Perilla (Perilla frutescens) has a long history of use in traditional East Asian medicine, particularly in Chinese and Japanese herbal practices. In traditional Chinese medicine (TCM), perilla leaves are often used to help support the respiratory tract, including the mucus membranes of the nose, throat, and lungs. Practitioners believe perilla can help "disperse wind-cold" and "regulate qi," which may relate to easing symptoms such as cough, stuffy nose, and mild irritation of the mucus membranes. The herb is commonly included in formulas aimed at supporting the body's natural defenses and soothing minor irritations of the airways.

From a scientific standpoint, there is some preliminary research suggesting that perilla contains compounds (such as rosmarinic acid and certain flavonoids) with anti-inflammatory and antioxidant properties. Some animal and cellular studies have shown potential for these compounds to modulate allergic responses and reduce inflammation, which could theoretically benefit the mucus membranes. However, robust clinical trials in humans are lacking, and there is no direct validation that perilla alone supports mucus membrane health in the context of human respiratory conditions.

In summary, the use of perilla to support mucus membranes is primarily justified by traditional practices rather than strong scientific evidence. The evidence rating is moderate due to the extensive traditional use but limited modern clinical validation.