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Stinging nettle

Stinging nettle
© Sertürner Bildarchiv

Botanical name

Greater stinging nettle - Urtica dioica L.
Lesser stinging nettle - Urtica urens L.

Family

Stinging nettle family (Urticaceae)

Common name

Useful information about the plant

The stinging nettle is a cosmopolitan ruderal plant, because it can be found in all temperate zones of Europe, Asia and America, and settles in typical ruderal locations. As such, it grows in human-influenced locations such as waste, rubbish and farmyards, path and roadsides and hedgerows, walls, fences, fields and pastures. These are mostly nutrient-rich soils. The stinging nettle is well known to all people due to their painful burning sensation when you touch the plant. This is caused by stinging hairs on the leaves and stems. Even the slightest touch breaks off their little tips, the broken tip then forms a sharp edge, which pierces the stinging hair into the skin. When under high pressure, the cell sap containing formic acid, acetylcholine and histamine is injected as with a needle under the skin where it causes an itchy rash. This characteristic is reflected in the Latin and German names of the plant. Urtica comes from the Latin "urere" (= to burn), further boosted by "urens" of the Lesser Nettle (U. urens). In English, this "burning" sensation is combined with "nettle" to give its name: stinging nettle. This refers to the use of nettles as a domestic "spun plant" (fibre plant), because before the introduction of cotton in Europe, the sclerenchyma fibres of the nettle stalks were spun into cloth. Nowadays, unbleached cotton is produced from cotton yarn.
Both types of stinging nettle are used medicinally. The perennial stinging nettle (U. dioica) can grow up to 150cm high, the angular stems are covered with stinging hairs and bristles. The serrated leaves are covered in decussate stinging hairs and bristles, they are heart-shaped at the base and taper off sharply. The small inconspicuous flowers are arranged in panicle inflorescences (thyrsi), the plant is unisexual (dioecious - dioica), i.e. that are both male and female flowers are on separate plants. The annual Lesser Nettle (U. urens) is 10 to 50cm significantly smaller, and its rounded leaves are small and only bear stinging hairs, no bristles. The flowers are yellowish and more delicate than those of the Greater Nettle, also, the plant is monoecious. They flower from May to October in both species.

Medicinally used plant parts (drug)

The dried herb (leaves and stems) of both types are used or just the dried leaves and roots. The commercial drug comes from wild resources in Central and Eastern Europe.

Ingredients of the drug

Stinging nettle leaves (also nettle herb) contain flavonoids and caffeic acid esters. Stinging nettle root contains lectins, phytosterols, lignans and polysaccharides.

Descriptions of the quality

The quality of the stinging nettle leaves (folium urticae) is specified in the European Pharmacopoeia (Ph. Eur).
The quality of the stinging nettle root (urticae radix) is specified in the German Pharmacopoeia (DAB).
The quality of the following drugs or drug preparations is specified in the German Drug Codex (DAC):

  • Stinging nettle herb (herba urticae)
  • Stinging nettle tincture (Urticae folii tinctura)
  • Stinging nettle tincture (Urticae radicis tinctura)

Medical Application

Recognised medical use

Stinging nettle leaves
For flushing in inflammatory diseases of the urinary tract and to support the treatment of rheumatic complaints (Commission E, ESCOP); as flushing for the prevention and treatment of renal gravel (Commission E). The HMPC has classified stinging nettle leaves or stinging nettle herb as a traditional herbal medicinal product

Stinging nettle root
Urination problems in prostatic adenoma stage I to II of benign prostatic hyperplasia (Commission E, ESCOP); ESCOP defines the symptoms more accurately: with night-time urge to urinate, upset in the emptying of the bladder with postvoid residual urine, with painful and difficulties in urinating as well as urinary retention.

Traditional use

Stinging nettle leaves and stinging nettle herb
Stinging nettle leaves and the stinging nettle herb were classified by the HMPC as traditional herbal medicines (§ 39a AMG). Based on many years of experience stinging nettle leaves and the stinging nettle herb can be used for mild aching joints and urinary problems as well as with slight problems in the urinary system by increasing the amount of urine and thus lead to a better flushing of the urinary tract. Nettle herb is also used to treat scaly skin.
Traditionally used to support the excretory function of the kidney (traditional use acc. to § 109a).

Stinging nettle root
Traditionally used to help the excretory function of the kidney (traditional use acc. to § 109a).

Medicinal herbal preparations in finished drug products

Stinging nettle leaves vs stinging nettle herb

Stinging nettle root
  • dried extract in tablets and capsules as well as dissolved in liquids

Dosage

Prepared drugs: see packaging leaflet.
Tea infusion: drink a cup of nettle tea (stinging nettle herb tea) 3 to 4 times a day, average daily dose 10 to 20 grams of the drug. There are useful combinations with others drugs, such as True Goldenrod, Restharrow, Orthosiphon leaves or Birch leaves (Bladder and Kidney tea, Urinary tea).
To ensure the effect of stinging nettle root for the treatment of benign prostatic hyperplasia (BPH), it is advised to use this form of finished drug as per the advised dosage in the package leaflet.

Preparation of a tea infusion

Pour 150ml of boiling water over 4 teaspoons (about 2.8g) of finely chopped stinging nettle leaves (nettle herb) and strain after 10 to 15 minutes. The tea infusion with nettle root must be prepared with the coarse powdered drug, 1.5g of drug mixed with 150ml of cold water, bring the mixture to a boil, keep it at the boil for 1 min, then remove from the hob and strain after 10 min.

Advice

Stinging nettle leaves or the stinging nettle herb should not be applied in acute arthritis, on recognisable swelling, redness and fever, because they require medical advice. In the presence of oedema caused by impaired heart and kidney function, a flushing treatment cannot be performed with stinging nettle leaves or herb or stinging nettle root. A combination with draining synthetic drugs (diuretics) is discouraged. Plenty of fluids must be taken during a flushing therapy. There are still no studies on the harmlessness of the stinging nettle leaves or herb during pregnancy and breast-feeding as well as for use in children under the age of 12.

Side effects

The ingestion of stinging nettle leaves (herb) and root may cause skin reactions and occasionally gastrointestinal complaints. For patients with diabetes taking stinging nettle leaves (herb), there have been isolated reports of an increase in blood sugar.

Interactions

None known.

References

Drug monographs

HMPC, Commission E, ESCOP, WHO Vol. 2

Further reading

Wichtl: Teedrogen und Phytopharmaka, pg. 679, 685
Schilcher: Leitfaden Phytotherapie, pg. 66, 67
Van Wyk: Handbuch der Arzneipflanzen, pg. 332
Kommentar zum Europäischen Arzneibuch (stinging nettle leaves, no. 1897)
Kommentar zum Deutschen Arzneibuch (stinging nettle root)

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