What is Yarrow?

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.

How does Yarrow work?

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.

What forms does Yarrow come in?

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.

Where it comes from:

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.

What does Yarrow help with?

• Minor cuts, grazes and nosebleeds: This is yarrow's oldest and best known use. Healers packed crushed leaf onto small cuts to slow bleeding. Good human trials for this use do not exist. One small trial of a yarrow ointment on stitches after childbirth reported less pain and better healing. It was small and has not been repeated. Deep, gaping or dirty wounds are a medical matter, not a home one.
• Fevers, colds and flu: Tradition treated yarrow tea as a sweating herb for early fevers. It was often mixed with elderflower and peppermint. There are no good human trials behind this. Any warmth or sweating you feel from a hot tea is not proof the herb changed the illness.
• Period cramps and heavy periods: Folk and Eclectic writers used yarrow for cramps and for heavy bleeding. The two claims pull in different directions, which is worth noting. Human evidence is thin. A few small trials used herbal mixes that included yarrow, so the herb cannot be judged on its own. If you are pregnant or might be, do not use it.
• Poor appetite and mild indigestion: Yarrow is a classic bitter tonic. Bitter herbs were taken before meals to wake up the appetite. Some European products are registered for mild stomach and gut cramps and for loss of appetite. That registration rests on long use, not on new trials.
• Bruises and sore skin: Creams and compresses were used on bruises, sprains and sore skin. There is almost no human trial evidence here. Skin allergy to yarrow is common enough that a small patch test first is sensible.

Which foods are rich in Yarrow?

Yarrow is a herb, not a food nutrient, so no food is rich in it. Young leaves were eaten in small amounts in salads in the past, and the bitter herb appears in some European liqueurs. US food rules allow yarrow in drinks only if the preparation is free of thujone.

What are the side effects of Yarrow?

• Skin rash, itching or blisters where it touches the skin
• Allergic reaction in people sensitive to ragweed, daisies and related plants
• Easier sunburn on treated skin (photosensitivity)
• Stomach upset or nausea
• Headache or drowsiness
• Rare severe allergic reaction with swelling and trouble breathing

Good to know:

Most people who use yarrow briefly have no trouble.

Skin reactions are the most common problem. They happen with the fresh plant and with creams.

People allergic to ragweed, daisies, marigold or chrysanthemum react more often. Severe allergy is rare, but it is real.

How much Yarrow should you take?

• Recommended daily: This page reports what labels carry. It is not advice for you. Dried herb tea labels usually suggest about 1 to 2 grams of dried flowering tops per cup, up to three cups a day. Tincture and capsule strengths differ widely, so the product label is the only guide. Skin creams are used as directed on the pack. The essential oil is for external use only and is never swallowed. If you take prescription medicines, ask a pharmacist or doctor before you start.
• Best time of day: Timing is mostly tradition, not evidence. Bitter uses, such as poor appetite, were timed shortly before meals. Sweating teas for fever were taken in the evening, in bed. For skin creams the time of day does not matter.
• With or without food: For appetite and digestion, bitters were taken shortly before food. If the tea upsets your stomach, taking it with food may help. Capsules are usually taken with water and a meal.
• Time to effect: Tea effects such as warmth or sweating, if they happen, come within an hour. Digestive effects from a bitter herb are usually felt around the meal. Skin uses are judged over days. It may also do nothing at all. That is a real possible outcome here.
• How long to take it: Traditional use was short: a few days to about two weeks, for a clear reason. European traditional herbal labels often tell people to see a doctor if symptoms last longer than two weeks. Long, unbroken use has not been studied for safety.