Horsetail is found throughout the temperate climate zones of the Northern Hemisphere, including Asia, North America, and Europe. Seven of the twenty-five known species are British, the most common being Equisetum arvense. The Horsetails belong to a class of plants called ‘Equisetaceae’, and are similar to the fern family, germinating in the same way. The class includes only a single genus, Equisetum, the name derived from the Latin words ‘equus’ (a horse) and ‘seta’ (a bristle), from the peculiar bristly appearance of the jointed stems of the plants, and ‘equisetum arvense’ translates to ‘horse tail of the fields’.
The folk names, Scouring Rush and Shave Grass, are thought to allude to this plant’s use as a very fine type of sandpaper, as it was used to file, polish and scour various surfaces such as wood and stone.
The epidermis contains so much silica that bunches of the stem have been sold for polishing metal and used to be imported from Holland for the purpose, hence the popular name of ‘dutch rushes’. It was used many years ago for scouring pewter and wooden kitchen utensils, and thence called ‘pewterwort’, and fletchers and comb makers rubbed and polished their products with it. Dairymaids of the northern counties of England also used it for scouring their milk-pails.
Horsetail is a unique plant that can grow up to 40 feet tall. It reproduces by spores, and has two distinctive types of stems. One variety of stem grows early in spring and looks similar to asparagus, is brown in colour, and has spore-containing cones at the top. The mature form of the herb, appearing in summer, has branched stems, which are thin and green, and look feathery. Only the barren stems are used medicinally, which appear after the fruiting stems have died down. They are used whole, and cut off just above the root. The herb is used either fresh or dried, but is said to be most effective when fresh.
Primary chemical constituents of Horsetail include flavonoids (15 different types), bitter principle, alkaloids (equisetin, nicotine, palustrine, palustrinine), silica, calcium, potassium, manganese, magnesium, sulphur, phytosterols, and tannin. Horsetail is rich in silicic acid and silicates, which provide approximately 2-3% elemental silicon.
The presence of the flavonoids and saponins are believed to have a diuretic effect, while the silicon content is thought to assist in strengthening connective tissue and provide anti-arthritic actions. Some experts have suggested the element silicon, present in horsetail, is also a vital component for bone and cartilage formation, making it beneficial in preventing osteoporosis.
Horsetail is believed to have been first recommended by the Roman physician Galen in ancient times, and it has been employed in various different cultures as a herbal remedy for problems such as arthritis, and kidney and bladder problems. Horsetail has been used for many years in both Chinese and European herbal medicine to treat external wounds - because of its high tannin content, Horsetail helps stop wounds bleeding, making it a popular treatment for nosebleeds and haemorrhoids.
In modern medicine, Horsetail is used to help alleviate painful urination, reduce inflammation of the prostate gland and for treating ulcers, particularly in the urinary passages. It is a diuretic and astringent, and has been found beneficial in treating kidney problems. The ashes of the plant are considered very valuable in normalising acidity of the stomach, and for dyspepsia, etc.