Cowherb, also known as Vaccaria segetalis or Vaccaria hispanica, is an herb commonly used in Traditional Chinese Medicine (TCM). In TCM, Cowherb seed (Wang Bu Liu Xing) is traditionally employed for its purported abilities to promote blood circulation, resolve swelling, and treat certain inflammatory conditions. Its historical uses include applications for gynecological disorders, lactation issues, and, less commonly, as part of formulas for respiratory ailments including chronic cough and phlegm, which can overlap symptomatically with Chronic Obstructive Pulmonary Disease (COPD). However, the use of Cowherb specifically for COPD is based on traditional practice rather than robust scientific evidence.

Scientific studies directly investigating Cowherb for COPD are extremely limited. Some in vitro and animal studies have reported anti-inflammatory and immunomodulatory effects of the herb’s extracts, which could theoretically benefit chronic inflammatory airway diseases. Nevertheless, high-quality clinical trials in humans with COPD are lacking, and there is no consensus in conventional medicine supporting its efficacy for this indication. Therefore, while Cowherb’s use for respiratory issues has roots in traditional medicine, particularly in multi-herb formulas, scientific validation for its effectiveness in COPD remains insufficient.

In summary, Cowherb is used for COPD primarily based on traditional beliefs and practices, with limited preclinical evidence but no substantial clinical proof of benefit for this specific condition.