Yarrow (Achillea millefolium) is a flowering plant commonly used as a medicinal herb and in herbal teas. Yarrow is common throughout North America, Asia and Europe. Yarrow is also commonly known as nosebleed plant, old man's pepper, sanguinary, soldier's woundwort, thousand leaf, and devil's nettle. Historically it was used medicinally to slow the flow of blood from wounds.