"IMMEDIATE FIRST AID ADVICE:
1. Rinse the area liberally with seawater or fresh water to remove any tentacles stuck to the skin. This can be from a spray bottle or in a beach shower. Do not apply vinegar. A study shows that vinegar in these stings sometimes makes the sting worse. (Portuguese man-of-wars belong to a different family than box jellyfish [Carybdea alata] and therefore must be treated separately.)
2. For severe pain, try applying heat or cold, whichever feels better to the victim.
3. Few Portuguese man-of-war stings cause life-threatening reactions, but this is always a possibility. Some people are extremely sensitive to the venom; a few have allergic reactions. Consider even the slightest breathing difficulty, or altered level of consciousness, a medical emergency. Call for help and use automatic epinephrine injector if available."