Skip to content
My WebMD Sign In, Sign Up

First Aid & Emergencies

Font Size

Jellyfish Sting Treatment

Call 911 if:

  • The person displays signs of a severe allergic reaction.
  • The sting is from a box jellyfish.
  • The sting covers more than half an arm or leg.

For more information about severe allergic reaction, see Anaphylaxis .

1. Get the Person Out of the Water

2. Stop Stinging

For a jellyfish sting in non-tropical waters:

  • Wash the area with seawater to deactivate stinging cells.

For a sting in tropical waters -- especially from box jellyfish:

  • Rinse immediately with vinegar. Do not use fresh or tap water, which can reactivate stinging cells.
  • Continue until you can get medical help.


3. Decontaminate and Remove Tentacles

For jellyfish stings, the American Heart Association and the American Red Cross have recommended the following:

  • Rinse the area with vinegar for at least 30 seconds. If vinegar is not available, a solution of baking soda can be used. This will deactivate the stinging cells.
  • Next, soak the area in hot water for at least 20 minutes if possible. Cold packs can be used instead if the area can’t be soaked in hot water..

These treatments are based on research done in the Indo-Pacific areas, however, and may not be effective in the oceans of the North Atlantic . In fact, in this area, vinegar may actually make the symptoms worse, depending on the type of jellyfish. Some experts therefore recommend a hot water rinse and lidocaine applied to the area if available.  If this is not possible, then removing the stinging cells and rinsing in seawater would also be an option.

4. Treat Discomfort

  • Use mild hydrocortisone cream or oral antihistamine to relieve itching and swelling.

5. Follow Up

For less severe sting:

  • Use ice packs or over-the-counter pain relievers for welts.
  • Clean open sores 3 times a day and apply antibiotic ointment. Bandage if needed.

For a severe reaction:

  • The person may be hospitalized for several days.
  • Anti-venom will be administered for box jellyfish stings.

WebMD Medical Reference

Reviewed by Melinda Ratini, DO, MS on October 25, 2013

First Aid A-Z

  • There are no topics that begin with 'O'
  • There are no topics that begin with 'Q'
  • There are no topics that begin with 'U'
  • There are no topics that begin with 'X'
  • There are no topics that begin with 'Y'
  • There are no topics that begin with 'Z'

Today on WebMD

Antibiotic on hand
3d scan of fractured skull
Father putting ointment on boy's face
Person taking food from oven

Health Solutions From Our Sponsors

sniffling child
wound care true or false
caring for wounds
Harvest mite

WebMD the app

Get first aid information. Whenever. Wherever... with your iPhone, iPad or Android.

Find Out More