Botanical name: 

The whole plant of Erigeron canadense, Linné (Nat. Ord. Compositae). A common and troublesome weed through the northern and central parts of the United States.
Common Names: Canada Fleabane, Colt's Tail, Pride Weed, Scabious.

Principal Constituents.—A volatile oil (Oleum Erigerontis), and tannic and gallic acids.
Preparations.—1. Specific Medicine Erigeron. Dose, 1 to 60 drops.
2. Oleum Erigerontis, Oil of Erigeron. Dose, 5 to 30 minims, on sugar.

Specific Indications.—(Oil) capillary or passive hemorrhages, hematuria, hemoptysis, epistaxis, hematemesis, and metrorrhagia; "painful diseases of the kidneys and bladder, and in diseases of the mucous membranes attended by free discharges" (Scudder). Infusion, choleraic discharges, sudden, gushing, and watery, attended with thirst and cramping pain, and sometimes streaked with blood.

Action and Therapy.—Erigeron restrains excessive bowel and kidney discharges. An infusion is a deservedly popular remedy for profuse summer diarrheas of infants, especially that of cholera infantum and gastroenteritis. It is indicated by the suddenly gushing and copious evacuations, with cramps, or with but little pain, but often with the presence of slight amounts of blood. The infusion is better than alcoholic preparations for these purposes; besides it supplies water to take the place of the natural fluids so greatly depleted by the discharges. It is also useful in dysentery with passages of mucus and blood. As a remedy for slight hemorrhages, as from the bowels and kidneys, it is rather weak, but sometimes effectual; the oil is a much surer acting hemostatic. Both may be used as a diuretic in gravelly conditions as well as in chronic nephritis, when the urine is tinged with blood, or even where passive hemorrhage is present. It has restrained the pathologic flow of urine in polyuria, or so-called diabetes insipidus.

The oil of erigeron is a good internal hemostatic. It sometimes checks quite severe uterine hemorrhages, and for very small oozings of blood it is one of the very best agents to control the flow. It is also indicated in epistaxis and moderate bleeding from the stomach, bowels, and kidneys. Given in syrup it is useful as a cough medicine when there is bloody expectoration.

The Eclectic Materia Medica, Pharmacology and Therapeutics, 1922, was written by Harvey Wickes Felter, M.D.