MedicineNet.com - Jellyfish Stings FAQs

Jellyfish stings are an all-too-common health hazard for beach vacationers. While most jelly fish stings are harmless (with a few exceptions), they can be extremely painful. The stinging sensation results when stingers at the ends of the tentacles of jellyfish and other aquatic animals come into contact with human skin, usually while wading or swimming in the ocean.