Objective To explore the clinical effectiveness and safety of Huanglong Kechuan Capsule（黄龙咳喘胶囊） in the treatment of stable chronic obstructive pulmonary disease（SCOPD） with lung-kidney qi deficiency and phlegm-heat constraint in the lung syndrome（LQD-PCL）. Methods A randomized

double-blinded

placebo-controlled

multi-centered clinical trial was designed

in which 240 SCOPD patients with LQD-PCL syndrome were randomized into treatment group（160 cases） and control group（80 cases）. Patients in both groups were given routine western medicine; additionally

Huanglong Kechuan Capsule and its placebo

were orally administered in the treatment group and control group

respectively

with 1.2 g per time

three times daily

for three months. Major symptoms including cough

expectoration

shortness of breath and minor symptoms including fatigue

spontaneous sweating

aversion to wind

soreness of waist and knees

tinnitus and dizziness were assessed before treatment

one month and three months after treatment. The effect on traditional Chinese medicine（TCM） symptoms were compared between two groups after treatment; 6-minute walking distance（6 MWD）

chronic obstructive pulmonary disease assessment test（CAT） score

forced expiratory volume in the first second（FEV1）

forced vital capacity（FVC） and modified medical research council（mMRC） dyspnea scale were assessed before treatment

one month and three months after treatment; the severity of the disease

the combined medication

and adverse events were recorded and compared between groups before and after treatment. Results The total effective rate of TCM symptoms in the treatment group was 81.65% and that in the control group was 41.25%

with statistically significant differences between two groups（P<0.05）. The symptom scores of cough

expectoration

shortness of breath

fatigue

spontaneous sweating

aversion to wind

susceptibility to colds

weakness in the waist and knees

tinnitus and dizziness

CAT score

mMRC score

and frequency of acute attacks in the treatment group were significantly decreased

while FEV1 and 6 MWD increased one month and three months after treatment compared to those before treatment（P<0.05）; the comparison on these outcomes before and after treatment in the control group were not statistically significant（P>0.05）. The severity of the disease was reduced more in the treatment group than in control group after treatment（P<0.05）. The combined medications were not statistically different between groups（P>0.05）. There were no serious adverse events in either group. Conclusion Huanglong Kechuan Capsule can improve the symptoms of SCOPD patients with LQD-PCL syndrome

improve exercise tolerance and quality of life

and is of sound safety.