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Horsetail (Equisetum arvense L.)

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Horsetail (Equisetum arvense L.)


Horsetail (Equisetum arvense) has traditionally been used in Europe as an oral diuretic for the treatment of edema. The German Commission E expert panel has approved horsetail for this indication. Horsetail is also occasionally used for osteoporosis, nephrolithiasis, urinary tract inflammation, and wound healing (topical). These uses have largely been based on anecdote and clinical tradition, rather than scientific evidence.

There is preliminary human evidence supporting the use of horsetail as a diuretic. One poorly designed human trial found horsetail to effectively raise bone density equally to calcium supplements.

In theory (based on mechanism of action), horsetail ingestion in large amounts may cause thiamine deficiency, hypokalemia, or nicotine toxicity. Reported adverse effects include dermatitis.


Bottle brush, cola de caballo, common horsetail, common scouring rush, corncob plant, corn horsetail, Dutch rush, field horsetail, horse willow, horsetail grass, horsetail rush, mokuzoku, mokchok, muzei ( E. hymale ), paddock pipes, pewterwort, prele, pribes des champs, running clubmoss, Schachtelhalm, scouring rush, Shenjincao, shave grass, toadpipe, Wenjing, Zinnkraut.

Crude drugs derived from Equisetum arvense include Wenjing, Jiejiecao, and Bitoucai.

Note : Equisetum arvense should not be confused with members of the genus Laminaria, kelp, or brown alga, for which "horsetail" has been used as a synonym.


These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Uses based on scientific evidenceGrade*Diuresis (increased urine)
Use of horsetail dates to ancient Roman and Greek medicine. The name Equisetum is derived from equus, "horse" and seta, "bristle." Preliminary human and laboratory research suggests that horsetail may increase the amount of urine produced by the body. More studies are needed to determine if horsetail is safe or useful for specific health conditions.


Osteoporosis (weakening of the bones)
Silicon may be beneficial for bone strengthening. Because horsetail contains silicon, it has been suggested as a possible natural treatment for osteoporosis. Preliminary human study reports benefits, but more detailed research is needed before a firm recommendation can be made. People with osteoporosis should speak with a qualified healthcare provider about possible treatment with more proven therapies.


* Key to grades
Strong scientific evidence for this use;
Good scientific evidence for this use;
Unclear scientific evidence for this use;
Fair scientific evidence against this use (it may not work);
Strong scientific evidence against this use (it likely does not work).

Uses based on tradition or theory
The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Antibacterial, antioxidant, astringent, bladder disturbances, bleeding, brittle fingernails, cancer, cosmetics, cystic ulcers, diabetes, dropsy, fever, fluid in the lungs, frostbite, gonorrhea, gout, hair loss, itch, kidney disease, kidney stones, leg swelling, liver protection, malaria, menstrual pain, nosebleeds, prostate inflammation, styptic (to stop bleeding cuts on the skin), Reiter's syndrome, rheumatism, stomach upset, thyroid disorders, tuberculosis, urinary incontinence, urinary tract infection (UTI), urinary tract inflammation, wound healing.


The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.


Standardization involves measuring the amount of certain chemicals in products to try to make different preparations similar to each other. It is not always known if the chemicals being measured are the "active" ingredients. There is no widely recognized standardization for horsetail products. Standardization may be difficult, as approximately 25 species of Equisetum exist, and it is often difficult to differentiate between species. In Europe, the silicon content in horsetail may be less than 15%. Some experts recommend that horsetail should be standardized to 10% silicon per dose.

Adults (18 years and older)

Recommended doses for horsetail are based on historical use or expert opinion. There are no reliable studies in humans that show horsetail to be effective or safe at any specific dose.

By Mouth :

Tablets/Capsules : Different doses have been used, starting at 300 milligram capsules taken three times per day, up to 6 grams per day.

Tea : A maximum of 6 cups of tea, containing 1.5 grams of dried stem in one cup of hot water, is a dose that has been used.

Tincture (1:1 in 25% alcohol) : 1 to 4 milliliters three times daily has been used.

Applied to the skin :

External wash : A wash prepared by mixing 10 teaspoons of horsetail in cold water and soaking for 10 to 12 hours has been used.

Children (younger than 18 years)

There is not enough scientific information to recommend the use of horsetail in children. Poisonings have been reported in children using horsetail stems as whistles.


The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.


People with allergies to E. arvense, related substances, or to nicotine should avoid horsetail. Rash has been reported in a patient taking horsetail who was known to be sensitive to nicotine.

Side Effects and Warnings

There are few scientific studies or reports of side effects with horsetail. It is more often used in Germany and Canada, where it is traditionally considered to be safe when taken in appropriate doses. E. palustre (marsh horsetail) contains a poisonous ingredient and should be avoided. There are reports that some batches of E. arvense (horsetail) have been contaminated with E. palustre .

Large doses of horsetail may cause symptoms of nicotine overdose, including fever, cold hands and feet, abnormal heart rate, difficulty walking, muscle weakness, and weight loss. People who smoke or who use nicotine patches or nicotine gum should avoid horsetail. Reports from animal studies and one report of a nicotine-allergic person describe a rash occurring after the use of white horsetail. Other reports from use in animals describe nausea, increased frequency of bowel movements, increased urination, loss of the body's potassium stores, and muscle weakness. People with kidney disorders should avoid horsetail.

Studies in mice suggest that horsetail may change the activity of the kidneys, causing abnormal control of the amount of water and potassium release. Low potassium, which in theory may occur with horsetail, can have negative effects on the heart. Individuals who have heart rhythm disorders or who take digoxin should be cautious. Studies suggest that horsetail does not change blood pressure. Other horsetail species have caused low blood sugar.

Horsetail contains an ingredient that destroys thiamine (vitamin B1), which could lead to deficiency with long-term use. This may cause permanent damage to the brain and nervous system, including confusion, difficulty walking, difficulties with vision and eye movement, and memory loss. People who have thiamine (vitamin B1) deficiency or poor nutrition should avoid horsetail, as it may affect levels of thiamine even more. Alcoholic or malnourished individuals are often thiamine deficient and this may be worsened by horsetail.

Avoid use in children due to anecdotal reports of poisonings while using horsetail stems as whistles.

Pregnancy and Breastfeeding

Horsetail is not recommended during pregnancy or breastfeeding, since little information is available about its safety. Its potential to cause thiamine (vitamin B1) depletion, low potassium, and nicotine-like effects are of particular concern. Many tinctures contain high levels of alcohol, and should be avoided during pregnancy.


1. Corletto F. [Female climacteric osteoporosis therapy with titrated horsetail (Equisetum arvense) extract plus calcium (osteosil calcium): randomized double blind study]. Miner Ortoped Traumatol 1999;50:201-206.

2. Fabre B, Geay B, Beaufils P. Thiaminase activity in and its extracts. Plant Med Phytother 1993;26:190-197.

3. Gibelli C. The hemostatic action of Equisetum. Arch Intern Pharmacodynam 1931;41:419-429.

4. Graefe EU, Veit M. Urinary metabolites of flavonoids and hydroxycinnamic acids in humans after application of a crude extract from Equisetum arvense. Phytomedicine. 1999 Oct;6(4):239-46.

5. Henderson JA, Evans EV, McIntosh RA. The antithiamine action of Equisetum. J Amer Vet Med Assoc 1952;120:375-378.

6. Joksic G, Stankovic M, Novak A. Antibacterial medicinal plants Equiseti herba and Ononidis radix modulate micronucleus formation in human lymphocytes in vitro. J Environ Pathol Toxicol Oncol. 2003;22(1):41-8.

7. Katikova OIu, Kostin IaV, Tishkin VS. Hepatoprotective effect of plant preparations [Article in Russian]. Eksp Klin Farmakol. 2002 Jan-Feb;65(1):41-3.

8. Maeda H, Miyamoto K, Sano T. Occurrence of dermatitis in rats fed a cholesterol diet containing field horsetail (Equisetum arvense L.). J Nutr Sci Vitaminol (Tokyo). 1997 Oct;43(5):553-63.

9. Nitta A, Yoshida S, Tagaeto T. A comparative study of crude drugs in Southeast Asia. X. Crude drugs derived from Equisetum species. Chem Pharm Bull (Tokyo) 1977;25(5):1135-1139.

10. Perez Gutierrez RM, Laguna GY, Walkowski A. Diuretic activity of Mexican equisetum. J Ethnopharmacol 1985;14 (2-3) :269-272.

11. Revilla MC, Andrade-Cetto A, Islas S, Wiedenfeld H. Hypoglycemic effect of Equisetum myriochaetum aerial parts on type 2 diabetic patients. J Ethnopharmacol. 2002 Jun;81(1):117-20.

12. Sudan BJ. Seborrhoeic dermatitis induced by nicotine of horsetails ( L.). Contact Dermatitis 1985;13(3):201-202.

13. Tiktinskii OL, Bablumian IuA. Therapeutic action of Java tea and field horsetail in uric acid diathesis [Article in Russian]. Urol Nefrol (Mosk). 1983 Jan-Feb;(1):47-50.

January 01, 2004

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