Why do nettles sting? And do dock leaves really help?

Stinging nettles are the bane of summers day walks.

I remember when I was little and going on walks with my Dad and brushing my hands through the plants and then getting stung. My dad immediately reached for a dock leaf and wrapped my hand and rubbed the stinging area with it. I was then up and off on my way but why do nettles sting and did the dock leaf really help me?

Types of stinging nettles

Urtica dioica

Urtica dioica (Photo: Derek Harper/ Wikimediacommons)
Urtica dioica (Photo: Wikimediacommons / D. Harper)

This is the most common nettle found in Europe and is most likely the species of stinging nettle that comes to mind first. It has the common names of common nettle or stinging nettle.

It can be identified by its green leaves with deeply serrated edges. It is found often as an understory plant in damp environments but also in meadows, disturbed or enriched ground. The stems and underside of the leaves are covered in hollow hairs which can sting you.

Urtica incisa

This nettle is found only in Australia and New Zealand but is also referred to as stinging nettle or scrub nettle. It has a similar appearance to Urtica dioica with long leaves with serrated edges but often the leaves are more separated than Urtica dioica.

The leaves are covered in stinging hairs which inflict a sting when touched. It grows in rainforests and in disturbed areas.

Hesperocnide tenella

This nettle species is found predominately in California and is more commonly known as western stinging nettle. It has a similar appearance to the other nettle species with leaves that are deeply serrated and it has thin stems.

The leaves are covered in tiny hairs however they are shaped like hooks and contain formic acid which causes the sting.

Why do Nettles sting?

The nettles sting is an adaptation to provide protection from predators. The sting causes any predator that may eat the plant or uproot it to stay clear.

The way the sting works is like a hypodermic needle. When the hairs embed themselves into the skin they break off the plant and then release a concoction of formic acid, histamines and other chemicals which cause the stinging affect.

Do dock leaves help nettle stings?

Dock leaves come from the genus Rumex and there are several species. The most common species that grows in the UK is the broadleaved Dock. It is characterized by its large oval leaves that have rounded tips. Some of the stems and leaves may have a reddish hue. It can be found in a lot of similar places to nettles such as in meadows and in damp understory areas.

There are a few theories to suggest why dock leaves appear to help nettle stings. It has been found that the sap in dock leaves contains an antihistamine this can soothe the stinging sensation.

It has also been suggested that the cooling sensation of the sap evaporating from the skin affected by the sting can relieve some of the sensations.

The third theory is that it is a placebo effect. The belief of dock leaves helping nettle sting is such a wide and popular opinion that it works because people believe it works. In my view if you are inflicted with a nettle sting it is definitely worth a try!

Keep an eye our for nettles on a walk in your local wood