ODRO
Writing in the Journal of Emergency Medicine, the authors from NHS Fife said the sap from the leaf may be more important than the plant species.
“If so, any large, fresh and non-toxic leaf would do the job, and dock may have become the leaf of choice simply because it grows in similar habitats to nettle,” they wrote.
“It is possible that the same relief would have occurred with no treatment at all, and our study design does not permit us to conclude that either dock or lettuce is better than simply doing nothing.
“We conclude that dock leaf may work for nettle stings, but lettuce may be just as good, and relief comes quickly either way.”
Lettuce was chosen because it is a similar size, shape and texture to dock leaves but has no anti-inflammatory or toxic properties.
Dock leaf remedy cited by Chaucer
Nettles are a common native plant in the British Isles. Their stems and leaves are covered in stinging hairs – known as trichomes – with a brittle tip that snaps off when touched, releasing a mini jet of the chemicals histamine, formic acid acetylcholine and serotonin into the skin.
Being stung can bring a burning and itchy sensation, white or red spots and red raised patches that can take several days to disappear.
Rubbing a dock leaf on a nettle sting was first mentioned 600 years ago by Geoffrey Chaucer in Troilus and Criseyde, but there is little evidence that it contains special properties that would make it more beneficial than other plants.
It has been speculated that dock may contain natural antihistamine that reduces irritation but none have ever been found.
Likewise, it was once thought the alkaline sap might neutralise the formic acid in nettles, but it has since been found that dock sap is also acidic.
The relief brought by dock leaves is generally believed to be derived from the cooling sensation as the sap evaporates coupled with a placebo effect.
