Nettle
Botanical name
Urtica dioica L.
Urtica urens L.
Family
Urticaceae
Common name
Stinging nettle, Common nettle (U.dioica)
Annual nettle, Burning nettle, Small nettle, Dwarf nettle (U.urens)
Information about the plant
Nettle is a cosmopolitan ruderal plant, as it is found in all temperate zones of Europe, Asia, and America, where it typically grows in ruderal habitats. This term is used to describe human-influenced sites such as rubble, landfills, farmyards, roadsides, hedges, walls, fences, fields, and pastures - usually nutrient-rich grounds.
The nettle is well known to everyone for its painful burning sensation when touched. This is caused by the stinging (urticating) hairs on the leaves and stems. Even a light touch causes the small tip to break off, forming a sharp edge with which the stinging hair pierces the skin. The highly pressurized cell sap, containing formic acid, acetylcholine, and histamine, is injected under the skin like a needle, causing an itchy rash. This property is reflected in the Latin and German names of the plant. Urtica is derived from the Latin 'urere' (= to burn), reinforced by the species epithet urens in the case of the small stinging nettle (U.urens). In German, this "Brennen" is combined with "Nessel", referring to the use of nettle as a native "spun plant" (fiber plant), because before the introduction of cotton in Europe, the sclerenchyma fibers of the nettle stalks were spun into cloth. Nowadays, nettle cloth is made from unbleached cotton yarns.
Both nettle species are used medicinally. The perennial stinging nettle (U.dioica) can grow up to 150 cm high, with a square stem covered with stinging (urticating) and bristle hairs. The serrated leaves with bristly and stinging hairs are cross-opposite; they are cordate at the base and taper towards the tip. The small, inconspicuous flowers are arranged in panicle-like inflorescences (thyrses); the plant is dioecious (dioica), i.e. male and female flowers are on different plants.
The annual small nettle (U.urens) is considerably smaller at 10 to 50 cm, its rounded leaves are also smaller and only have stinging hairs, not bristle hairs. The flowers are yellowish and more delicate than those of the stinging nettle; the plant is also monoecious. Both species flower from May to October.
Medicinally used parts of plants (herbal drug)
The dried leaves (nettle leaf - Urticae folium) or the dried herb (nettle herb - Urticae herba) consisting of stems and leaves, as well as the roots (nettle root - Urticae radix), are used from both species. The commercially available drug comes from wild sources in Central and Eastern Europe.
Constituents of the herbal drug
Nettle leaves (also nettle herb) contain flavonoids and caffeic acid esters, while nettle root contains lectins, phytosterols, lignans, and polysaccharides.
Quality of the drug
The quality of the following drugs is specified in the European Pharmacopoeia (Ph. Eur.):
- Nettle leaf (Urticae folium)
- Nettle root (Urticae radix)
- Urtica dioica for homeopathic preparations (Urtica dioica ad praeparationes homoeopathicas)
Medical applications
Recognised medical use
Nettle leaf and nettle herb
The HMPC has classified nettle leaf and nettle herb as traditional herbal medicinal products (see "Traditional use").
ESCOP: Nettle leaf/nettle herb: adjuvant in the symptomatic treatment of arthritis, arthroses and/or rheumatic conditions; also to enhance renal elimination of water in inflammatory complaints of the lower urinary tract (bladder).
Nettle root
The HMPC has classified nettle root as a traditional herbal medicinal product (see "Traditional use").
ESCOP: for the symptomatic treatment of micturition disorders in benign prostatic hyperplasia (BPH) at stages I and II (defined by Alken) or stages II and III (defined by Vahlensieck) such as painful and frequent urination, nocturia, and urine retention.
Traditional use
Nettle leaf and nettle herb
Nettle leaf and nettle herb have been classified by the HMPC as traditional herbal medicinal products (Article 16a of Directive 2001/83/EC). Based on long-standing use, nettle leaf and nettle herb can be used to relief of minor articular pain and for urinary tract disorders to increase the amount of urine and thus improve flushing of the urinary tract. Nettle herb can also be used externally to treat seborrheic skin.
Nettle root
Nettle root has been classified by the HMPC as a traditional herbal medicinal product (§ 39a AMG). Based on long-standing use, nettle root can be used for urinary tract symptoms related to benign prostatic hyperplasia (BPH) after serious conditions have been excluded by a medical doctor .
Herbal drug preparations in finished dosage forms
Nettle leaf or nettle herb
- Cut nettle leaf or cut nettle herb as tea
- Powdered herb in coated tablets
- Dry extracts in tablets and capsules
- Fresh pressed plant as juice
- Urtica dioica homeopathic mother tincture in drops
- Dry extracts in tablets and capsules as well as dissolved in liquids
Dosage
Finished medicinal products: see patient information leaflet.
Tea infusion: drink a cup of nettle leaf tea (nettle herb tea) 3 to 4 times a day; the average daily dose is 10 to 20 g of the drug. In the case of urinary tract infections, a combination with other drugs such as goldenrod, spiny restharrow root, cat’s whiskers leaves or birch leaves is useful (bladder and kidney tea, urine tea); to ensure the effect of nettle root in the treatment of benign prostatic hyperplasia (BPH), it is recommended to use it in the form of finished medicinal products; the dosage can be found in the patient information leaflet.
Preparation of a tea
Pour approx. 150 mL of boiling water to 4 teaspoons (approx. 2.8 g) of finely cut nettle leaves (nettle herb) and strain after 10 to 15 minutes. The tea infusion with nettle root must be prepared with the raw powdered drug; for this, 1.5 g of drug per dose is mixed with 150 mL of cold water, the mixture is brought to a boil, kept boiling for 1 minute, then removed from the heat and strained after 10 minutes.
Notes
Nettle leaf or nettle herb should not be used when articular pain is accompanied by swelling of joint, redness or fever, in which case a doctor should be consulted. In the presence of edema due to impaired heart and kidney function, flushing therapy with nettle leaf or nettle herb, or nettle root should not be carried out. A combination with synthetic dehydrating drugs (diuretics) is not recommended, and plenty of fluids must be drunk during flushing therapy. If minor urinary tract complaints worsen and symptoms such as fever, dysuria, spasm, or blood in the urine occur during the use of this medicinal product, a doctor or a qualified health care professional should be consulted.
Safety during pregnancy and lactation has not been established.
Due to a lack of evidence, the use in children under 12 years of age is not recommended.
There is no indication of the use of nettle roots by women, children, and adolescents under 18 years of age.
Side effects
When taking nettle leaf (herb) and nettle root, mild gastrointestinal complaints (e.g. nausea, vomiting, diarrhea) and skin reactions (e.g. itching, exanthem, hives) may occur.
Interactions
None known.
References
Herbal drug monographs
HMPC (2008, 2011, 2012, 2022), ESCOP (2016, 2019), WHO (Vol. 2, NIS)
Further literature
None