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Yarrow - Medicinal Uses, Interactions, Side Effects, Dosage

Yarrow

Yarrow is a common name for many similar species and subspecies of Achillea; Achillea mille folium (common yarrow) is also referred to as Achillea, milfoil, and soldier's woundwort. It is a member of the Asteraceae family. The plant is named after Achilles, who was fabled to have used yarrow to treat wounds and staunch bleeding. The stems, leaves and flower are used medicinally.

Uses and Benefits:

Yarrow is reputed to have a host of beneficial effects in many cultures. It is variably described as a diaphoretic, antipyretic, astringent, analgesic, anti-inflammatory, spasmolytic, and diuretic. Traditional indications include fevers, colds, digestive disorders, hemorrhoids, menstrual cramps, menorrhagia, and urogenital problems, and it is also used for wounds, bruises, sprains, and rashes. In the U.S., yarrow is approved as a flavoring in alcoholic beverages when the product is thujone-free.

Pharmacology:

Many organic constituents have been isolated from yarrow, including fatty acids, flavonoids, tannins, coumarins, alkaloids, and a volatile oil. The oil contains sesquiterpene lac­tones, terpineol, camphor, thujone and many other constituents. Extracts contain variable amounts of the anti-inflammatory azulene or chamazulene; these may be found only in subspecies of A. mille folium that do not include common yarrow. Azulene, chamazulene, and the flavonoids have demonstrated anti-inflam­matory activity, while the flavonoids have the greatest antispas­modic activity in animal studies. Yarrow extracts are reported to have antipyretic, sedative, antispasmodic, diuretic, hypoglycemic, and hypotensive actions in animal models, and antibacterial and antifungal activity in vitro. Intravenous injection of an alkaloid constituent (achilleine) decreased bleeding time by 32% in rabbits, potentially supporting its use as a hemostatic agent by herbalists.

Clinical Trials:

There are few clinical trials of yarrow, and none using the herb as a monopreparation. In 34 patients with acute viral hepatitis, a combination herbal product from India (Liv-52) that included yarrow and seven other herbs reduced clinical symptoms and bilirubin levels faster than placebo in a double­blind, randomized trial over 6 weeks. In a more recent random­ized, controlled trial, an herbal mixture of yarrow, juniper, and nettle used as a mouthwash on 45 subjects with moderate gin­givitis failed to affect plaque growth and gingival health compared to a placebo.

Adverse Effects:

Yarrow is considered to be well tolerated, with no known side effects.

Side Effects and Interactions:

Based on animal studies, large doses of yarrow may theoretically potentiate sedatives and antihypertensives, or counteract anticoagulants. These properties have not been studied or reported in humans, and clinical effects are unlikely.

Cautions:

Allergic subjects may develop contact dermatitis and systemic allergic manifestations, and patients with known sensitivity to Asteraceae plants (e.g., chrysanthemum, daisy, chamomile) may be more susceptible. A minor component of the volatile oil is thujone, which is a toxic chemical in large amounts. The small concentration found in the herb is unlikely to cause toxicity; however, thujone is reputed to be an abortifacient and to affect the menstrual cycle. Yarrow's safety in pregnancy and during breast feeding have not been established.

Preparation & Doses:

Leaves, stems, and flower tops are employed in a variety of preparations, including decoctions, infusions, and tinctures. There is no standardized dose or formulation. A typical oral dose is 1-2 g dry herb or its equivalent, three times daily. In the U.S., the herb is available in oral capsule form, or in a variety of liquid extract products.

Summary Evaluation

Clinical studies are few; thus, there is insufficient data to make evidence-based recommendations for the use of yarrow monopreparations. Yarrow extract may have some clinical benefit as a topical astringent or anti-inflammatory agent, but this use is based on anecdotal experience or tradition, and has not been substantiated in clinical studies. The alleged benefits of oral dosing for hepatitis and other disorders also have not been validated by controlled
trials using monopreparations. Yarrow is likely to be safe and well tolerated for most patients (except those allergic to the plant), based on a long history of traditional use.

About Author

Steve Mathew is a writer, who writes many great articles on herbal medicines for common ailments and diseases. For more information on herbal remedies and home remedies visit our site on health care.

Source: ArticleTrader.com