This section is from the book "Botanic Drugs Their Materia Medica, Pharmacology and Therapeutics", by Thomas S. Blair. Also available from Amazon: Botanic Drugs, Their Materia Medica, Pharmacology and Therapeutics.
Canada Fleabane, Erigeron Canadense. The Oil of Erigeron was official in the eighth U. S. P., but is deleted from the ninth. The oil resembles oil of turpentine in effect (See "Abies" for details), but is less efficient, although less disagreeable to take internally. Average dose of the oil, 15 minims.
The fl. of erigeron is employed in the treatment of gastroenteric and genito-urinary disturbances marked by capillary hemorrhage and catarrhal exudates, as well as in the treatment of tympanites. Naturally, it is effective only in passive hemorrhage, and it is contraindicated in acute congestion of the kidneys. Dose: 10 to 60 minims.
If the oil were put up in soluble elastic capsules, it might be used in sufficient dosage to be effective. The fl. adds astringent properties (tannic and gallic acids) to the oil content. Small doses of neither one may be commended; but full dosage of erigeron or its oil often serves well when a terebinthinate is indicated.