Pyrrosia, particularly Pyrrosia lingua (commonly known as "Shi Wei" in Traditional Chinese Medicine), has been traditionally used in Chinese herbal medicine. Its primary uses are for supporting lung and urinary health, specifically to clear heat, promote urination, and expel phlegm. In the context of colds, Pyrrosia is sometimes included in multi-herb formulations aimed at relieving symptoms such as cough and phlegm, which are common during respiratory infections. However, its role is generally secondary and supportive, not as a primary treatment for colds.

The evidence supporting Pyrrosia's use for colds is rooted mainly in traditional practices rather than modern scientific validation. Classical Chinese medical texts and pharmacopoeias describe its utility for "lung heat" and "cough with heat and phlegm," which overlap symptomatically with some presentations of the common cold. There are very limited modern clinical or pharmacological studies directly investigating Pyrrosia for the treatment or prevention of the common cold. Thus, the strength of evidence is low and primarily historical, with its use justified by long-standing traditional practice rather than robust scientific research.