In Greek mythology, the warrior Achilles applied summerblooming yarrow to his soldiers' battle wounds -- a legend that led to the herb's botanical name, Achillea millefolium. The hardy wildflower thrives in poor soil, producing caps of yellow, white and light pink flowers. In many countries (including this one), it's considered a weed. But the plant has a medicinal history that dates back thousands of years, and has been dubbed bloodwort, staunchweed and nosebleed for its ancient use in treating bleeding injuries.
Uses: In the U.S., yarrow supplements are most commonly marketed for fevers, colds, toothaches, snoring and digestive problems. The herb has also been used, particularly in Europe and Russia, to ease menstrual cramps, boost liver health and stimulate the appetite.
Dose: About one teaspoon (roughly 4 grams) of dried yarrow, or 300 to 600 milligrams in capsule form, daily. For snoring, manufacturers often recommend taking the supplement before bed. Yarrow is also sold in teabags and as a liquid extract.
Precautions: Some people are allergic to yarrow; the plant belongs to the same botanical family as ragweed and daisies. The herb is not recommended for pregnant women, because animal studies suggest it may increase the risk of having a low-birth-weight baby. Yarrow may also make users more sensitive to sunlight.
Research: Ongoing test-tube studies show that some of the herb's chemical components reduce inflammation and, to a lesser degree, pain and bacterial activity. Some components also appear to slow the growth of tumors in vitro. Animal studies support the claim that yarrow helps increase digestive secretions and eliminate muscle spasms in the digestive tract. Experiments also show that yarrow acts as an astringent, meaning that it tightens and contracts tissues, which can help stop bleeding. Human clinical trials on the herb, however, are rare. One study, published last year in the Journal of the American Academy of Dermatology, examined the effect of yarrow in combination with other herbs on skin rash, and another studied its effect on gingivitis. In both cases, the remedy performed no better than a placebo.
Dietary supplement makers are not required by the U.S. government to demonstrate that their products are safe or effective. Ask your healthcare provider for advice on selecting a brand.