Nettles, (Urtica dioica) from the family Urticaceae is also referred to as Stinging Nettle, Common Nettle and Greater Nettle. Nettle plants grow 2 to three feet tall, bearing dark green leaves with serrated margins and small flowers covered with tiny hairs on the leaves and stems. When brushed, Nettles can inject an irritant into any skin that comes into contact with the plant.
This stinging reaction is caused by the plant hairs injecting a compound containing formic acid, histamine, serotonin, acetylcholine, 5-hydroxytryptamine and other irritants. This stinging activity is lost when the plant is dried or cooked, and the tender tops of young first-growth nettles are especially delicious and nutritious.
Found all over the world, Nettles have been used as a vegetable and folk remedy for centuries. Collected before flowering, Nettles were thought useful as a treatment for asthma, as an expectorant, antispasmodic, diuretic, astringent, and tonic. Applying an extract of Nettles to the scalp was said to stimulate hair growth, and chronic rheumatism was treated by placing nettle leaves directly on the afflicted area. This usually led to local irritation, which could be relieved by vigorously rubbing the area. No evidence exist for the belief in Nettles ability to treat baldness. Likewise, Nettles have also been historically used to treat cancer, liver disease, constipation, asthma, worms, arthritis, gout, tuberculosis and gonorrhea, with little if any effectiveness.
The diuretic properties of nettles are well recognized, and several pharmaceutical preparations incorporating Nettles are marketed in Europe for this purpose. In addition, an extract of nettle root has become quite popular in recent years for the treatment of urinary retention brought on by benign prostatic hypertrophy (BPH). Some clinical studies attests to its effectiveness, and German health authorities now allow it to be used for this condition.
The German Commission E monograph indicates use of Nettles for secondary (not primary) treatment for rheumatic complaints, and for irrigation (flushing) in cases of inflammation of the urinary tract and in prevention and treatment of kidney gravel, noting that abundant fluid intake must be assured.
Nettles are rich in chlorophyll and young cooked nettle shoots, when cooked, are not only edible but are an excellent source of beta carotene, vitamin C, vitamin E and minerals, especially silica.
Adverse effects from consuming nettle tea can range from upset stomach to burning sensations in the skin, difficulty in urination and bloating.