How to Treat a Jellyfish Sting

Jellyfish stings come from cells called nematocysts, which are found the long tentacles that trail the bell-shaped jellyfish and, in some species, are on the bell itself. These cells inject a protein-based venom.

Severe allergic reactions are the most dangerous reaction to most jellyfish stings. However, some species have strong enough venom to kill you even if you're not allergic to them.

Jellyfish Sting
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When Someone is Stung

The problem with jellyfish is that they sneak up on you. You're cruising along in the ocean one minute, and the next minute, you're feeling the pain of the sting.

Jellyfish tentacles can still sting even after they've been ripped from the creature's body. If you're helping someone who's been stung, you can be stung, too. Try to avoid touching them with bare skin.

Watch for Allergic Reactions

In people who are allergic to jellyfish—and probably have no idea until they're stung—anaphylaxis, a potentially deadly allergic reaction, can cause:

Anaphylaxis can also cause a drop in blood pressure known as anaphylactic shock.

Ibuprofen (Advil, Motrin) and acetaminophen (Tylenol) can help relieve pain. Diphenhydramine (Benadryl) may help with itching, but keep an eye on that as it can be a sign of an allergic reaction.

The Three Steps

Research shows the rapid treatment of jellyfish stings makes a big difference. It can reduce pain, keep systemic symptoms from getting worse, and lower the risk of complications, including infections and a local allergic reaction.

Follow these three steps for treating a jellyfish sting, preferably in order:

  1. Rinse
  2. Pluck off the tentacles
  3. A hot bath

If the species is known to be box jellyfish (Chironex fleckeri) or Irukandji (Carukia barnesi), get emergency medical help immediately.

1

Rinse

The most common recommendation is: Rinse away the tentacles using hot water if possible (see the Hot Bath Step for how hot). If heated water isn't available, use salt water rather than fresh. Freshwater may worsen the stinging pain.

Plain white distilled vinegar (acetic acid)—like you would find in your kitchen—has long been the standard first aid treatment for jellyfish stings. Its use has become controversial in the last few years and several studies leave us questioning whether vinegar really works.

It may depend on the species. A 2017 Irish study of Lion's mane jellyfish stings says seawater rinsing may actually lead to more venom being released into your body while vinegar is safer. Lion's manes are the most problematic jellyfish in that region.

However, when it comes to the bluebottle jellyfish, which live in tropical waters, there's some evidence that vinegar may make bluebottle jellyfish stings worse.

So, if you're going to be in the ocean, it pays to know what kind of jellyfish are common in the area and what recommendations may be specific to them.

Vinegar is still recommended for use on box jellyfish stings. Don't stop rinsing with seawater while somebody is fetching the vinegar, though. Prompt treatment is best.

Should You Pee on It?

One home remedy suggests peeing on the sting. Urine will probably not work on a jellyfish sting and may even make it worse. Some people have reported pain relief, but urine does not always have enough acid to neutralize the venom.

In the cases where urine has worked, rinsing with seawater or hot water may have had a stronger effect on pain reduction. Use hot water whenever possible.

2

Pluck off the Tentacles

Peel off any remaining tentacles with a gloved hand, tweezers if possible, or a stick or shell, in a pinch. Be careful not to get the tentacles on yourself or on your clothing.

If you use bare hands to pluck tentacles off, you'll most likely get stung on the fingers. That's also why it's so important to remove them—if you don't, the person you're helping will keep getting stung until all the nematocysts are used up.

3

A Hot Bath

Immerse the sting in hot water. How hot is hot? Evidence suggests that it should be at least 108 degrees and possibly up to 140 degrees. (Again, there may be some variation depending on species.)

The general rule is to either shower or immerse the sting in the hottest water you can stand. Gradually work up the temperature and be careful not to cause burns.

4

Frequently Asked Questions

How do you treat a jellyfish sting?

Despite what some people may tell you, peeing on a jellyfish sting is unlikely to be of help. Ideally, you would treat a jellyfish sting as follows:

  1. Rinse any tentacles remaining in the skin with hot water. (Cold water may increase the pain.)
  2. Remove the tentacles with a gloved hand or pair of tweezers.
  3. Soak the affected body part in hot water or a hot bath, ideally at around 108 degrees F to 140 degrees F if you can tolerate it.

White vinegar, a traditional remedy for jellyfish stings, may decrease pain with some types of jellyfish and increase pain with others.

What does a jellyfish sting look like?

Jellyfish stings can vary in size depending on the species. They typically cause raised bumps surrounded by reddened (erythematous) skin where the barbed stingers punctured the skin. The bumps may be flesh-colored or be slightly reddish, purplish, or brownish.

Even you don't find any tentacles on you, you can often recognize a jellyfish sting by the track-like "print" that the tentacles leave on the skin.

How do jellyfish sting?

Jellyfish tentacles are covered with microscopic stingers. Each stinger is comprised of a tiny capsule of venom and a coiled tube capped with a puncturing barb.

Jellyfish do not actively seek out food. Instead, their tentacles hang freely from their bag-like bodies and will only sting when they come into contact with prey or predators.

When you brush against a jellyfish, sensors on the surface of the tentacle will cause the capsules to contract and the coiled tube to extend, releasing the venom.

What does a jellyfish sting feel like?

A jellyfish sting is commonly described as being sharp, burning, prickling, or stinging. Oftentimes, the localized sting will be accompanied by a throbbing pain that radiates upward and outward on the arm, leg, or torso.

How long does a jellyfish sting last?

The duration and severity of a jellyfish sting can vary by species. Stings from small bluebottle jellyfish may last for an hour. A sting from the Australian box jellyfish (Chironex fleckeri)—described as the most lethal jellyfish in the world—can be deadly, especially in small children.

A Word From Verywell

Over the years, many of the recommended treatments for jellyfish stings have been supported by very little evidence. Experts are beginning to learn more about what works best, but much of the evidence is preliminary.

This new knowledge has complicated the picture by demonstrating that the stings of different species need to be treated differently, meaning no one set of recommendations will work in all situations.

So, if you're going to be swimming in jellyfish habitat, it's a good idea to know what species are common in the area and what the current recommendations are for that species.

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