Nettle is a perennial plant found in damp woods and grassy areas in temperate regions throughout the world. It has a creeping root which produces a bristled stem growing from 1 to 2 meters in height. The plant has deep green, serrated, heart-shaped leaves, which are covered on the undersides with fine hairs that cause a burning sensation upon contact with the skin. Nettle flowers in mid to late summer, bearing pale green, incomplete flowers, with male and female often growing on separate plants. The root and leaves are used for health purposes.
Analyses of nettle leaves have revealed over 20 chemical constituents; however, the compound responsible for the pain from contact with nettle has not been determined. Rich in chlorophyll, vitamin C, and beta-carotene, nettle leaves also contain calcium and potassium salts and silicic acid. The root contains beta sitosterol in free forms and as glycosides, as well as a compound known as scopoletin.
The daily dosages approved by Commission E are 8 to 12 grams of fresh or dried nettle leaves and 4 to 6 grams of the root. Nettle has very low toxicity and appears to be safe at these doses. While there are no known side effects associated with the use of nettle leaves, mild gastrointestinal upset has occasionally been reported with the use of the root.