Nettle is a genus of flowering plants comprised of roughly 40 different species. Most species are perennial, and many share a well-known attribute — stinging hairs. This is where various species of the genus Urtica get the name "stinging nettle." Perhaps the most common species is Urtica dioica, which is a stinging nettle found in Europe, Asia, and North America.
The sting is caused by coming in contact with the tiny stinging hairs, which are most concentrated on the stems of the plants. These hairs contain a cocktail of histamine, serotonin, and formic acid. Nettles are also suspected to contain oxalic acid and tartaric acid. While the exact makeup of these toxins is under investigation, the effect is certain. Contact with the stinging hairs of the plant causes painful stinging and allergic reactions in the skin, including welts, hives, itching, burning sensation, and general irritation. One species, Urtica ferox, which is found in New Zealand, has even been known to cause death in animals and at least one human.
Although nettle may seem a menacing plant, it has been used for centuries in various trades. The use dates back as far as ancient Greece, and throughout history, they have been used the world over for a variety of purposes. If the stinging hairs of the plant are removed through steaming or boiling, nettle can be eaten or made into a tea. The plant is high in nutrients, including iron and calcium. The stems are a commonly used raw material in paper-making, and the fibers of the plant can be used to make textiles.
Various species are used for medicinal purposes. However, stinging nettle is the species most prominently used in herbal medicine and other trades. In herbal medicine, it can be used in the form of creams, teas, fluid extracts of the roots and leaves, and dried leaves. Nettle has been utilized for centuries as an herbal remedy to treat eczema, gout, arthritis, rheumatism and anemia. Other medicinal uses include herbal treatments for urinary problems such as kidney stones and urinary tract infections, as well as to counteract prostate enlargement.
This plant can also be useful in treating hay fever, joint pain, sprains, and tendinitis. Perhaps counterintuitively, nettle can also be used as a treatment for pain and irritation. When the stinging hairs come in contact with an area of the body, or a patch of skin that is already irritated or in pain, the compounds in the nettle can have a counterirritant effect, easing the original irritation or pain.