Perilla oil, derived from the seeds of Perilla frutescens, has a traditional history of use in East Asian medicine, but there is also some scientific investigation into its effects on respiratory allergies. The oil is rich in alpha-linolenic acid (ALA), an omega-3 fatty acid, and contains other bioactive compounds such as rosmarinic acid. Several small clinical and preclinical studies have suggested that perilla oil may help mitigate allergic responses, especially in the context of allergic rhinitis and asthma.

Animal studies have shown that perilla oil and its extracts can reduce airway inflammation and suppress the production of inflammatory cytokines associated with allergic reactions. Human trials are limited but promising. For example, a small randomized controlled trial published in International Archives of Allergy and Immunology (2000) found that supplementation with perilla seed oil improved symptoms in patients with seasonal allergic rhinoconjunctivitis compared to placebo, though the study size was small and further research is needed.

Overall, while there is some scientific evidence supporting the use of perilla oil for respiratory allergies, it remains limited in scope and quality. Larger, high-quality human studies are needed to firmly establish efficacy and optimal dosing. Thus, the evidence rating is moderate (2 out of 5).