Poisoning due to a sting from jellyfish.

Poisonous Ingredient 

  • jellyfish venom

Where Found 

  • jellyfish or Portuguese Man-of-War (Physalia species)  
  • jellyfish or sea-wasp (Chironex fleckeri, Chiropsalmus quadrigatus), found near the coasts of Northern Australia and the Philippines.  
  • related species

Note: This list may not be all inclusive.

Portuguese Man-of-War:

  • body as a whole       o numbness and arm or leg pain       o chest pain       o swallowing difficulty       o weakness       o muscle pain       o muscle spasms       o sweating  
  • eyes, ears, nose, and throat       o runny nose       o watery eyes  
  • skin       o red raised areas where stung  
  • gastrointestinal       o abdominal pain       o nausea  
  • heart and blood vessels       o alteration in pulse rate  
  • nervous system       o headache


  • body as a whole       o pain (severe)       o swelling  
  • respiratory       o difficulty breathing  
  • gastrointestinal       o nausea       o vomiting  
  • skin       o starts to die in the area of the sting  
  • heart and blood vessels       o heartbeat slowed

Home Treatment 

Portuguese Man-of-War:
Wash with salt water. Remove any tentacles and stinging units (nematocysts). Protect affected area if possible. Soak the area with a solution of vinegar and water (1/2 vinegar and 1/2 water) for about 30 minutes to remove any remaining tentacles. Rinse the area and then resoak with more 1/2 strength vinegar.

(May also use alcohol in place of vinegar. To remove remaining tentacles, may use flour or shaving cream and scrape with a sharp instrument.) Apply a cream containing a pain killer, an antihistamine, and a corticosteroid.

Sea-Wasp (usually found in Australian waters):
CALL FOR AN AMBULANCE. Death can occur within minutes.

Before Calling Emergency 
Determine the following information:

  • the patient’s age, weight, and condition  
  • the name of the marine animal if possible  
  • the time stung

Poison Control, or a local emergency number 
They will instruct you if it is necessary to take the patient to the hospital, and any appropriate first aid that can be administered prior to arrival.

What to expect at the emergency room 

Some or all of the following procedures may be performed:

  • Portuguese Man-of-War       o Open and maintain airway if necessary.       o Treat the symptoms.  
  • Sea Wasp       o Give antiserum.       o Treat the symptoms.

Expectations (prognosis) 
Portuguese Man-of-War stings are rarely fatal. Sea-Wasp stings can be fatal in minutes.

Johns Hopkins patient information

Last revised: December 6, 2012
by Dave R. Roger, M.D.

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All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.