Scallion (Allium fistulosum), also known as green onion, has been used in traditional medicine systems, particularly in East Asia, to support respiratory health, including the sinuses. In Traditional Chinese Medicine (TCM), scallion is considered to have warming properties and is included in herbal remedies intended to expel wind-cold and relieve symptoms like nasal congestion, especially in the early stages of colds and flu. Historical texts describe its use for "unblocking the yang" and dispersing pathogens from the body's surface, sometimes recommending topical application or ingestion as a soup ingredient for mild respiratory complaints.

From a scientific perspective, evidence supporting scallion’s effectiveness for sinus support is minimal. Scallions contain compounds such as allicin, which have mild antimicrobial properties; however, no clinical trials have specifically evaluated scallion for sinusitis or sinus health. Most available studies focus on related Allium species (like garlic) and their general antimicrobial or anti-inflammatory effects, not on direct sinus-specific outcomes. Therefore, while traditional usage is well-documented, modern scientific validation is lacking, and evidence should be considered anecdotal rather than clinically substantiated.