Sophora flavescens, known as "Ku Shen" in traditional Chinese medicine (TCM), has been used historically for a variety of ailments, including respiratory conditions. Its use for supporting or treating Chronic Obstructive Pulmonary Disease (COPD) is primarily rooted in traditional practice rather than robust scientific validation. In TCM, Sophora flavescens is believed to "clear heat," "expel dampness," and "relieve cough," which aligns with the symptomatic treatment of chronic cough and phlegm in COPD. The plant contains alkaloids such as matrine and oxymatrine, which have demonstrated anti-inflammatory, immunomodulatory, and bronchodilatory effects in laboratory and some animal studies.

However, high-quality clinical studies specifically evaluating the effectiveness and safety of Sophora flavescens in COPD patients are limited. Some small-scale studies and case reports suggest potential benefit when used as part of multi-herb formulations (such as in combination with other TCM herbs), but these often lack methodological rigor, adequate controls, or sufficient sample sizes for conclusive evidence. Systematic reviews often cite the need for better-designed clinical trials before recommending its use in standard COPD management.

In summary, while Sophora flavescens is traditionally used for respiratory symptoms that overlap with those of COPD, scientific validation is currently insufficient, and its use for COPD is supported mainly by traditional rather than rigorous scientific evidence.