Horsetail (Equisetum arvense) is an herbal remedy that dates back to ancient Roman and Greek times. It was used traditionally to stop bleeding, heal ulcers and wounds, and treat tuberculosis and kidney problems. The name Equisetum is derived from the Latin roots equus, meaning “horse,” and seta, meaning “bristle.”
Horsetail contains silicon, which helps strengthen bone. For that reason, some practitioners recommend horsetail as a treatment for osteoporosis. It is also used as a diuretic, and as an ingredient in some cosmetics. However, few studies have investigated horsetail’s effect in humans.
Horsetail has traditionally been used as a diuretic (helps rid the body of excess fluid by increasing urine output). One study examined the use of horsetail by people who had a history of uric acid kidney stones. The people who took horsetail experienced an increase in diuresis (urine output). Other studies suggest horsetail has antioxidant properties and may inhibit cancer cell growth.
Horsetail has been suggested as a treatment for osteoporosis (thinning bone), because it contains silicon, a mineral needed for bone health. In one study, 122 Italian women took horsetail dry extract or Osteosil calcium 270 mg twice daily (a horsetail/calcium combination used in Italy for osteoporosis and fractures). Both groups who took horsetail experienced improved bone density, however the study was poorly designed. More research is needed to determine whether horsetail has any effect on bone density.
Horsetail is sometimes suggested for the following conditions:
- Kidney stones
- Urinary tract infections
- Brittle nails
- Minor wounds and burns (applied topically; not suggested for open wounds).
Some known precautions
People with heart or kidney disorders, diabetes, or gout should not use horsetail.
Horsetail may flush potassium out of the body so people who are at risk for low potassium levels should not take Horsetail. (Sweet potatoes, regular potatoes, watermelon, and spinach are great sources of potassium.)
Women who are pregnant or breastfeeding should not take horsetail.