ObjectiveTo investigate the clinical effect and mechanism of Chinese heat-clearing and phlegm-resolving recipe in the treatment of acute exacerbation of chronic obstructive pulmonary disease (AECOPD). MethodsA randomized controlled trial (RCT) was conducted. A total of sixty in-patients with AECOPD of phlegm heat and phlegm turbidity in lungs were randomly allocated to treatment group and control group with an equal number of patients between October 2009 and March 2010. The treatment duration was 10 days. Symptom scores of traditional Chinese medicine (TCM), pulmonary function, white blood cell count, polymorphonuclear neutrophils, C-reactive protein and the plasma concentration of bactericidal/permeability increasing protein (BPI) and interleukin (IL)-8 and IL-10 were detected. ResultsFor TCM syndrome of phlegm heat and phlegm turbidity, there was a statistical difference between the two groups after treatment (P<0.05). Cough, sputum amount, expectoration and coated tongue were improved obviously in the treatment group (P<0.05). The total explicit efficiency rate and effective rate were 56.0% and 84.0% in the control group and 82.1% and 92.9% in the treatment group respectively. The total explicit efficiency rate was significantly different between the two groups (P<0.05), while the total effective rate was not significantly different (P>0.05). Plasma concentration of IL-8 decreased markedly in the treatment group and IL-10 and BPI increased obviously. There was no significant difference in the change of BPI, IL-8 between the two groups (P>0.05), except for IL-10 (P<0.05). ConclusionChinese heat-clearing and phlegm-resolving recipe can improve signs and symptoms of TCM in the treatment of AECOPD (phlegm heat and phlegm turbidity in lungs), by the potential mechanism of increasing the level of IL-10.