OBJECTIVE:To investigate the effect of Daiqin phlegm-expelling pill,prepared with Traditional Chinese Medicine (TCM),on the development of inflammation in Sprague-Dawley (SD) rats with chronic obstructive pulmonary disease (COPD) induced by lipopolysaccharide (LPS) and smoke,and to identity the possible underlying mechanism.METHODS:Sixty male rats were divided into 6 groups (healthy control group,untreated group,Daiqin phlegm-expelling pill low,middle and high dose,and ambroxol hydrochloride tablet group).COPD was established in SD rats by sootiness and tracheal instillation with LPS.The rats were treated with Daiqin phlegm-expelling pill at the indicated doses for 28 d,the inflammatory cells in bronchoalveolar lavage fluid (BALF),the concentration of tumor necrosis factor-α (TNF-α),interleukin (IL)-8 and IL-6 in blood and the inflammation in lung were evaluated.RESULTS:The number of inflammatory cells in the BALF and TNF-α,IL-8 and IL-6 level in plasma were significantly reduced in rats with COPD when treated with Daiqin phlegm-expelling pill or ambroxol hydrochloride tablet,compared with those without any treatment.The Daiqin phlegm-expelling pill treated rats with COPD had a attenuated inflammation in lung tissue,compared with the untreated group.CONCLUSION:Daiqin phlegm-expelling pill can significantly restrain the airway inflammation in rats with LPS-smoke induced COPD.