To Pee, or Not to Pee

Q: In an episode of 'Friends', one character is stung by a jellyfish, and another comes to her rescue by urinating on the affected area. Apparently a chemical in the pee neutralizes the stinging sensation. Is this myth or fact? If a friend is writhing in pain from a jellyfish attack, and the pressure is on to do something, should you whip it out?

A: Nope. Peeing on jellyfish stings provides more entertainment value than medical assistance. There are two issues to deal with in a jellyfish sting, and urine does not address either one of them effectively.

The Cause
Jellyfish are covered in small cells called nematocysts - basically tiny water balloons with poison darts in the middle. Stings are caused when nematocysts burst and drive the stingers into your skin, and there are always a good number of nematocysts left untriggered that cling to the outside of the wound. Your first job is to get them off, before they can make the situation worse. Urine contains a substance, urea, that was used in the past as an antiseptic (among many other things), but what you need is something that will neutralize the stinging cells. Tests show that urine may actually cause the remaining cells to fire, so that's out. Vinegar seems to neutralize the nematocysts from most jellyfish, even the dreaded Box Jellyfish of Australia, which is so painful that it could kill you by shock alone. A notable exception to this cure is the Portuguese Man-O-War, whose stinger cells may actually be triggered by vinegar. Rinse with salt water instead. In no case should a jellyfish wound be rinsed with fresh water, and nothing should ever be rubbed into the wound. Some experts recommend shaving the affected area with a razor to remove the stingers after the nematocysts have been rendered safe.

The Pain
Jellyfish stings are similar to bee stings, so they respond to similar treatments, such as Benadryl and hydrocortisone. Again, urine doesn't help with the pain of a jellyfish sting, except in one potential fashion. If the person peed on believes it will help, then they may feel an actual lessening of their pain through the "placebo effect", as their mind is calmed by the belief that they have been treated. Yes, this actually works, since a major component of healing is psychological. And it's a lot more interesting for onlookers.