Florida jellyfish and man-of-war stings: first aid, symptoms, and what to avoid

Stung right now

The American Red Cross jellyfish page also says to call 911 when any of these are true:

• Nobody knows what stung the person.
• The sting is on the face or neck.
• The person has a history of allergy to a marine sting.
• The animal is a known lethal jellyfish.
• The person shows signs of shock or a severe allergic reaction, including trouble breathing.

If the person is alert, breathing normally, and the sting is on a limited patch of skin, get a lifeguard. For sting advice when there is no immediate emergency, call Poison Control at 1-800-222-1222. Florida's poison centers answer that number and take marine-sting calls. Tell them the beach, the time, the symptoms, and what has already been put on the skin.

What to do for a localized sting

These steps follow the current Red Cross jellyfish page for a person who is out of the emergency list above. Palm Beach County publishes its own lifeguard steps, including vinegar. Those are in the next section. Do not mix several liquids while you wait.

1. Get out of the water. Tell a lifeguard. Do not keep swimming through the pain. Anyone helping should avoid the loose tentacles.
2. Lift visible tentacles off the skin. The Red Cross says to use a gloved hand, a hand inside a plastic bag, a towel, a blunt stick, or a plastic utensil. CDC says forceps or the edge of a plastic card can also lift them off. Do not rub the skin with the towel, and do not grind sand into it. Bare fingers can get stung too.
3. Rinse with seawater, not fresh water, while stinging material is still on the skin. CDC says a fresh-water rinse can make more stinging cells fire. Use seawater gently. Do not scrub.
4. Then use hot water for the pain. The Red Cross says to immerse the skin in water as hot as the person can stand, without scalding, for at least 20 minutes or until the pain eases. If there is no hot water, a chemical heat pack, or a hot item such as a hot rock or wrapped sand, can be used inside a thin dry towel. Do not rub. Do not wrap the sting in a tight elastic bandage.
5. Keep watching. Skin pain getting better does not cancel new trouble breathing, fainting, vomiting, or chest symptoms. Those go back to 911.

If a heat source is missing, or after the heat, the Red Cross says lidocaine gel may be used when it is available. This page does not give a dose. A child needs an adult to test the hot water first. Stop if the skin hurts in a new way or looks burned. Do not chase the hottest number you can find.

CDC describes a hotter measured soak, about 113°F (45°C) for about 20 minutes, and says the benefit is not well proven. The same CDC page says an ice pack can ease a mild sting. The Red Cross consumer steps use heat, not ice. Both pages are current. Heat is for pain after the tentacles are off. It does not treat a severe allergic reaction.

A sting in the eye or the mouth needs medical care. Do not rub the eye. Do not pour vinegar or hot water into the eye. Skin steps are not eye steps.

A stingray, sea urchin, or spiny fish is a different injury. The Red Cross says to flush that wound with tap water or ocean water, keep the part still, soak it in water as hot as the person can tolerate for at least 20 minutes or until the pain goes away, and ask a clinician about a tetanus shot. Do not use this page's jellyfish debate for a spine left in the foot.

Why vinegar advice does not match

There is no one rinse that every official page endorses for every Florida sting. The conflict is in the sources. It is not just a beach rumor.

Remedies to skip

A man-of-war is not a jellyfish

The Florida Museum says the Portuguese man-of-war, Physalia physalis, is a siphonophore. It is a colony of specialized animals, called zooids, that work as one. It is not a true jellyfish. CDC places it with the hydroids, in the same broad stinging group as fire coral, jellyfish, and sea anemones.

The float is blue, purple, or pink and can look like a balloon or a blue plastic bag. Palm Beach County warns that a curious person who picks it up or pops it can get a painful sting. The float sits on the water. The tentacles hang below it, so a swimmer can meet a tentacle without touching the float.

Length is not one number. The Florida Museum says tentacles are typically around 30 feet and can sometimes stretch more than 100 feet. Palm Beach County, citing National Geographic, says they can extend 165 feet and that 30 feet is the more common average. Both pages agree the trail is long. Do not swim between visible floats and assume the gap is clear.

The animal drifts with wind and current. It is not chasing swimmers. The museum says it lives in every ocean except the Arctic, often washes up on Florida coasts, and can float in groups of more than 1,000. In the Pacific the same animals are often called bluebottles and are usually smaller. The museum says Atlantic and Pacific animals are currently treated as one species, with genetic work that may show more than one.

A dead colony can still sting. The museum says the sting is a reflex. A severed tentacle in the water or on the sand can fire. Palm Beach County says the same about a dead animal on the shore. Do not pop the float, and do not pick one up for a photo. Teach children that a blue or purple "balloon" on the beach may be an animal with tentacles.

Sea slugs in the genus Glaucus eat men-of-war and keep the stinging cells. The Florida Museum says touching one can sting as hard as touching a man-of-war. Leave a small bright blue slug on the sand alone.

Florida's poison centers also name the upside-down jellyfish and the lion's mane jellyfish, along with the man-of-war, as animals whose stinging cells can cause serious pain and scarring if the sting is handled the wrong way. This page does not try to identify those animals from a phone photo. Pain and breathing matter more than the name.

CDC describes the Australian box jellyfish, Chironex fleckeri, as a separate animal of the southwestern Pacific, northern Australia, Malaysia, and New Guinea. It is not the ordinary float on a Florida beach. A bad reaction still needs care. Do not spend the emergency arguing about the species.

What a sting feels like

CDC says many of these stings cause a painful, itching rash and are not usually a severe illness. Some are. Palm Beach County says a man-of-war sting is often fiercely painful, leaves whip-like red welts, and is rarely deadly. The county says the welts often last 2 or 3 days, the pain often stays in the stung area and can last up to an hour, and the pain sometimes travels. Serious effects on their page include chest tightness, trouble breathing, stomach cramps, nausea, vomiting, and shock. Those need immediate medical care.

The county says young children, older adults, and people who react badly to bee stings or other insect stings are more likely to get the serious symptoms. The Florida poison-center page lists shock, vomiting, diarrhea, headache, muscle spasms, chest or abdominal pain, and chills among possible symptoms. A welt does not prove which animal it was. Tell the clinician what you saw.

Do not use "rarely deadly" or "the pain lasts an hour" as a reason to wait through worsening symptoms. New trouble breathing, a spreading illness, or a child who looks very sick needs care now.

After the immediate steps, Palm Beach County says a lasting itch or rash can be taken to a pharmacist, who may suggest hydrocortisone ointment or an antihistamine. Follow the package age limits. Do not put those products in an eye. Itch medicine is not care for trouble breathing.

The itch under a swimsuit

A rash that shows up mainly under a swimsuit can be seabather's eruption. People call it sea lice. It is not a person-to-person lice infection.

CDC says it is a rash from cnidarian larvae trapped against the skin, for example under a bathing suit. Palm Beach County says the cause there is miniature jellyfish larvae trapped under suits, T-shirts, and even hair. Pressure from sitting, a board, or lying on the sand can make the stinging cells fire. The county says some people feel a prickle in the water. Itching usually starts several hours later, often lasts 2 to 4 days, and can last as long as two weeks. Headache, fever, or nausea can happen. The county says signs are posted on its beaches when sea lice are present.

Leave the water. Take the swimsuit off before the shower. Showering in the suit can set off more stings. Do not rub. Wash the suit with detergent and dry it with heat before it is worn again. The county says treatments that ease itch can help, including an antihistamine or cortisone cream, and a severe reaction should go to a physician. This page does not give a dose.

The same county page describes a different rash, swimmer's itch, as a mild allergic rash from parasites that leave snails and burrow into skin, most often in summer. It is not the same as a tentacle welt and not the same as seabather's eruption. A clinician sorts a rash that does not match the beach story.

When they show up, and what a purple flag means

There is no single Florida month when every stinging animal appears or leaves. Palm Beach County says men-of-war on its coast are mostly present from November through April, when strong east winds carry them in. The same county says the jellyfish stings it describes are more common in the warmer summer months. Those are that county's patterns, not a forecast for every beach. A winter visitor can still meet a man-of-war. A summer day can still be clear.

The Florida Museum says men-of-war wash up on Florida's coasts. A Gulf beach is not a promise of safety, and an Atlantic beach is not the only place they strand.

Volusia County publishes the flag colors used under Florida's uniform warning program:

• Green: low hazard, calm conditions, still use caution.
• Yellow: medium hazard, moderate surf and/or currents.
• Red: high hazard, high surf and/or strong currents.
• Double red: water closed to the public.
• Purple: dangerous marine life spotted.

Volusia County says the absence of flags does not mean the water is safe, and that public beaches using a warning system must follow the state program. Palm Beach County says the purple flag flies on lifeguard towers when men-of-war are present, and that a marine-life flag can fly with another flag. Purple is not a surf report and not a treatment instruction. Ask the lifeguard what was seen and whether people are being told to stay out.

How to lower the chance of a sting

• Pick a guarded beach and ask about the water before you go in.
• If a purple flag is up, believe it. Tentacles can reach past the float you see.
• Do not touch a blue, purple, or pink float, a blob of jelly, or a small bright blue slug. Dead still counts.
• Keep children off stranded animals. One rule is enough: do not touch jellyfish or blue balloons on the beach, even when they are not moving.
• Covering skin can mean less bare skin in the water. A suit can also trap the larvae that cause seabather's eruption. If stinging starts under the suit, get out and take the suit off before you shower.
• Do not use sunscreen as a reason to swim through a line of animals.
• Keep dogs off stranded animals. If a dog mouths one, call a veterinarian. This page does not give a dose of a human medicine for a dog.

A small beach kit can hold tweezers, a pair of gloves or a plastic bag, and a phone with 1-800-222-1222 saved. Write down the beach access name when you arrive. The kit does not replace a lifeguard or 911.

Beach days also raise other Florida questions. The beaches page, the surf page, and the venom page sit next to this one. A tick in the dunes is a different bite. That guide is the Florida ticks page.

Questions

Does peeing on a jellyfish sting help?

No. Do not use urine. CDC says urine and alcohol are not recommended. Florida's poison centers also say their sting advice does not include urinating on the person.

Can a dead Portuguese man-of-war still sting?

Yes. The Florida Museum says the sting is a reflex, so a severed tentacle in the water or on the beach can still sting. Palm Beach County says a dead man-of-war on the shore can still sting. Do not pick one up.

Should vinegar go on every Florida sting?

No. CDC says vinegar may stop further stinging in some Indo-Pacific species and may increase it in some species around the United States. The Florida Museum says a vinegar rinse can inactivate a man-of-war's stinging cells. Palm Beach County lifeguards treat the stings they see with plain distilled vinegar. The current Red Cross steps do not list vinegar. On a staffed beach, let the lifeguard treat the sting. If there is no emergency and no lifeguard, call Poison Control before pouring on a remedy.

Does every sting need an ambulance?

No. The Red Cross says to call 911 for trouble breathing, shock, a severe allergic reaction, a sting on the face or neck, a history of allergy to a marine sting, a known lethal jellyfish, or a sting when nobody knows what animal did it. A person who is alert, breathing normally, and has a localized sting can get lifeguard care or call Poison Control at 1-800-222-1222.

Can a rash show up under a swimsuit when no jellyfish was seen?

Yes. CDC calls this seabather's eruption, a rash from larvae trapped under a bathing suit. Palm Beach County says to take the suit off before showering, then wash it with detergent and dry it with heat. Itching can start hours later.

Sources

Checked November 6, 2026. Where the Red Cross, CDC, the Florida Museum, Palm Beach County, and Florida's poison centers do not match, this page keeps the difference. A physician has not reviewed this page. Corrections go through the This Is Florida contact page.

• American Red Cross, jellyfish stings first aid
• CDC Yellow Book, 2026 edition, poisonings and envenomations, marine animals, page dated April 23, 2025
• Florida Museum of Natural History, five facts on the Portuguese man-of-war
• Palm Beach County Parks and Recreation, beach hazards, including man-of-war, jellyfish, and sea lice
• Florida's Poison Control Centers, aquatic toxins
• Volusia County Beach Safety, beach warning flags

This Is Florida does not diagnose stings, rashes, or allergic reactions. A clinician does.