Botanical name: 

The plant, Equisetum hyemale, Linné (Nat. Ord. Equisetaceae). A peculiar leafless plant found throughout the northern and western parts of the United States in damp and wet situations. Dose, 5 to 60 grains.
Common Names: Scouring Rush, Horse Tail, Shave Grass.

Principal Constituents.—A large amount of silica, a soft green resin, and equisetic acid (aconitic acid).
Preparation.—1. Specific Medicine Equisetum. Dose, 5 to 60 drops.
2. Infusum Equiseti. Infusion of Equisetum. Dose, 1 to 2 fluidounces.

Specific Indications.—Cystic irritation; tenesmic urging to urinate; nocturnal urinal incontinence; renal calculi.

Action and Therapy.—Equisetum is diuretic and astringent. It is asserted to greatly relieve irritation due to the presence of gravel and the tenesmic urging to urinate in acute inflammations of the genito-renal tract. When the bladder becomes so irritable that the patient, upon dropping to sleep, loses control over the urine it is said to be specially serviceable. It has restrained hematuria and is of service in acute prostatitis and in the prostatorrhea which follows it. The infusion (1 ounce to Water, 16 fluidounces) is the preferred preparation.

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