What is it?
Horsetail is used for “fluid retention” (edema), kidney and bladder stones, urinary tract infections, the inability to control urination (incontinence), and general disturbances of the kidney and bladder.
It is also used for balding; tuberculosis; jaundice; hepatitis; brittle fingernails; joint diseases; gout; osteoarthritis; weak bones (osteoporosis); frostbite; weight loss; heavy menstrual periods; and uncontrolled bleeding (hemorrhage) of the nose, lung, or stomach.
Horsetail is applied directly to the skin to treat wounds and burns.
There have been reports of horsetail products being contaminated with a related plant called Equisetum palustre. This plant contains chemicals that can poison cattle, but toxicity in people has not been proven.
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...
- Osteoporosis. Early research suggests that taking dry horsetail extract or a specific product containing horsetail extract plus calcium (Osteosil Calcium) by mouth can increase bone density in postmenopausal women with osteoporosis.
- Kidney and bladder stones.
- Weight loss.
- Hair loss.
- Heavy periods.
- Fluid retention.
- Urinary tract infections.
- Use on the skin for wound healing.
- Other conditions.
How does it work?
Are there safety concerns?
Special precautions & warnings:Pregnancy and breast-feeding: There is not enough reliable information about the safety of taking horsetail if you are 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.
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): 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): There is a concern that horsetail could make thiamine deficiency worse.
Are there interactions with medications?
- 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.
- Water pills (Diuretic drugs)
- Large amounts of horsetail might decrease potassium levels in the body. "Water pills" can also decrease potassium in the body. 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?
- Horsetail and areca 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.
- Crude horsetail contains thiaminase, a chemical that breaks down thiamine. Cattle that eat a lot of horsetail have developed thiamine deficiency.
Are there interactions with foods?
- There are no known interactions with foods.
What dose is used?
To learn more about how this article was written, please see the Natural Medicines Comprehensive Database methodology.
- Henderson JA, Evans EV, and McIntosh RA. The antithiamine action of Equisetum. J Amer Vet Med Assoc 1952;120:375-378.
- 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.
- Maeda, H., Miyamoto, K., and Sano, T. Occurrence of dermatitis in rats fed a cholesterol diet containing field horsetail (Equisetum arvense L.). J Nutr Sci Vitaminol.(Tokyo) 1997;43:553-563. View abstract.
- 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.
- D'Agostino, M., Dini, A., Pizza, C., Senatore, F., and Aquino, R. Sterols from Equisetum arvense. Boll.Soc Ital.Biol Sper. 12-30-1984;60:2241-2245. View abstract.
- Nitta, A., Yoshida, S., and Tagaeto, T. A comparative study of crude drugs in Southeast Asia. X. Crude drugs derived from Equisetum species. Chem Pharm Bull (Tokyo) 1977;25:1135-1139. View abstract.
- Stajner, D., Popovic, B. M., Canadanovic-Brunet, J., and Boza, P. Free radical scavenging activity of three Equisetum species from Fruska gora mountain. Fitoterapia 2006;77(7-8):601-604. View abstract.
- 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.
- 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.
- 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.
- 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.
- Perez Gutierrez RM, Laguna GY, Walkowski A. Diuretic activity of Mexican equisetum. J Ethnopharmacol 1985;14:269-72. View abstract.
- Fabre B, Geay B, Beaufils P. Thiaminase activity in equisetum arvense and its extracts. Plant Med Phytother 1993;26:190-7.
- Henderson JA, Evans EV, McIntosh RA. The antithiamine action of Equisetum. J Am Vet Med Assoc 1952;120:375-8. View abstract.
- 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.
- Husson GP, Vilagines R, Delaveau P. [Antiviral properties of various extracts of natural origin]. Ann Pharm Fr 1986; 44:41-8. View abstract.
- 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.
- 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.
- Langhammer L, Blaszkiewitz K, Kotzorek I. Evidence of toxic adulteration of equisetum. Dtsch Apoth Ztg 1972;112:1751-94.
- 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.
- 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.
- 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.
- Sudan BJ. Seborrhoeic dermatitis induced by nicotine of horsetails (Equisetum arvense L.). Contact Dermatitis 1985;13:201-2. View abstract.
- 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.
- 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).
- 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.
- Lanca S, Alves A, Vieira AI, et al. Chromium-induced toxic hepatitis. Eur J Intern Med 2002;13:518-20. View abstract.