Perilla (Perilla frutescens), commonly known as shiso, has a long history of use in East Asian traditional medicine, particularly within Chinese herbalism. Traditionally, perilla leaves and seeds have been used to support respiratory health, and are believed to help with symptoms such as cough, congestion, and asthma. In traditional Chinese medicine (TCM), perilla is classified as having the ability to "release the exterior" and "dispel wind-cold," terms that relate to treating early-stage colds and flu, which may involve bronchial symptoms.

Scientific evidence supporting perilla's use for bronchial or respiratory support is limited, but there are some preclinical studies that suggest potential benefits. Certain constituents in perilla, such as rosmarinic acid and luteolin, have demonstrated anti-inflammatory and anti-allergic effects in animal models. Some studies indicate that perilla extracts may help inhibit allergic airway inflammation, which could be relevant for asthma or bronchial irritation. However, robust clinical trials in humans are lacking, and the majority of evidence is anecdotal or based on traditional usage.

In summary, while there is a strong traditional basis for the use of perilla in supporting the bronchial system, scientific validation is limited and primarily confined to basic laboratory studies. Therefore, its use is primarily justified by traditional practice rather than conclusive scientific evidence.