Platycodon grandiflorus, commonly known as balloon flower, has a long history of use in traditional East Asian medicine—particularly in Chinese, Korean, and Japanese herbal traditions—for treating respiratory ailments, including symptoms commonly associated with allergies such as cough, phlegm, and throat irritation. Its root, known as Jie Geng in Chinese medicine, is often included in herbal formulas intended to "open up" the lungs, clear phlegm, and relieve coughs, which may overlap with allergic respiratory symptoms. Traditional medical texts describe its use for “wind-cold” coughs and conditions characterized by excess mucus, but not specifically for modern allergy diagnoses like allergic rhinitis or hay fever.

Scientific research on Platycodon’s effects on allergies is limited. Some preclinical studies suggest the root’s saponins and polysaccharides possess anti-inflammatory and immune-modulating activities, which could theoretically be beneficial in allergic conditions. However, there is a lack of robust clinical trials directly evaluating its efficacy for respiratory allergies in humans. The evidence supporting its use for allergies is therefore primarily traditional, with only modest support from early-stage laboratory research. Overall, while Platycodon is traditionally used to support respiratory health, its specific application for allergic respiratory conditions remains insufficiently validated by modern science.