Horsetail (Equisetum arvense), an herbal remedy since ancient times, has traditionally been used to stop bleeding, increase urine production, repair broken bones, and treat rheumatic conditions such as arthritis. Today, horsetail continues to have medicinal value. The plant's stems are rich in silica and silicic acids, which help mend broken bones and form collagen, an important protein found in connective tissue, skin, bone, cartilage, and ligaments. Horsetail is also used as a diuretic, a treatment for kidney and bladder complaints, and an external therapy for bleeding wounds.

Horsetail is a descendent of huge, tree-like plants that thrived 400 million years ago during the Paleozoic era. Closely related to ferns, horsetail is a non-flowering weed found throughout parts of Europe, Asia, the Middle East, and North America. The plant is a perennial (returns each year) with hollow stems and shoots that look like asparagus. As the plant dries, silica crystals that form in the stems and branches give the plant a scratching effect, thus accounting for its historic use in polishing metal, particularly pewter.

The aboveground parts of horsetail (fresh or dried) are used for medicinal purposes.

Taken internally, horsetail is used to treat the following conditions and symptoms:

• Inflammation or mild infections of the genitourinary tract 
• Kidney stones 
• Bladder stones 
• Bedwetting 

Horsetail also can be applied externally to treat the following:

• Wounds (especially poorly healing ones) 
• Burns 
• Rheumatic conditions 
• Fractures 
• Sprains 

Horsetail is available in the following forms:

• Dried herb 
• Liquid preparations 

Horsetail preparations should be stored in well-sealed containers to ensure protection from light.

Adequate fluid should be consumed when taking horsetail preparations orally. A tea is prepared by pouring boiled water over 2 to 3 g horsetail herb, boiling for five minutes, and then straining after 10 to 15 minutes. Drink during the day between meals. An infusion for internal use is made by adding 1.5 g of horsetail herb to 1 cup of boiling water. Let it steep for 30 to 40 minutes.

Pediatric

• For fractures and bedwetting, adjust the recommended adult dose to account for the child's weight. Most herbal dosages for adults are calculated on the basis of a 150 lb (70 kg) adult. Therefore, if the child weighs 50 lb (20 to 25 kg), the appropriate dose of horsetail for this child would be 1/3 of the adult dosage.

Adult

• Internal: 6 g per day 
• Herbal infusion: 4 oz three times per day 
• Tincture (1:5): 1 to 4 mL three times per day 
• External (compresses): 10 g of herb per 1 L water per day 

Horsetail remedies prepared from Equisetum arvense are generally considered safe. However, you should not take horsetail if you have edema (excessive fluid in body tissue) associated with heart or kidney problems. If you are planning to use fresh horsetail in a bath, you should first consult your health care practitioner. Also, other species of horsetail such as Equisetum palustre are poisonous and should not be used.

Although there have been reports that horsetail acts as a diuretic, no noteworthy interactions (positive or negative) between horsetail and conventional medications are known to have been reported in the literature to date.

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