Pyrrosia (commonly known as Pyrrosia leaf or Shi Wei in traditional Chinese medicine) has a long history of use in East Asian herbal medicine, particularly within traditional Chinese medicine (TCM) systems. It is traditionally used to clear heat from the lungs, promote urination, and alleviate symptoms such as cough and bronchial congestion. Ancient and classical materia medica texts reference its inclusion in multi-herb formulas intended to treat conditions like bronchitis, cough with phlegm, or other respiratory complaints associated with "damp-heat" or "phlegm-heat" in the lungs.

However, modern scientific validation for Pyrrosia’s efficacy in treating bronchial congestion is limited. While some phytochemical studies have identified the presence of flavonoids, triterpenoids, and phenolic compounds in Pyrrosia species, rigorous clinical trials or pharmacological studies specifically linking these compounds to improved bronchial health or decongestion are lacking. Most available evidence remains anecdotal or derived from traditional use, rather than from randomized controlled trials or systematic reviews.

In summary, Pyrrosia's application for bronchial congestion is primarily justified by traditional use, with only limited scientific exploration and no high-quality clinical evidence currently available to support its efficacy for this indication.