From King's American Dispensatory
History and Description.—This is an indigenous, rank weed, growing in fields throughout the United States, in moist woods, and in recent clearings, especially and abundantly in such as have been burned over, hence its vernacular name Fireweed. It flowers from August to October, and resembles in appearance the sow-thistle (Sonchus oleraceus); the flowers somewhat resemble those of lettuce. The whole plant is medicinal, and yields its virtues to water or alcohol. The leaves, which are most generally employed, when dried are almost black, and by this characteristic, as well as by form, may be distinguished from those of Erigeron canadense, or Erigeron annuum, with which they are sometimes confused.
Action, Medical Uses, and Dosage.—Fireweed is reputed to be emetic, cathartic, tonic, astringent, and alterative, of which the most valuable are the latter three. Reputed an unrivaled medicine in diseases of the mucous tissues of the lungs, stomach, and bowels.