It’s an old staple of summer trips to the beach but the British Red Cross has challenged the idea that urine can be used to treat jellyfish stings.
The charity instead suggests people treat such stings with salt water or vinegar.
It has issued the advice following warnings from the Marine Conservation Society that there are increasing numbers of jellyfish along Britain's coastline.
The recent hot weather means bathers have a higher risk of running into the creatures with increased sightings of moon, compass, blue and lion's mane jellyfish.
Joe Mulligan, British Red Cross head of first aid, said: "A sting from a jellyfish can be extremely painful, but trying to treat it with urine isn't going to make your day any better. Urine just doesn't have the right chemical make-up to solve the problem.
"If people have been stung, they need to get out of the water to avoid getting stung again. Once out, slowly pouring seawater over the sting will help ease the pain.
"Doing the same thing with vinegar can be even more effective as the acid helps neutralise the jellyfish sting. But, unless you're near a chip shop, seawater will probably be easier to find."