Fritillaria, particularly the bulbs of species such as Fritillaria cirrhosa and Fritillaria thunbergii, has a long history of use in Traditional Chinese Medicine (TCM) for supporting the bronchial and respiratory systems. In TCM, these bulbs are collectively referred to as "Chuan Bei Mu" and "Zhe Bei Mu" and are commonly prescribed to alleviate coughs, clear phlegm, and relieve symptoms of bronchitis and other lung-related disorders. The traditional rationale is that Fritillaria bulbs are believed to “moisten the lungs” and “transform phlegm,” making them suitable for treating both dry and productive coughs.

Scientific studies evaluating Fritillaria are limited but provide some support for its traditional use. Some pharmacological research has identified steroidal alkaloids and saponins in Fritillaria bulbs that exhibit antitussive (cough-suppressing), expectorant, and anti-inflammatory effects in animal models. However, most clinical evidence is anecdotal or derived from small, lower-quality studies, and robust, large-scale human trials are lacking. Thus, while the traditional use of Fritillaria for bronchial support is well established and there is some preliminary pharmacological backing, the scientific validation is not strong enough to rate higher than moderate.

In summary, the justification for using Fritillaria to support the bronchial system is primarily traditional, with some limited scientific evidence suggesting potential efficacy.