Chekiang Fritillary, also known as Fritillaria thunbergii or "Zhe Bei Mu," is a traditional Chinese medicinal herb commonly used in the treatment of coughs, particularly spasmodic or persistent coughs with thick phlegm. Its use is well-documented in classical Chinese medical texts, where it is described as having properties that clear heat, moisten the lungs, and resolve phlegm. The traditional basis for its use largely stems from its inclusion in various classical formulas aimed at treating “phlegm-heat” type coughs.

Modern pharmacological studies have identified several bioactive alkaloids in Fritillaria thunbergii (such as peimine and peiminine), which have demonstrated antitussive (cough-suppressing) and expectorant effects in animal models. However, robust clinical trials in humans are limited, and most evidence comes from in vitro studies or animal experiments. Therefore, while there is some preliminary pharmacological evidence supporting its traditional use, high-quality scientific validation in humans is lacking.

In summary, the use of Chekiang Fritillary for spastic or persistent coughs is primarily justified by tradition, with some supporting evidence from pharmacological studies, but insufficient clinical data to make strong scientific claims.