Question: Why do nettles sting and dock leaves help?

Hayley Clissold answered on 24 Jun 2015:

Nettles are covered in little hairs that act kinda like a needle. These needle-like hairs are able to inject several chemicals into our skin (such as acetylcholine and histamine) that give us a stinging sensation. Similarly, dock leaves contain chemicals that, luckily, are able to provide a cooling, neutralising effect on the nettle sting. Since both of these plants favour growth in similar conditions, both nettles and dock leaves are often found nearby.