Objective:To investigate the antioxidant effects of addition and subtraction Bufei decoction（ASBD） on pulmonary fibrosis（PF） in rats.Method:Forty male Sprague-Dawley rats were divided randomly into sham operation group

model group

ASBD group.The PF model was reproduced by intratracheal injection of bleomycin.ASBD group was given traditional Chinese medicine decoction（ig

2 times to clinic dose

16 g · kg-1） starting from 2 days after operation.The sham operation group and model group were given the same amount of normal saline.The blood and lung tissue of rats were took on the 14 d and 28 d.The superoxide dismutase（SOD） activity and malondialdehyde（MDA） content in serum were measured.The content of hydroxyproline in lung tissue was detected.The mRNA of extracellular SOD（ECSOD） was measured by real-time PCR.Result:ASBD significantly improved the survival state of PF rats

reduced content of hydroxyproline in the lung tissue

decreased the level of MDA in the serum

improved the expression of ECSOD mRNA.Conclusions:ASBD could improve the survival rate of PF rats

and the fibrosis index.The mechanism might be related to decrease in the level of serum MDA and up-regulation of the expression of ECSOD mRNA.