Yarrow (Achillea millefolium) has a long history of traditional use in herbal medicine, including for respiratory health. Folk practitioners in various cultures have used yarrow in teas, steams, and tinctures for symptoms associated with colds, flu, and sinus congestion. The plant contains flavonoids, sesquiterpene lactones, and volatile oils, which are believed to have anti-inflammatory and mild antimicrobial effects. These properties form the basis for its use in supporting the sinuses, particularly in easing congestion and inflammation of mucous membranes.

However, while the traditional use is well documented, scientific studies specifically evaluating yarrow’s effects on sinus health are limited. Most contemporary research on yarrow focuses on its general anti-inflammatory and wound-healing properties rather than direct action on sinus tissues or conditions like sinusitis. Thus, while its use for sinus support is justified by tradition, it lacks strong clinical evidence demonstrating significant efficacy for this specific application.

In summary, yarrow’s reputation for supporting the sinuses is based primarily on traditional practices and its general anti-inflammatory properties, rather than robust scientific validation targeted to the sinus body system.