URL of this page: https://medlineplus.gov/druginfo/natural/843.html

Horsetail

What is it?

Horsetail is a plant. The above ground parts are used to make medicine.

People use horsetail for "fluid retention" (edema), urinary tract infections, loss of bladder control (urinary incontinence), wounds, and many other conditions, but there is no good scientific evidence to support these uses. Using horsetail can also be unsafe.

Horsetail is sometimes used in cosmetics and shampoos.

How effective is it?

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.

The effectiveness ratings for HORSETAIL are as follows:

Insufficient evidence to rate effectiveness for...

  • Weak and brittle bones (osteoporosis). Early research suggests that taking dry horsetail extract or a specific product containing horsetail extract and calcium can increase bone density in postmenopausal women with osteoporosis.
  • Loss of bladder control (urinary incontinence).Early research shows that taking a supplement containing horsetail and other herbs helps to reduce urination and loss of bladder control in people that have trouble controlling their bladder.
  • Fluid retention.
  • Frostbite.
  • Gout.
  • Hair loss.
  • Heavy periods.
  • Kidney and bladder stones.
  • Swelling (inflammation) of the tonsils (tonsillitis).
  • Urinary tract infections.
  • Use on the skin for wound healing.
  • Weight loss.
  • Other conditions.
More evidence is needed to rate the effectiveness of horsetail for these uses.

How does it work?

The chemicals in horsetail may have antioxidant and anti-inflammatory effects. Horsetail contains chemicals that work like "water pills" (diuretics) and increase urine output.

Are there safety concerns?

When taken by mouth: Horsetail is POSSIBLY UNSAFE when taken by mouth, long-term. It contains a chemical called thiaminase, which breaks down the vitamin thiamine. In theory, this effect could lead to thiamine deficiency. Some products are labeled "thiaminase-free," but there is not enough reliable information to know if these products are safe.

When applied to the skin: There isn't enough reliable information to know if horsetail is safe or what the side effects might be.

Special precautions & warnings:

Pregnancy and breast-feeding: There isn't enough reliable information to know if horsetail is safe to use when pregnant or breast-feeding. Stay on the safe side and avoid use.

Alcoholism: People who are alcoholics are generally also thiamine deficient. Taking horsetail might make thiamine deficiency worse.

Allergies to carrots and nicotine: Some people with allergy to carrot might also have allergy to horsetail. Horsetail also contains small amounts of nicotine. People with nicotine allergy might have an allergic reaction to horsetail.

Diabetes: Horsetail might lower blood sugar levels in people with diabetes. Watch for signs of low blood sugar (hypoglycemia) and monitor your blood sugar carefully if you have diabetes and use horsetail.

Low potassium levels (hypokalemia): There is some concern that horsetail might flush potassium out of the body, possibly leading to potassium levels that are too low. Until more is known, use horsetail with caution if you are at risk for potassium deficiency.

Low thiamine levels (thiamine deficiency): Taking horsetail might make thiamine deficiency worse.

Are there interactions with medications?

Moderate
Be cautious with this combination.
Efavirenz (Sustiva)
Efavirenz (Sustiva) is a drug used to treat HIV. Taking horsetail with efavirenz might reduce the effects of efavirenz. Talk with your healthcare provider before using horsetail if you are taking efavirenz.
Lithium
Horsetail might have an effect like a water pill or "diuretic." Taking horsetail might decrease how well the body gets rid of lithium. This could increase how much lithium is in the body and result in serious side effects. Talk with your healthcare provider before using this product if you are taking lithium. Your lithium dose might need to be changed.
Medications for diabetes (Antidiabetes drugs)
Horsetail might decrease blood sugar in people with type 2 diabetes. Diabetes medications are also used to lower blood sugar. Taking horsetail along with diabetes medications might cause your blood sugar to go too low. Monitor your blood sugar closely. The dose of your diabetes medication might need to be changed.

Some medications used for diabetes include glimepiride (Amaryl), glyburide (DiaBeta, Glynase PresTab, Micronase), insulin, pioglitazone (Actos), rosiglitazone (Avandia), chlorpropamide (Diabinese), glipizide (Glucotrol), tolbutamide (Orinase), and others.
Medications for HIV/AIDS (Nucleoside reverse transcriptase inhibitors (NRTIs))
Nucleoside reverse transcriptase inhibitors (NRTIs) are used to treat HIV. Taking horsetail with NRTIs might reduce the effects of these drugs. Talk with your healthcare provider before using horsetail if you are taking an NRTI. Some NRTIs include emtricitabine, lamivudine, tenofovir, and zidovudine.
Water pills (Diuretic drugs)
"Water pills" can decrease potassium levels in the body. Taking large amounts of horsetail might also decrease potassium levels in the body if used long-term. Taking horsetail along with "water pills" might decrease potassium in the body too much.

Some "water pills" that can deplete potassium include chlorothiazide (Diuril), chlorthalidone (Thalitone), furosemide (Lasix), hydrochlorothiazide (HCTZ, HydroDiuril, Microzide), and others.

Are there interactions with herbs and supplements?

Betel nut
Horsetail and betel nut both reduce the amount of thiamine that the body has to use. Using these herbs together raises the risk that the amount of thiamine will become too low.
Chromium-containing herbs and supplements
Horsetail contains chromium (0.0006%) and could increase the risk of chromium poisoning when taken with chromium supplements or chromium-containing herbs such as bilberry, brewer's yeast, or cascara.
Herbs and supplements that might lower blood sugar
Horsetail might lower blood sugar. Using it along with other herbs and supplements that have the same effect might cause blood sugar to drop too low in some people. Some of these products include alpha-lipoic acid, bitter melon, chromium, devil's claw, fenugreek, garlic, guar gum, horse chestnut, Panax ginseng, psyllium, Siberian ginseng, and others.
Thiamine
Crude horsetail contains thiaminase, a chemical that breaks down thiamine. Taking horsetail might cause thiamine deficiency.

Are there interactions with foods?

There are no known interactions with foods.

What dose is used?

The appropriate dose of horsetail depends on several factors such as the user's age, health, and several other conditions. At this time there is not enough scientific information to determine an appropriate range of doses for horsetail. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult your pharmacist or physician or other healthcare professional before using.

Other names

Asprêle, Bottle Brush, Cavalinha, Coda Cavallina, Cola de Caballo, Common Horsetail, Corn Horsetail, Dutch Rushes, Equiseti Herba, Equisetum, Equisetum arvense, Equisetum giganteum, Equisetum myriochaetum, Equisetum hyemale, Equisetum telmateia, Field Horsetail, Giant Horsetail, Great Horsetail, Herba Equiseti, Herbe à Récurer, Horse Herb, Horsetail Grass, Horsetail Rush, Horse Willow, Paddock-Pipes, Pewterwort, Prele, Prêle, Prêle Commune, Prêle des Champs, Puzzlegrass, Scouring Rush, Souring Rush, Shave Grass, Shavegrass, Snake Grass, Spring Horsetail, Toadpipe.

Methodology

To learn more about how this article was written, please see the Natural Medicines Comprehensive Database methodology.

References

  1. Popovych V, Koshel I, Malofiichuk A, et al. A randomized, open-label, multicenter, comparative study of therapeutic efficacy, safety and tolerability of BNO 1030 extract, containing marshmallow root, chamomile flowers, horsetail herb, walnut leaves, yarrow herb, oak bark, dandelion herb in the treatment of acute non-bacterial tonsillitis in children aged 6 to 18?years. Am J Otolaryngol. 2019;40:265-273. View abstract.
  2. Schoendorfer N, Sharp N, Seipel T, Schauss AG, Ahuja KDK. Urox containing concentrated extracts of Crataeva nurvala stem bark, Equisetum arvense stem and Lindera aggregata root, in the treatment of symptoms of overactive bladder and urinary incontinence: a phase 2, randomised, double-blind placebo controlled trial. BMC Complement Altern Med. 2018;18:42. View abstract.
  3. García Gavilán MD, Moreno García AM, Rosales Zabal JM, Navarro Jarabo JM, Sánchez Cantos A. Case of drug-induced acute pancreatitis produced by horsetail infusions. Rev Esp Enferm Dig. 2017 Apr;109:301-304. View abstract.
  4. Cordova E, Morganti L, Rodriguez C. Possible Drug-Herb Interaction between Herbal Supplement Containing Horsetail (Equisetum arvense) and Antiretroviral Drugs. J Int Assoc Provid AIDS Care. 2017;16:11-13. View abstract.
  5. Radojevic ID, Stankovic MS, Stefanovic OD, Topuzovic MD, Comic LR, Ostojic AM. Great horsetail (Equisetum telmateia Ehrh.): Active substances content and biological effects. EXCLI J. 2012 Feb 24;11:59-67. View abstract.
  6. Ortega García JA, Angulo MG, Sobrino-Najul EJ, Soldin OP, Mira AP, Martínez-Salcedo E, Claudio L. Prenatal exposure of a girl with autism spectrum disorder to 'horsetail' (Equisetum arvense) herbal remedy and alcohol: a case report. J Med Case Rep. 2011 Mar 31;5:129. View abstract.
  7. Klnçalp S, Ekiz F, Basar Ö, Coban S, Yüksel O. Equisetum arvense (Field Horsetail)-induced liver injury. Eur J Gastroenterol Hepatol. 2012 Feb;24:213-4. View abstract.
  8. Gründemann C, Lengen K, Sauer B, Garcia-Käufer M, Zehl M, Huber R. Equisetum arvense (common horsetail) modulates the function of inflammatory immunocompetent cells. BMC Complement Altern Med. 2014 Aug 4;14:283. View abstract.
  9. Farinon M, Lora PS, Francescato LN, Bassani VL, Henriques AT, Xavier RM, de Oliveira PG. Effect of Aqueous Extract of Giant Horsetail (Equisetum giganteum L.) in Antigen-Induced Arthritis. Open Rheumatol J. 2013 Dec 30;7:129-33. View abstract.
  10. Carneiro DM, Freire RC, Honório TC, Zoghaib I, Cardoso FF, Tresvenzol LM, de Paula JR, Sousa AL, Jardim PC, da Cunha LC. Randomized, Double-Blind Clinical Trial to Assess the Acute Diuretic Effect of Equisetum arvense (Field Horsetail) in Healthy Volunteers. Evid Based Complement Alternat Med. 2014;2014:760683. View abstract.
  11. Henderson JA, Evans EV, and McIntosh RA. The antithiamine action of Equisetum. J Amer Vet Med Assoc 1952;120:375-378.
  12. 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.
  13. Tiktinskii, O. L. and Bablumian, I. A. [Therapeutic action of Java tea and field horsetail in uric acid diathesis]. Urol.Nefrol.(Mosk) 1983;3:47-50. View abstract.
  14. Graefe, E. U. and Veit, M. Urinary metabolites of flavonoids and hydroxycinnamic acids in humans after application of a crude extract from Equisetum arvense. Phytomedicine 1999;6:239-246. View abstract.
  15. Agustin-Ubide MP, Martinez-Cocera C, Alonso-Llamazares A, et al. Diagnostic approach to anaphylaxis by carrot, related vegetables and horsetail (Equisetum arvense) in a homemaker. Allergy 2004;59:786-7. View abstract.
  16. Revilla MC, Andrade-Cetto A, Islas S, Wiedenfeld H. Hypoglycemic effect of Equisetum myriochaetum aerial parts on type 2 diabetic patients. J Ethnopharmacol 2002;81:117-20. View abstract.
  17. Lemus I, Garcia R, Erazo S, et al. Diuretic activity of an Equisetum bogotense tea (Platero herb): evaluation in healthy volunteers. J Ethnopharmacol 1996;54:55-8. View abstract.
  18. Perez Gutierrez RM, Laguna GY, Walkowski A. Diuretic activity of Mexican equisetum. J Ethnopharmacol 1985;14:269-72. View abstract.
  19. Fabre B, Geay B, Beaufils P. Thiaminase activity in equisetum arvense and its extracts. Plant Med Phytother 1993;26:190-7.
  20. Henderson JA, Evans EV, McIntosh RA. The antithiamine action of Equisetum. J Am Vet Med Assoc 1952;120:375-8. View abstract.
  21. Ramos JJ, Ferrer LM, Garcia L, et al. Polioencephalomalacia in adult sheep grazing pastures with prostrate pigweed. Can Vet J 2005;46:59-61. View abstract.
  22. Husson GP, Vilagines R, Delaveau P. [Antiviral properties of various extracts of natural origin]. Ann Pharm Fr 1986; 44:41-8. View abstract.
  23. Do Monte FH, dos Santos JG Jr, Russi M, et al. Antinociceptive and anti-inflammatory properties of the hydroalcoholic extract of stems from Equisetum arvense L. in mice. Pharmacol Res 2004;49:239-43. View abstract.
  24. Correia H, Gonzalez-Paramas A, Amaral MT, et al. Characterisation of polyphenols by HPLC-PAD-ESI/MS and antioxidant activity in Equisetum telmateia. Phytochem Anal 2005;16:380-7. View abstract.
  25. Langhammer L, Blaszkiewitz K, Kotzorek I. Evidence of toxic adulteration of equisetum. Dtsch Apoth Ztg 1972;112:1751-94.
  26. Dos Santos JG Jr, Blanco MM, Do Monte FH, et al. Sedative and anticonvulsant effects of hydroalcoholic extract of Equisetum arvense. Fitoterapia 2005;76:508-13. View abstract.
  27. Sakurai N, Iizuka T, Nakayama S, et al. [Vasorelaxant activity of caffeic acid derivatives from Cichorium intybus and Equisetum arvense]. Yakugaku Zasshi 2003;123:593-8. View abstract.
  28. Oh H, Kim DH, Cho JH, Kim YC. Hepatoprotective and free radical scavenging activities of phenolic petrosins and flavonoids isolated from Equisetum arvense. J Ethnopharmacol 2004;95:421-4.. View abstract.
  29. Sudan BJ. Seborrhoeic dermatitis induced by nicotine of horsetails (Equisetum arvense L.). Contact Dermatitis 1985;13:201-2. View abstract.
  30. Piekos R, Paslawska S. Studies on the optimum conditions of extraction of silicon species from plants with water. I. Equisetum arvense L. Herb. Planta Med 1975;27:145-50. View abstract.
  31. Health Canada. Labelling Standard: Mineral Supplements. Available at: http://www.hc-sc.gc.ca/dhp-mps/prodpharma/applic-demande/guide-ld/label-etiquet-pharm/minsup_e.html (Accessed 14 November 2005).
  32. Vimokesant S, Kunjara S, Rungruangsak K, et al. Beriberi caused by antithiamin factors in food and its prevention. Ann N Y Acad Sci 1982;378:123-36. View abstract.
  33. Lanca S, Alves A, Vieira AI, et al. Chromium-induced toxic hepatitis. Eur J Intern Med 2002;13:518-20. View abstract.
Last reviewed - 02/12/2020