Polygonatum (commonly known as Solomon’s Seal, and referred to in Traditional Chinese Medicine as "Yu Zhu" or "Huang Jing") has a long history of use in traditional medicine systems, particularly in China. In traditional Chinese medicine (TCM), Polygonatum species are often used to nourish yin, moisten dryness, and relieve symptoms such as dry cough, particularly those associated with lung yin deficiency. Classical texts and modern herbal references cite its use in formulas designed to address chronic, dry, or irritative coughs, especially when accompanied by throat dryness or hoarseness. Its moistening properties are thought to help alleviate cough by hydrating mucous membranes and soothing irritation.

Despite its established traditional use, there is limited modern scientific research directly evaluating the efficacy of Polygonatum specifically for cough. Some pharmacological studies have identified polysaccharides and saponins in Polygonatum species that may have immunomodulatory or anti-inflammatory effects, which could theoretically contribute to a reduction in cough symptoms. However, these effects have not been robustly validated in clinical trials focused on cough as a primary endpoint. Thus, current use for cough relief is primarily supported by traditional practice, not by high-quality scientific evidence.

In summary, Polygonatum’s use for cough is justified by traditional medical practice, with a moderate level of traditional evidence but a lack of direct scientific validation.