Yarrow has a unique combination of constituents normally found singly in other plants, and has been a popular remedy in Europe for centuries. It contains aspirin-like compounds, which can be helpful at the onset of illness to reduce fever, and for many types of swelling and pain.
Also helpful in the phase of “coming down” with something is Yarrow’s apparent ability to stimulate perspiration and overall elimination of wastes, and its balancing effect on circulation. The combination of painkilling and anti-inflammatory compounds, which have a particular affinity for the joints, and its waste-elimination effects make it potentially useful in arthritis and gout. In addition to the aspirin-like chemicals, Yarrow contains azulene, also found in Chamomile, making Yarrow of possible benefit to spasmodic problems of the stomach and intestines.
Finally, Yarrow is high in astringent tannins, leading to its old folk use for unwanted bleeding, diarrhea, and hemorrhoids, and for problems of the female reproductive system and urinary tract.