Sichuan Fritillary, known botanically as Fritillaria cirrhosa and commonly called "Chuan Bei Mu" in Traditional Chinese Medicine (TCM), has a long history of use for respiratory ailments, particularly to treat congestion, cough, and phlegm. In TCM, it is classified as a "phlegm-resolving" and "cough-relieving" herb, often prescribed in formulas to address productive cough and chest congestion due to accumulated phlegm or heat in the lungs. The herb is typically used in decoctions, syrups, or as a powdered ingredient combined with honey.

Scientific studies on Sichuan Fritillary are limited, but some pharmacological research has identified alkaloids such as peimine and peiminine, which may have antitussive (cough-suppressing), expectorant, and anti-inflammatory effects in animal models. However, robust clinical trials in humans are lacking, and the majority of evidence supporting its use for congestion is based on traditional practice and centuries of empirical use in China and other East Asian countries.

In summary, the use of Sichuan Fritillary for congestion is primarily justified by traditional usage, with moderate support from laboratory research but insufficient high-quality clinical evidence. Thus, its evidence rating for this use is moderate (3/5), reflecting strong tradition and limited but suggestive scientific findings.