Platycodon, commonly known as balloon flower (Platycodon grandiflorus), has a long history of use in traditional East Asian medicine, particularly in Chinese, Korean, and Japanese practices. In Traditional Chinese Medicine (TCM), the root of Platycodon (called Jie Geng) is a well-known ingredient in herbal formulas aimed at addressing respiratory conditions, especially those involving congestion and phlegm. It is classified as an herb that "opens up the lung qi" and "expels phlegm," and is frequently included in formulas for productive cough, sore throat, bronchitis, and chest congestion. The traditional use is well documented in classic herbal texts and is still common in contemporary East Asian herbal practice.

Scientific studies have investigated Platycodon's saponins (notably platycodin D) for their expectorant and anti-inflammatory properties. Some animal and in vitro studies suggest it may help reduce airway inflammation and promote the expulsion of mucus. However, while these studies provide plausible mechanisms, rigorous clinical trials in humans are limited, and the existing evidence is not robust. Therefore, while scientific investigation is ongoing, the primary justification for its use in treating congestion remains traditional, supported by centuries of empirical use rather than strong modern clinical data. The evidence level is moderate from a traditional perspective but limited from a scientific one.