Japanese arisaema (Arisaema japonicum), known as "tiannanxing" in Traditional Chinese Medicine (TCM), has a longstanding history of use in East Asian herbal traditions. Traditionally, processed arisaema tubers are used for their purported effects on "phlegm-dampness" and to help resolve conditions characterized by excessive mucus, coughing, and nasal congestion—symptoms associated with the sinus and respiratory systems. Classical TCM texts describe arisaema as a remedy for "wind-phlegm" obstructing the head, including sinus congestion, dizziness, and headaches. However, its use requires caution, as raw arisaema is toxic and must be specially processed to reduce toxicity. In terms of scientific evidence, there is limited modern research specifically evaluating Japanese arisaema for sinus health. Some in vitro and animal studies have investigated related species, suggesting anti-inflammatory and expectorant properties, but these findings have not been robustly confirmed in human clinical trials. The evidence for its efficacy in supporting the sinuses remains primarily based on historical and traditional use rather than rigorous scientific validation. In summary, Japanese arisaema's use for supporting the sinuses is deeply rooted in traditional medicine systems, particularly in Asia. While there is some preliminary pharmacological evidence, it remains insufficient to strongly support its effectiveness by modern standards.