COMMON NAMES. Milfoil, Thousand Seal, Nose-bleed.
    MEDICINAL PART. The herb.
    Description. -- Yarrow, also called Thousand Seal, is from ten to twenty inches high, with a simple stem, branching at the top, and many long, crowded, alternate and dentate leaves spread upon the ground, finely cut, and divided into many parts. The flowers are white or rose-colored, and arrayed in knots upon divers green stalks, which arise from among the leaves. Fruit an oblong, flattened achenium.
    History. -- Yarrow inhabits Europe and North America; it is found in pastures, meadows, and along road-sides, flowering from May to October. The plant possesses a faint, pleasant, peculiar fragrance, and a rather sharp, rough astringent taste, which properties are due to tannic and achilleic acid, essential oil, and bitter extractive, alcohol or water being its proper menstruum.
    Properties and Uses. -- It is astringent, alterative, and diuretic, in decoction. It is efficacious in bleeding from the lungs and other hemorrhages, incontinence of urine, piles and dysentery. It is valuable in amenorrhoea, or suppressed or restrained menses, flatulency, and spasmodic diseases. It forms a useful injection in leucorrhoea or whites, also in menorrhagia, or profuse or too long continued menstruation. An ointment cures wounds, ulcers, fistulas, and the head bathed in a decoction prevents the falling out of the hair; while the leaves chewed in the mouth will frequently ease the toothache. ACHILLES is supposed to be the first that left the virtues of this herb to posterity, hence the active principle of this plant is called Achilleine, which is much used as a substitute for quinia in intermittent fevers in the South of Europe.
    Dose. -- The infusion of Yarrow is given in doses of from a wineglassful to a teacupful, three or four times a day; the essential oil from five to twenty drops. In menorrhagia or profuse menstruation, a tablespoonful of the saturated tincture may be given three or four times a day.
    Achillea Ptarmica or Sneese-wort, has leaves entirely different from the Yarrow, and should not be mistaken one for the other. The whole of this plant is pungent, exciting an increased flow of saliva; and the powder of the dried leaves, when snuffed into the nostrils, produces sneezing, which is supposed to be owing to their small, sharp, and marginal teeth.