Educational information, not medical advice — ask your doctor or midwife.
Yarrow is a common wild plant with feathery leaves and flat white flower heads. Herbal products use the species Achillea millefolium. Old books call it milfoil, which means thousand leaf.
Folk healers reached for it in three main ways. They pressed crushed leaf onto cuts to slow bleeding. They drank the tea for fevers, cramps and poor digestion.
Human studies on yarrow are few, small and mostly not repeated. So its name rests on long use, not on strong trials. Long use is not proof that a plant works, and it is not proof that it is safe.
The short answer is that no one has shown how yarrow works in people.
In cell studies, yarrow extracts damp down some inflammation signals. In test tubes, the oil slows some bacteria and fungi. Whether either happens in your body is not established.
Older animal work linked an alkaloid called achilleine to faster blood clotting. That is the usual reason given for the old wound use. It has not been confirmed in people.
Yarrow tastes bitter. Bitter herbs may prompt more saliva and stomach juice. That is a fair idea for the digestive use, not a proven one.
Yarrow also makes some people sweat and pass more urine, which fits its old fever use. Even here, the human data are thin.
Yarrow is sold in several forms, and they are not equal in strength.
- Dried flowering tops: brewed as tea, the most common form.
- Tincture: an alcohol extract sold in dropper bottles.
- Capsules and tablets: powdered dried herb.
- Creams, salves and ointments: used on skin for minor wounds and bruises.
- Essential oil: very strong, for external use only. Never swallow it.
- Fresh leaf poultice: a folk form, crushed leaf held on a small cut.
Most products are not standardised. The label rarely tells you how much active compound is inside.
Yarrow has one of the longest records of any Western wound herb. Its Latin name points to Achilles, who was said to have used it on soldiers. Old English names include soldiers woundwort and nosebleed plant.
American folk practice and the Eclectic physicians of the 1800s kept that use going. They applied it to cuts and nosebleeds. They also gave the tea for fevers, colds and period problems.
Many Native American nations used yarrow in their own ways, for pain, wounds and stomach trouble. These records describe what healers did at the time.
Stop yarrow and get emergency help if your face, lips or tongue swell, or you struggle to breathe. These are signs of anaphylaxis (a severe allergic reaction).
Stop it and see a doctor if you get a rash, blisters or itching after use on skin.
See a doctor if bleeding does not stop after 10 minutes of steady pressure. Also go if a wound turns red, swells, weeps pus, or you run a fever.
Speak to a doctor if you bruise easily, bleed from the gums or nose, or bleed in any way that is new for you. Also check in if your symptoms last more than two weeks.
In the United States, yarrow is sold as a dietary supplement. The FDA does not check it for safety or effect before sale, and US food rules allow it in drinks only when free of thujone. In the UK and parts of the EU, some yarrow products are registered as traditional herbal medicines, based on long use rather than trials.
Evidence grades and traditional-use labels are explained in our methodology. Nothing here is medical advice.
Reviewed by the HealisticMD editorial team How we grade evidence →
The published evidence for Yarrow is weak or absent. That usually means no controlled trial has tested it, not that a trial found it ineffective — the two are different, and we grade only what has been published.
What it is typically used for, usual dose, cautions, and the study behind it where real trial data exists.
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