Common names: Bottlebrush plant, Shave grass, Scouring rush
Botanical name: Equisetum arvense
© Steven Foster
Parts used and where grown
Horsetail is widely distributed throughout the temperate climate zones of the Northern
Hemisphere, including Asia, North America, and Europe.1 Horsetail is a unique plant
with two distinctive types of stems. One variety of stem grows early in spring and looks like
asparagus, except for its brown color and spore-containing cones on top. The mature form of
the herb, appearing in summer, has branched, thin, green, sterile stems and looks like a
Horsetail has been used in
connection with the following conditions (refer to the individual
health concern for complete information):
Historical or traditional use (may
or may not be supported by scientific studies)
Reportedly first recommended by the Roman physician Galen, several cultures have employed
horsetail as a folk remedy for kidney and bladder troubles, arthritis, bleeding ulcers, and
tuberculosis. In addition, the topical use of horsetail was used traditionally to stop the
bleeding of wounds and promote rapid healing. The use of this herb as an abrasive cleanser to
scour pots or shave wood illustrates the origin of horsetail’s common
names—scouring rush and shave grass.2
Horsetail is rich in silicic acid and silicates, which provide approximately 2–3%
elemental silicon. Potassium, aluminum, and manganese, along with fifteen different types of flavonoids, are also found in this herb. The
presence of these flavonoids, as well as saponins, is believed to cause the diuretic effect,
while the silicon content is thought to exert a connective tissue-strengthening and
anti-arthritic action.3 Some experts have suggested the element silicon in
horsetail is also a vital component for bone and cartilage formation.4 Anecdotal
reports suggest that horsetail may be of some use in the treatment of brittle nails.5
How much is usually taken?
The German Commission E monograph suggests up to 6 grams of the herb per day for internal
use.6 A tincture can also be used at 2 teaspoons (10 ml) three times per day. A
horsetail tea may be made by boiling 2–4 teaspoons of the herb in one cup (250 ml) of
water for five minutes. Steep the tea for an additional 15 minutes, strain, and drink two or
three times daily. The tea can also be used externally as well as internally.
Are there any side effects or interactions?
Horsetail is generally considered safe. The only concern would be that the correct species
of horsetail is used. Equisetum palustre is another species of horsetail, which
contains toxic alkaloids and is a well-known livestock poison. Due to a lack of clear safety
information, horsetail should be avoided during
pregnancy and breast-feeding.
The Canadian Health Protection Branch requires supplement manufacturers to document that
their products do not contain the enzyme thiaminase, found in crude horsetail, which destroys
the B vitamin thiamine. Since alcohol,
temperature, and alkalinity neutralize this potentially harmful enzyme, tinctures, fluid
extracts, or preparations of the herb subjected to 100°C temperatures during
manufacturing are preferred for medicinal use.7
Are there any drug
Certain medicines may interact with horsetail. Refer to drug interactions for a list of those medicines.
1. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients
Used in Foods, Drugs, and Cosmetics, 2nd ed. New York: John Wiley & Sons, 1996,
2. Castleman M. The Healing Herbs. Emmaus, PA: Rodale Press,
3. Weiss RF. Herbal Medicine. Gothenburg Sweden: Ab Arcanum,
4. Seaborn CD, Nielsen FH. Silicon: a nutritional beneficence for bones,
brains and blood vessels? Nutr Today 1993;28:13–8.
5. Hamon NW, Awang DVC. Horsetail. Canadian Pharm J
6. Blumenthal M, Busse WR, Goldberg A, et al. (eds). The Complete
Commission E Monographs: Therapeutic Guide to Herbal Medicines. Boston, MA: Integrative
Medicine Communications, 1998, 150–1.
7. Fabre B, Geay B, Beaufils P. Thiaminase activity in Equisetum
arvense and its extracts. Plant Med Phytother 1993;26:190–7.