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What Should I do if I'm Stung by a Jellyfish?

Mary McMahon
Mary McMahon
Mary McMahon
Mary McMahon

A jellyfish is a marine invertebrate that captures and neutralizes its prey with long, trailing tentacles. These tentacles are equipped with nematocysts, small capsules of poison that the jellyfish uses to sting its prey. A sting can be irritating, or it can bring about a life threatening condition. In either case, if you're stung by a jellyfish, get to dry land, gently remove the tentacle, and rinse the area where you were stung with seawater or vinegar.

If you encounter a jellyfish, the first thing to do is to get out of the water. Additional jellyfish may be floating around, and you want to minimize further contact with their venom-laden tentacles. In addition, a patient on dry land is much easier to treat. If a lifeguard is present, notify him or her about the sting. The lifeguard may be able to assist with treatment, and he or she may want to evacuate the water in the area if large numbers of jellyfish have appeared.

Jellyfish swimming in the ocean.
Jellyfish swimming in the ocean.

In many cases, the tentacle will still be attached to the patient. It will actually continue stinging until it is removed, but it must be removed with care. The stinging capsules on the tentacle can rupture if they are not deactivated, increasing the severity of the sting. If you have vinegar available, pour it liberally over the affected area. Seawater will work as well for this, but it is less effective. Next, remove the tentacle, making sure that it does not touch bare skin. Wear gloves, or if gloves are not available, use tweezers, a towel, or even a piece of seaweed.

Jellyfish can wash up onto the shore, posing a hazard to beach-goers who may get stung by stepping on one.
Jellyfish can wash up onto the shore, posing a hazard to beach-goers who may get stung by stepping on one.

Once the tentacle has been removed, the area should be rinsed again with vinegar or seawater. A paste of baking soda can also be applied and left on, or a meat tenderizer can be used, as long as it is left on for less than 15 minutes. After the area has been thoroughly rinsed, check for signs of lesions or hives. Antibiotic ointment can be applied to cuts, while hydrocortisone cream can reduce itching. It may take several weeks for the patient to completely recover after being stung by a jellyfish, but as long as the injured area appears to be looking better every day, it is not a cause for concern.

Baking soda can be good for a jellyfish sting.
Baking soda can be good for a jellyfish sting.

There are a few cases in which someone who has been stung will need emergency medical attention. If the patient is very young, very old, or has severe allergies, take him or her to a medical professional as soon as possible. Vomiting, spasms, difficulty breathing, or an altered level of consciousness are also indicators that someone has received a severely toxic sting. If the person appears to be taking a long time to recover from being stung by a jellyfish, or the symptoms get worse at any point, it is important to take them to a medical provider.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a TheHealthBoard researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a TheHealthBoard researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...

Discussion Comments

anon279880

I was stung today by a group of jellyfish while swimming in Maui, Hawaii. I tried the

vinegar and even urine and nothing has helped, therefore I disagree with the vinegar/urine theory as it made no difference at all. I am in so much pain that its almost debilitating. I am out of my mind in pain and using ice on the affected areas does give a bit of relief.

anon102544

This is for the person inquiring about the jellyfish sting which reappeared. Last year, I was stung pretty badly on about 90 percent of my right leg by a box jellyfish. It took almost a week for all the raised areas and cuts to subside.

But, like clockwork, on the seventh day mark it all flared back up again. The wounds looked fresh, my skin re-bubbled, and it itched terribly. I used anti-allergy meds and kept the area cool. (I believed overheating the area was what caused the flare up). Anyway, after another week the redness went away and has since never come back.

The only residual pain I suffered after that was occasional "pangs" of pain that would be quick and sharp periodically in my leg. This stopped after about two months.

anon101884

My grandson was stung last Friday by a jellyfish and was treated with vinegar from a lifeguard on duty. He had small bumps all over his leg, but they soon went away. Now it's Thursday, almost a week later, and the small bumps have recurred. Does anyone know if this is normal or should I be calling the doctor?

Babalaas

@ GlassAxe- I would like to add another word of caution. Never use fresh water to rinse a jellyfish sting. It can make the pain worse, increase the severity of the sting, and possibly send the victim into shock.

I made the mistake of dumping bottled water on a mild jellyfish sting and it instantly became worse, and the burning stinging pain lasted for a few days. It felt like someone was brushing my ankle with nettle leaves...no fun.

I asked a surfing buddy why my sting was so bad, and he said it was because of the fresh water. He said jellyfish live in seawater, so dumping fresh water on any pieces of tentacle on my leg would have sent the jellyfish nerves in the tentacles into attack mode. Jellyfish would often show up at certain times of the year, so on these occasions I now wear a wet suit for jellyfish sting protection.

GlassAxe

The treatment for jellyfish stings often depends on the type of jellyfish. Vinegar is the best remedy for Box jellyfish; like the deadly ones found in Australia, the non-deadly Hawaiian Variety, and the mauve colored Pelagia Noctiluca found throughout the Mediterranean.

Vinegar will make the sting worse in stings from the Portuguese man-of-war (which actually is not a jellyfish, but a colony of siphonophores) because it will cause unfired nematocysts to fire before it neutralizes the toxins.

The venom from jellyfish and Portuguese man-of-war are proteins, so acids, bases, and heat will neutralize the venom. Since acids and bases will cause the nematocysts to fire in man-of-wars, it is best to apply heat to the area once you have removed the tentacles from the skin. Heat will also help to neutralize the toxins in all other types of Jellyfish stings.

anon55116

The vinegar treatment is in fact very effective. I had read an article in Reader's Digest in the mid- 1990's telling the history of how this antidote was scientifically deduced after researchers studied jellyfish poison.

We were living in Asia at the time and other American friends had a daughter who had been severely scarred by a major jellyfish sting. Shortly thereafter we moved to a location near the sea and our kids would play on the beach frequently. We made it a point to keep a bottle of vinegar handy. It came in handy a number of times and yes, it really works.

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    • Jellyfish swimming in the ocean.
      By: Dmitry Lobanov
      Jellyfish swimming in the ocean.
    • Jellyfish can wash up onto the shore, posing a hazard to beach-goers who may get stung by stepping on one.
      By: Q
      Jellyfish can wash up onto the shore, posing a hazard to beach-goers who may get stung by stepping on one.
    • Baking soda can be good for a jellyfish sting.
      Baking soda can be good for a jellyfish sting.
    • After a jellyfish sting site is rinsed off, that person should be checked for hives.
      By: Jürgen Fälchle
      After a jellyfish sting site is rinsed off, that person should be checked for hives.
    • Rinsing the affected area with vinegar helps alleviate the sting from a jellyfish.
      By: hsagencia
      Rinsing the affected area with vinegar helps alleviate the sting from a jellyfish.
    • Hydrocortisone cream can help alleviate the itching caused by a jellyfish sting.
      By: carroteater
      Hydrocortisone cream can help alleviate the itching caused by a jellyfish sting.