g/(100 g.d)，2 times/day and for 5 times， then intratracheal instillation of 5 mg/kg of Bleomycin 1h later ）. Rats in all groups were scraficed 14d and 28d after intratracheal instillation. Alkali hydrolysis method was used to detect the HYP content in lung tissues. The pathological changes were observed with HE staining and silver staining. Results　Compared with the normal control group and normal saline group， the HYP content in the lung tissues of rats in model group increased significantly（P＜0.01）. Compared with the model group， the HYP content in the lung tissues of rats in kudancao tablets group decreased significantly（P＜0.01）. Pathological examination showed that significant fibrotic changes were found in lungs of rats in model group，while the fibrotic changes were ameliorated in lungs of rats in kudancao tablets group. Conclusion　Kudancao tablets may decrease the hydroxyproline content in lung tissues， and ameliorate the fibrotic degree of lungs of rats with bleomycin-induced pulmonary fibrosis.