Perilla (Perilla frutescens), also known as shiso, has a long history of use in traditional East Asian medicine, particularly in Chinese and Japanese herbal practices. It is commonly used to support respiratory health and address issues related to the sinuses, such as congestion and allergic rhinitis. The traditional justification for its use stems from its inclusion in formulas for "wind-cold" conditions and allergic symptoms. Perilla leaves and seeds are believed to have anti-inflammatory, antiallergic, and expectorant properties in traditional herbal texts.

Modern scientific research on perilla's effects on the sinuses is limited, but some in vitro and animal studies suggest that compounds in perilla, such as rosmarinic acid, may have anti-inflammatory and antiallergic effects. Small-scale studies and animal models have shown that perilla extract can modulate immune responses and reduce allergic reactions, which could theoretically support sinus health. However, robust clinical trials in humans specifically evaluating its benefits for sinus conditions are lacking.

In summary, perilla's use for supporting the sinuses is primarily justified by traditional medical systems, with only preliminary scientific evidence suggesting possible benefits. Its effectiveness for this purpose in humans has not been conclusively demonstrated in large, well-controlled studies.