Balloon Flower (Platycodon grandiflorus) root, also known as Jie Geng in traditional Chinese medicine (TCM), has a long history of use for treating respiratory conditions, especially coughs, including dry cough. In TCM, Balloon Flower is considered to have properties that "disperse lung Qi" and "expel phlegm," and is often included in herbal formulas aimed at soothing sore throats and treating coughs due to its purported ability to open and ventilate the lungs. Historical texts and materia medica document its use for both productive and non-productive (dry) coughs.

Modern scientific research has investigated some of the bioactive compounds in Balloon Flower root, such as saponins (notably platycodin D), which demonstrate anti-inflammatory and expectorant effects in laboratory and animal studies. Some studies have shown that extracts of Balloon Flower root can reduce airway inflammation and suppress cough reflex in animal models. However, robust clinical trials in humans are limited, and most of the evidence supporting its use for dry cough comes from its established role in traditional medicine systems rather than from large-scale scientific validation.

In summary, the use of Balloon Flower for dry cough is well-supported by traditional practice, with some promising but still preliminary scientific data. Its effectiveness in humans for this specific indication remains to be conclusively proven in rigorous clinical studies.