So you are enjoying a nice swim in the ocean when you feel an instant burning on your leg from an unknown source. Chances are you have just been stung by a jelly (I say jelly because it is the more scientifically correct term and they are not in any way fish). You make it back to the beach and need to ease the pain with nothing but a helpful friend at your disposal (who recently ingested a very large amount of fluid–do you see where I am going with this?). What do you do?
The One With The Jelly
Friends popularized it in 1997 when Joey, Chandler, and Monica found themselves in the same conundrum. With Monica screaming in pain, the guys remember something that they supposedly saw on the Discovery Channel–urine helps neutralize the pain from jelly stings.
This remedies Monica’s problem in the episode, but does this slightly unsightly venom deactivation technique actually work?
More Harm Than Good
The tactic that is featured in the fictional situation was just that, fiction. In fact, urinating on a jelly sting will likely cause more harm than good.
On the surface of a jelly’s tentacles are stinging cells called cnidocytes. Within these cells are organelles (like the mitochondria inside your own cells) called nematocysts. When potential prey (or your leg) comes into contact with these cells, tiny harpoons explode out of the cells, embed themselves in tissue, and start delivering venom, which causes the intense pain. You can actually see these nematocysts firing in this awesome video:
–Embedding is disabled, so I apologize that you have to watch this on YouTube, but it is worth it for the visuals.
After the nematocysts embed their tiny barbs in your tissue, the pain begins. The pain radiates from the sting site and starts to itch, burn and throb as it blisters. Scratching it, though, can make the pain worse, because rubbing activates the nematocysts, which release more venom. Unfortunately for this urea-based myth, urine actually can stimulate the jelly’s stingers to produce more venom, increasing the victim’s pain.
This myth does have a kernel of truth to it. Toxicologists do recommend washing the area with saltwater, and urine can be very salty. Such rinsing will deactivate those pesky nematocysts that are still hanging on. However, most people’s urine does not have a high enough concentration of salts to deactivate the stinging. If the person has enough urine stored up to urinate, their diluted urine will probably upset a gentle balance.
Any change to the balance of solutes, such as the concentration of salts inside and outside of the stinging cells, sets off stinging. Adding freshwater to the sting site dilutes the salts outside the cell, unbalancing the solutes. In reaction to this change, the nematocysts in the cells release more venom–and cause more pain. Therefore, fairly dilute urine, like most of us produce, will probably cause the stinging to increase not decrease.
Most stings in North American waters can be treated by vinegar, or 5 percent acetic acid. For stings from a few species, Cyanea capillata and Chysaora quinquecirrha, a baking soda and seawater paste is even better. However, time, not urine, is the best treatment for a jelly sting.
Concludes dermatologist Joseph Burnett:
[For a jelly sting] Urine is worthless.
[Via Scientific American]