Precautions on contact

Some species of jellyfish can sting, injecting poison and causing local reactions and, in the case of the Portuguese Man o’ War, occasional systemic effects. These species have cells called cnidocytes used for food and defense, which are like tiny syringes that inject toxic substances through contact with other animals. The cnidocytes are found essentially in the tentacles. In the case of humans, the level of toxicity depends on the species and the amount of poison injected. Cnidocytes remain active even when the animals are dead on the beach sand. Most contacts are accidental and occur on the beach. Therefore, it is important to avoid touching these organisms, especially tentacles.

What to do if stung

Wash the affected area with sea water, without rubbing

Remove any remaining tentacles that may have been left on the skin with a plastic card (it can be a credit card, driver’s license, bus pass, etc.)

What not to do if stung

Do not use fresh water, vinegar*, alcohol or ammonia!

Do not apply bandages!

* with the exception of contact with a Portuguese Man o’ War


If stung by a Portuguese Man o’ War

After washing and cleaning the affected area with sea water:

  • Apply hot packs (40º C) for about 20 minutes or,
  • Apply vinegar without diluting
  • If you are in shock, have difficulty breathing or the pain persists, see your doctor or pharmacist.
foto Maria Pinto

If stung by a Jellyfish

After washing and cleaning the affected area with sea water:

  • Apply ice packs for about 15 minutes
  • If pain persists, consult your doctor or pharmacist
foto Paulo B. Oliveira
foto Paulo Vasconcelos