Rachel was once stung by a jellyfish in the Indian Ocean, and her husband wanted to pee on her leg to help with the sting. Should she have let him? The science does not tell us. A study reviewing what we know about treating jellyfish stings concludes that we do not really know what to do. Experts all over the world disagree. One study does show that if you are stung by a Portuguese man-of-war, putting the sting in very hot water may reduce your pain but putting ice on it does not. Some people recommend using vinegar on jellyfish stings because it has been shown to stop tropical jellyfish stingers from firing in laboratory studies. However, vinegar does nothing to ease the pain from stingers that have already fired and it might even make the firing worse for some types of jellyfish. Other remedies, including urine, have not been studied. There is no reason to think that urine would help. In fact, if the urine dilutes the salt water around the stingers, it may cause them to fire more. With no evidence that urine helps and the possibility that it may hurt, our motto in this situation would be: ‘When in doubt, don’t let someone pee on you.’