from the Encyclopedia of Herbs and Herbalism:
Urtica dioica L URTICACEAE
Stinging Nettle Nettle/Common Nettle
The Nettle is now a common and painful stinging weed which appears wherever land is disturbed by man and left derelict. In the past, however, it has variously been used in cloth manufacture, as a food, and medicinally. It was once even cultivated in Scotland, Denmark and Norway.
The use of the plant in cloth manufacture only stopped in the first quarter of the twentieth century but can be traced back to the Bronze Age - and is recorded in the common name, nettle, from an old word meaning to twist (and hence make fibre).
Greeks knew it as akalyphe and Romans as urtica - but the ancients probably used the annual U. pilulifera L (or Roman Nettle) rather more, since it is native to southern Europe. Both this species and the Small Nettle (U. urens), which is also an annual, have the same values as U. dioica.
Description Dioccious perennial, from 80-180, cm tall, sterns bristly, sparsely branched, bearing opposite and decussate, acuminate, deeply serrate, petiolate and ovate leaves to 14 cm long. Flowers minute, in pendulous axillary racemes, appearing mid-summer to mid-autumn.
Distribution Widespread; Eurasian native. On wasteland, especially damp and nutrient-rich soils which have previously been disturbed by man; to 2700 m altitude.
Cultivation Wild plant. Cultivated only rarely for medicinal purposes, and as a source of commercial chlorophyll.
Propagated from seed, or by root division in spring.
Constituents (leaves) Histamine; acetylcholine; formic acid. gallic acid; tannins. 5-hydroxytryptamine; vitamins A and C; mineral salts including calcium, potassium, silicon, iron, manganese and sulphur; other active substances; unknown components.
Uses (fresh or dried leaves, root-stock rarely) Astringent; anti-haemorrhagic; diuretic; galactagogue.
The Nettle has many therapeutic applications, but is principally of benefit in all kinds of internal haemorrhages. as a diuretic; in urticaria, jaundice, haemorrhoids; a laxative; and it is used in dermatological problems including eczema.
The powdered leaf used as a snuff stops nose bleeds.
It has been shown to lower the blood-sugar level and also to lower the blood pressure slightly.
Used to promote hair growth rarely, and fresh branches applied externally in rheumatism.
Young shoots and leaves cooked like Spinach.
A commercial source of chlorophyll.
Used in paper and cloth manufacture.