Every kid at some point got stung by a nettle at least once. It was many times in my childhood, but without fail whenever it happened someone, be it an adult or friend, would tell me to quickly find a dock leaf, and rub it on the sting. I would always comply without question, as I’m sure any child would do, and quickly go off looking for a dock leaf to vigorously rub on the sting. I think it did kind of help…maybe, but the sting never went away properly, and would itch later. I always put this down to not getting the dock leaf fast enough, or the fact that the dock leaf disintegrated whilst rubbing, so I didn’t get a full dosage of the antidote, but now I’m not so sure. So here I’ve looked at the science of dock leaves and nettles, to see if dock leaves help nettle stings, as they are claimed to.
The leaves of stinging nettles contain lots of little hairs, which act as a toxin delivery system to anyone who brushes up against them too vigorously. Different nettles from different parts of the world seem to contain different chemicals which cause the sting. For example, Urtica thunbergiana a species of nettle native to Japan contains oxalic acid and tartaric acid, whereas the needles in Urtica dioica, the species which is native to Europe and North America, contains formic acid, histamine, serotonin and acetylcholine. Seeing as I am from Europe, and not writing in Japanese, I’ll look into the European nettles and their chemicals.
Formic acid – Obviously an acid, and one which can pack a punch. This acid is found throughout nature and stinging ants use formic acid in their venom too. Like all acids, it hurts to have it on your skin. You would expect dock leaves to contain something that can neutralise this acid if they can combat a nettle sting.
Histamine – This is a chemical which we naturally produce and use to regulate the inflammatory response of our immune system – the more histamine in an area, the more inflamed it will become. It is because of histamine that nettle stings go red and itchy (although I’m sure the formic acid also triggers an inflammatory response too). Histamine is found throughout nature, and its high content in strawberries is the reason babies cannot eat them! You would expect dock leaves to hopefully contain an antihistamine which will counteract histamine. Histamine itself doesn’t seem to cause pain, but it can cause that persistant itchy sensation that nettle stings can give you.
Serotonin – Serotonin is a neurotransmitter which we naturally produce, and although commonly associated with mood, serotonin does act as an irritant when injected.
Acetylcholine – This is another chemical we commonly produce in our own body, and the most interesting to be found in a nettle sting. Acetylcholine is a very important neurotransmitter, with a number of roles in the body. Oddly, acetylcholine seems to possess pain relieving properties rather than irritating properties. When injected into rats (to try and identify what caused pain from a nettle sting), acetylcholine didn’t cause any harm. As there is nothing to suggest that acetylcholine actually causes pain, I won’t look into how dock leaves can inhibit it.
So, the main culprits in a nettle sting are formic acid, histamine and serotonin.
Dock leaves pose little interest to botanists and attract very little research from anyone. The reason for attracting little attention is that they are pretty average for a plant and don’t contain any interesting phytonutrients. So, although there isn’t anything specific about dock leaves, we can make assumptions on what is in a dock leaf based on typical plant compositions.
For starters, plant sap has a pH of 6.4, which is very close to a neutral pH, and actually very slightly acidic. Although it isn’t as acidic as formic acid, a pH of 6.4 is unlikely to be able to neutralise the formic acid from the nettle sting significantly.
Next we will look at histamine, to counter the effects of histamine, a dock leaf should contain an antihistamine chemical, or at least an anti-inflammatory. Anti-inflammatories are found in some specialised plants, the most famous being turmeric, which is the only source of the anti-inflammatory curcumin. Dock leaves are very unlikely to be contain any anti-inflammatories though. The only plants which contain anti-inflammatories are herbs, and dock leaves are not related to herbs. So dock leaves probably can’t stop the inflammation and itching caused by stinging nettles.
Dock leaves are also unlikely to be able to inhibit the action of serotonin either. Plants containing anything that can inhibit serotonin are even rarer than ones which contain anti-inflammatories, and again, they are usually herbs.
Finally, we have already ascertained that the acetylcholine found nettle sting probably doesn’t cause pain. Even if it did, dock leaves won’t contain anything that can inhibit its action.
The act of rubbing nettle stings can actually stimulate certain nerves, which can reduce pain. This has nothing to do with the dock leaf, but the act of rubbing the dock leaf (or any leaf) can help reduce the pain from stings.
There is nothing in a dock leaf which can neutralise or counteract the pain and inflammation from a nettle sting. As plants go, dock leaves are unimpressive. However, the act of rubbing a dock leaf on a nettle sting can help reduce the pain. It is the rubbing which reduces the pain though, not the dock leaf.
So next time you, or someone you are with gets stung by a nettle, just rub the sting with your finger, it has the same effect as a dock leaf, except your finger won’t disintegrate and turn the sting green with sap.
This Youtube video will give an overview of the information found on the article tab. If you want to know more about the topic, or want to see where the information came from, have a read of the article after you watch the video.
Yes. Although there is nothing in a dock leaf which can neutralise the nettle sting, the act of rubbing a sting can reduce the pain. There is no need for the dock leaf though.