Horsetail Plant

A genus of 29 species of spore-bearing perennials that occurs worldwide (except Australia) in cool, damp places. Horsetails have barely changed since prehistoric times, when they formed a large part of the vegetation that decomposed to form coal seams. Some species are pernicious weeds. Once they have produced the cone-like heads from which the spores are shed, the fertile stems die and are replaced by sterile ones. Horsetails have an unusual chemistry, containing alkaloids (including nicotine), and various minerals. They are rich in silica, giving abrasive properties that were used from the Middle Ages until the 18th century for scouring pots and pans, especially pewter. The Dutch rush (Equisetum hyemale) was once exported from the Netherlands, where it grows abundantly, for this purpose. Certain horsetails concentrate gold in their tissues (although not sufficient to warrant extraction) and are useful indicators for gold prospectors.

Horsetail is so named because its jointed stems produce bristly leaves that resemble a horse's tail. The stems of the horsetail plant contain such high concentrations of silica that they have been used for polishing metal, especially pewter. Horsetail tea, high in organic silicon concentrations, has been used to strengthen connective tissue, fight arthritis, treat urinary tract infections, promote bone and cartilage formation, and revive brittle nails and lifeless hair.

Herbasceous perennial with a hairy, tuberous rhizome. Erect, often branched, sterile stems have black tooth-like sheaths and whorls of spreading, green branches. Spores ripen in spring.

Common Name:
Horsetail Plant
Other Names:
Bottle Brush, Chevalier, Horsetail, Field Horsetail, Horsetail Rush, Horse Willow, Pewterwort, Shave Grass
Botanical Name:
Equisetum arvense
Europe to C China, N America, and Greenland
Moist soil in sun or partial shade. Horsetails are invasive and difficult to irradicate, Equisetum species are subject to statuatory control as a weed in parts of Australia.
By seed sown when ripe; by division after flowering, or in autumn; by rhizome sections in warmth in winter.
Stems are cut at any time during the growing season and dried for use in decoctions, infusions, liquid extracts, and powders.
20-80cm (8-32in)
One of the oldest of the plant kingdom's herbs—it can be traced back to the time of the dinosaurs—horsetail has a long history of commercial and medicinal use.  In Europe, from medieval times through the late eighteenth century, the distinctive "tails" of the plant were used to scrub pots and pans and to polish pewter and brass.  In the New World, Native Americans and Mexicans used it for the same purposes, as well as to polish hardwoods.  Medicinally, it has been used since ancient times to staunch bleeding, bind up damaged bones and skin tissue, relieve water retention, and, according to seventeenth-century herbalist Nicholas Culpeper, to reduce heat and inflammation in the "privy parts" of men and women.
Parts Used:
Above ground parts,  Leaves, Stems
An astringent, healing herb that acts mainly on the genito-urinary system and controls both internal and external bleeding.
Vitamin Content:
Vitamin A
Medicinal Uses:
Internally for prostatitis, incontinence, cystitis, and urethritis. Often used with Hydrangea arborescens (See, Wild Hydrangea) for prostate problems. Internally and externally for hemorrhage. An irritant, best combined with demulcent herbs, and restricted to short term use.
To treat kidney stones, rheumatic disease, gout, brittle fingernails, loss of hair, frostbite, ulcers, and wounds. Germany's Commission E has approved the use of horsetail to treat urinary tract infections, kidney and bladder stones, wounds, and burns.
Horsetail is rich in a chemical called silica, which helps repair broken bones and sprained muscles, heal damaged connective tissue, and stimulate the production of collagen, a key component of healthy bones and tissue.  Modern herbalists prescribe horsetail to stop external bleeding, repair broken bones or sprains; strengthen bones (as a prevention against osteoporosis); treat the pain and tissue damage associated with rheumatism, arthritis, and other connective tissue ailments; increase urine output; and relieve the symptoms of benign prostate ailments.  Horsetail also strengthens hair and nails.
Typical Dose:
A typical daily dose of horsetail is approximately 6 gm of the herb, taken with plenty of fluids.
Horsetail is available as fresh and dried herb and in teas and tinctures. To make a tea, pour 1 cup of boiling water over 1 teaspoon of dried herb, or 2 teaspoons of fresh herb, and steep for 15 minutes. Strain and allow to cool. Drink cold, 2 tablespoons at a time, up to 3 cups a day.
Use horsetail for short-term use only, under the guidance of a qualified practitioner and at prescribed doses. Extended use or higher-than-prescribed doses may cause kidney or heart damage. Mild side effects may include stomach upset, excessive urination, and diarrhea. More serious side effects may include kidney pain, lower back pain, and painful urination. Consult your doctor if you have any of these side effects.
Possible Side Effects:
Horsetail's more common side effects when taken internally include thiamin deficiency. Used externally, it may cause seborrheic dermatitis.
Drug Interactions:
Taking horsetail with these drugs may increase the risk of hypokalemia (low levels of potassium in the blood):
Acetazolamide, (Apo-Acetazolamide, Diamox Sequels)
Azosemide, (Diat)
Bumetanide, (Bumex, Burinex)
Chlorothiazide, (Diuril)
Chlorthalidone, (Apo-Chlorthalidone, Thalitone)
Ethacrynic Acid, (Edecrin)
Etozolin, (Elkapin)
Furosemide, (Apo-Furosemide, Lasix)
Hydrochlorothiazide, (Apo-Hydro, Microzide)
Hydroflumethiazide, (Diucardin, Saluron)
Indapamide, (Lozol, Nu-Indapamide)
Mannitol, (Osmitrol, Resectisol)
Mefruside, (Baycaron)
Methazolamide, (Apo-Methazolamide, Neptazane)
Methyclothiazide, (Aquatensen, Enduron)
Metolazone, (Mykrox, Zaroxolyn)
Olmesartan and Hydrochlorothiazide, (Benicar HCT)
Polythiazide, (Renese)
Torsemide, (Demadex)
Trichlormethiazide, (Metatensin, Naqua)
Urea, (Amino-Cerv, UltraMide)
Xipamide, (Diurexan, Lumitens)
Taking horsetail with these drugs may increase the risk of drug toxicity:
Digitalis, (Digitek, Lanoxin)
Lithium, (Carbolith, Eskalith)
Taking horsetail with these drugs may increase stimulation of the central nervous system:
Caffeine-Containing Drugs, (such as Alka-Seltzer Morning Relief Tablets, Cafergot, Excedrin Extra-Strength)
Theophylline, (Elixophyllin, Uniphyl)
Disease Effects:
May harm heart and kidney function by encouraging the secretion of too much potassium.
Food Interactions:
  • May cause increased central nervous system stimulation when used with caffeinated beverages such as coffee or tea.
  • May break down thiamin (vitamin B1), increasing the risk of thiamin deficiency.
  • Increased risk of chromium toxicity when taken with chromium supplements due to chromium content of horsetail.
  • Increased central nervous system stimulation when used with tobacco or nicotine.
Supplement Interactions:
Encyclopedia of Herbs by Deni BrownCopyright © 1995, 2001 Dorling Kindersley Limited. pp. 203
The Essential Herb-Drug-Vitamin Interaction Guide by Geo. T. Grossberg,MD and Barry Fox,PhD Copyright©2007 Barry Fox,PhD. Pp.277-279
The Modern Herbal Primer by Nancy Burke Copyright©2000 Yankee Publishing, Inc. pg 14.