Nettle (Urtica dioica)
The spring has sprung and one of the first plant friends that pops up around this time is Nettle.
Urtication, or flogging with nettles, is the process of deliberately applying stinging nettles to the skin in order to provoke inflammation. An agent thus used is known as a rubefacient (something that causes redness). This is done as a folk remedy for rheumatism, providing temporary relief from pain. The counter-irritant action to which this is often attributed can be preserved by the preparation of an alcoholic tincture which can be applied as part of a topical preparation, but not as an infusion, which drastically reduces the irritant action.
Extracts can be used to treat arthritis, allergies, anemia, hay fever, kidney problems, and pain.
Nettle leaf is a herb that has a long tradition of use as an adjuvant remedy in the treatment of arthritis in Germany. Nettle leaf extract contains active compounds that reduce TNF-α and other inflammatory cytokines. It has been demonstrated that nettle leaf lowers TNF-α levels by potently inhibiting the genetic transcription factor that activates TNF-α and IL-1B in the synovial tissue that lines the joint.
The leaf that has anti-inflammatory properties and seems to reduce prostaglandin production in the body. A study just published in the journal Phytotherapy Research in 2009 demonstrated in the laboratory that the Nettle leaf blocks histamine receptors, and acts to block prostaglandin production by the COX-1 and COX-2 pathways. It also blocks the release of enzymes from mast cells. All those effects together make this a pretty potent anti-allergy medicine. And confirming the lab data are some studies showing that it reduces sneezing and runny nose for people with allergies.
Nettle is used in hair shampoos to control dandruff and is said to make hair more glossy, which is why some farmers include a handful of nettles with cattle feed. It is also thought nettles can ease eczema.
Nettle root extracts have been extensively studied in human clinical trials as a treatment for symptoms of benign prostatic hyperplasia (BPH). These extracts have been shown to help relieve symptoms compared to placebo both by themselves  and when combined with other herbal medicines..
Because it contains 3,4-divanillyltetrahydrofuran, certain extracts of the nettle are used by bodybuilders in an effort to increase free testosterone by occupying sex-hormone binding globulin
Fresh nettle is used in folk remedies to stop bleeding because of its high Vitamin K content. Meanwhile, in dry U. dioica, the Vitamin K is practically non-existent and so is used as a blood thinner.