This article will investigate the application of Xiaoqinglong Decoction（ 小青龙汤） in chronic obstructive pulmonary disease（ COPD） from the perspective of formula-syndrome relation. Xiaoqinglong Decoction can be widely used in COPD patients with external cold with internal fluid retention syndrome and phlegm-dampness accumulating in the lung syndrome. The formula could be used for patients of both acute stage or stable stage of COPD with the syndrome of internal cold fluid and external cold

the main symptoms including cough

much thin sputum

asthma

short of breath

and dyspnea.