Yarrow
Achillea millefolium: A fragrant herb with ancient roots and modern uses in traditional medicine.
Yarrow, scientifically known as Achillea millefolium L., is a member of the Asteraceae (daisy) family, with a global distribution and various names like milfoil, thousand-leaf, or old man’s pepper, owing to its fragrant aroma. Its genus name, Achillea, has origins in Greek mythology, as Achilles reputedly used yarrow leaves to staunch bleeding wounds. This plant is renowned for its ability to heal wounds and address blood-related ailments, resulting in names such as bloodwort, soldier’s woundwort, military herb, sanguinary, nosebleed, or knight’s milfoil.
Evidence of yarrow's historical significance stretches back 60,000 years, with yarrow pollen discovered at Shanidar IV, an ancient Neanderthal burial cave in Iraq. This suggests its possible early use in rituals or medicine. In the first century AD, the European classical medical tradition documented yarrow's use in surviving texts authored by Pliny the Elder and Dioscorides.
Furthermore, recent DNA analysis has identified yarrow among the plants found in two pressed tablets of plant material recovered from a collection of medical supplies on a Roman shipwreck off the Tuscan coast, dating back to between 140 and 120 BC. This discovery underscores its enduring relevance in historical medicine.
Throughout the centuries, cultures worldwide have recognized and harnessed yarrow's therapeutic benefits. Today, it continues to be sold as a panacea in herbal supplements and ointments, a testament to its enduring healing properties.
Botanical Description
Yarrow is a a perennial herb that spreads from a small rhizome and has a wide distribution across Europe, Asia, South America, and North Africa. It has also naturalized in various soil types throughout temperate North America, including all U.S. states, Canada, and Greenland. Yarrow thrives in unshaded, open environments like cliffs, meadows, roadsides, and waste grounds.
Yarrow usually reaches heights of 12 to 24 inches and appears gray-green due to numerous small, silky white hairs covering it. Its species name, ‘millefolium’ (thousand-leaves), refers to its segmented foliage, ranging in size from 3-20 cm in length and 1-6 cm in width. The leaves are fern-like, arranged alternately along the stem, with clusters at the base of flowering stems. When crushed or dried, the leaves emit a spicy aroma and have a bitter, astringent taste when consumed.
Traditional Uses
Ritual applications
Perhaps due to its potent healing abilities, yarrow has been regarded as possessing special spiritual or magical properties in many cultures. In East Anglia, yarrow, known as 'nosebleed,' was used as a plant for divining future love. A leaf would be placed inside the nose, and a rhyme recited:
Yarroway, yarroway, bear a white blow, if my love loves me, my nose will bleed now —The Englishman’s Flora.
In ancient China, yarrow often held a sacred role as a ritual plant symbolizing the balance between yin and yang. In North America, Native American tribes, alongside their extensive medicinal uses for the plant, would also burn yarrow flowers for ceremonial smoke. According to the Native American Ethnobotany Database, here are just a few examples of the various medicinal uses reported for different tribes:
Abnaki
Infusion of whole plant given to children for colds.
Used for fevers.
Algonquin
Crushed leaves used as a snuff for headaches.
Leaves for poultices.
Used for respiratory disorders.
Bella Coola
Leaves pounded, heated and used for breast abscesses.
Leaves pounded, heated and used for burns.
Poultice of leaves and eulachon grease applied to the chest and back of children for bronchitis.
Blackfoot
Infusion of plant applied to sores.
Infusion of plant taken as a diuretic to pass the sickness with the urine.
Infusion of leaves taken when labor pains started and to ease the delivery.
Infusion of plant taken for sore throats.
Cherokee
Infusion taken for fever.
Used for bowel complaints.
Used for bloody piles.
Dried leaves smoked for catarrh.
Iroquois
Decoction or infusion of plants, bark and roots taken for vomiting.
Infusion of plants taken when 'sore through the joints.'
Infusion of leaves given to babies with any kind of fever.
Decoction of plant fragments taken for digestive cramps.
Traditional uses today
In the southwestern U.S., Hispanics refer to yarrow as "plumajillo" (Spanish for ‘little feather’) and currently utilize it to treat various conditions such as colds, anemia, diarrhea, flatulence, and as a diuretic. In Italy and East India, yarrow is well-known for its antipyretic properties. In India, it is specifically employed for medicated vapor baths to alleviate fevers or consumed as a tonic to alleviate gas and cramping. In Russia, yarrow was administered to nursing mothers to boost milk supply, reduce high blood pressure, stimulate bile flow from the liver and gallbladder, and prevent the formation of kidney stones and gallstones. In Germany, yarrow is occasionally used as a substitute for iodine for minor skin lacerations in children and to address mood swings or depression. German herbalists also recommend combining yarrow with fennel as a hypnotic aid and for post-surgical recovery.
Chemical Composition
Many studies have been conducted on yarrow in effort to understand its chemical composition. The main classes of compounds found in yarrow include phenols, flavonoids, sequiterpenoids, monoterpenes, and proazulenes. To read more about yarrow chemistry, refer to this review paper.
Pharmacology
Based on the extensive list of traditional applications of yarrow in medicine, it is unsurprising that there are many pharmacological properties of the plant that have been revealed in scientific studies. Laboratory studies conducted in test tubes and in animals have revealed that yarrow exhibits choleretic, antimalarial, antioxidant, antihypertensive, antimicrobial, antispasmodic, hepatoprotective, gastroprotective activities.
In addition to these laboratory studies, a number of clinical studies have also revealed some interesting findings on yarrow. Here, I summarize a few of the major clinical findings:
Episiotomy Wound Healing: Hajhashemi et al. (2016) conducted a double-blind clinical trial with 140 primiparous women. They found that A. millefolium ointments significantly reduced pain severity and improved wound healing after episiotomy.
Dysmenorrhea Relief: Jenabi and Fereidoony (2015) conducted a double-blind randomized clinical trial with 91 female students. They discovered that yarrow flowers, in tea bag form, effectively relieved primary dysmenorrhea pain (painful menstruation) for up to two months.
Mosquito Biting Reduction: A study reported by Jaenson et al. (2006) found that yarrow leaf extract significantly reduced mosquito biting by Aedes mosquitoes in human volunteers.
Safety and Toxicology
Yarrow is generally considered safe, but caution is advised. While the FDA classifies it as non-poisonous and approves its use in alcoholic drinks, there have been reports of genotoxicity associated with its essential oil. Long-term exposure did not reveal significant health hazards, but slight changes in liver weight, cholesterol, and glucose levels occurred. Reproductive toxicity showed increased abnormal sperm with high extract doses in male rats, and yarrow caused allergic contact dermatitis in some individuals due to sensitizing compounds. Overall, yarrow's safety is generally acceptable, but extreme dosages and individual sensitivities should be considered.
The Takeaway
The use of yarrow in medicine dates back millennia, possibly predating humans, based on pollen remnants found in a Neanderthal cave site. Due to its wide distribution, yarrow has found its way into the medical practices of many cultures. Scientific and clinical studies on the plant offer evidence of efficacy for many of these uses. This is one of my favorite medicinal plants, not only because of its wide range of medical properties but also because of its beauty and unique fragrance.
Yours in health, Dr. Quave
Cassandra L. Quave, Ph.D. is a scientist, author, speaker, podcast host, wife, mother, explorer, and professor at Emory University School of Medicine. She teaches college courses and leads a group of research scientists studying medicinal plants to find new life-saving drugs from nature. She hosts the Foodie Pharmacology podcast and writes the Nature’s Pharmacy newsletter to share the science behind natural medicines. To support her effort, consider a paid or founding subscription, with founding members receiving an autographed 1st edition hardcover copy of her book, The Plant Hunter.
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