Urtica dioica,  known as common nettle, or stinging nettle is  a herbaceous perennial flowering plant in the family Urticaceae.  The plant is originally native to Europe, Asia and western North Africa but is now, it is now found worldwide. The species is divided into six subspecies, five of which have many hollow stinging hairs called trichomes on the leaves and stems, which act like hypodermic needles, injecting histamine and other chemicals that produce a stinging sensation upon contact (“contact urticaria”, a form of contact dermatitis).

A very common plant, the stinging nettle can be found growing in gardens, hedgerows, fields, woodlands and many other habitats. Its preference for damp, fertile and disturbed ground makes it a good coloniser of places enriched by human activities, such as agriculture and development. Stinging nettles are great wildlife attractors: caterpillars of the small tortoiseshell and peacock butterflies use them as foodplants; ladybirds feast on the aphids that shelter among them; and seed-eating birds enjoy their autumn spoils.

The common nettle is approximately (0.9 to 2 metres) tall in the summer and then dies back in the winter. The leaves and stems are  hairy with non-stinging hairs, and in most subspecies, also bear many stinging hairs (trichomes or spicules), whose tips come off when touched, transforming the hair into a needle that can inject several chemicals causing a painful as suggested by its common name, the stinging nettle.  The plant has a long history of use as a source for traditional medicine, food, tea, and textile raw material in ancient (such as Saxon) and modern societies.