Yarrow (Achillea millefolium)
What Is Yarrow?
Yarrow is the common name for Achillea millefolium, a plant of the Asteraceae family, native to temperate Eurasia. The material in circulation is aerial parts (flower, leaf) — leafy growth taken above ground. The common name Yarrow and the botanical name Achillea millefolium refer to the same material, and labels may use either — a detail that matters when related species in the same genus are not interchangeable. Its character is described as herbaceous, slightly sweet, camphoraceous, which is often how the raw material is checked for quality.
Yarrow entered the reference literature through use rather than through chemistry. Older sources are concerned with where it grows, when it is gathered and how it is prepared, questions that still shape the material on sale today. Beyond its practical use it carries cultural associations — named after Achilles — used to heal warriors' wounds and i Ching divination traditionally uses yarrow stalks.
Today most searches for Yarrow come from people reading about wound healing, colds & flu, antibacterial and fever, or checking how it sits alongside a medication they already take. The use most often documented in the literature is hemostatic — may stop minor bleeding (topical), followed by anti-inflammatory and antispasmodic.
How Does Yarrow Work?
Yarrow works as a mixture rather than a single isolated compound, and its profile is usually described by the class of constituents present in aerial parts (flower, leaf) rather than by one marker molecule.
Before its chemistry was known, Yarrow was judged by what it did in the cup: how strongly it brewed, how it tasted, and how little or much was needed. Those notes are why particular preparations survived and others did not.
Published research is limited, leaning on small trials, laboratory work and animal models, and this profile cites 3 sources. Reported findings centre on traditional use extensively documented across cultures. Where research exists, it examines hemostatic — may stop minor bleeding (topical), anti-inflammatory and antispasmodic and traditional use for fever, colds, and digestive complaints. These are areas of study, not established outcomes, and results differ by preparation and dose.
How the plant is prepared changes what you actually get. Its constituents move readily into fixed oil — so a preparation made in another medium will not carry the same fraction of the plant, which is why traditional recipes specify one over another.
Yarrow is studied as a whole preparation because isolating one fraction tends to behave differently from the material it was taken out of — a recurring finding across the plant-chemistry literature.
Because these constituents are processed by the same pathways that handle many medicines, Yarrow is documented as interacting with anticoagulants, sedatives and antihypertensives. That is a question of shared metabolism rather than of potency, and it is the main reason the plant is listed in interaction references at all.
Dose, plant part and growing conditions all shift the constituent profile, so two products carrying the name Yarrow can differ substantially; this is why reference entries specify aerial parts (flower, leaf) and, where they exist, standardisation markers.