Guides
Jellyfish sting in Puerto Rico: what to do, including man o' war stings
For a jellyfish sting in Puerto Rico, rinse the area with plenty of household vinegar for at least 30 seconds; if you have no vinegar, wash it with seawater. Don't rub it with sand, press or scrape it. Then soak the area in hot tap water, 107 °F to 115 °F, for 20 to 40 minutes. Get help right away if pain increases or you have trouble breathing.
Is it an emergency? Call 911.
Is this an emergency?
This is not an emergency service. Call 911 or go to the nearest emergency room if you have:
- Trouble breathing
- Chest pain or changes in pulse
- Fainting or collapse
- Pain that keeps getting worse
- Belly pain, cramps or strong muscle spasms after a sting
Help lines
First aid for a jellyfish sting in Puerto Rico
These are the steps from MedlinePlus, published by the U.S. National Library of Medicine:
- Rinse the sting site with large amounts of household vinegar for at least 30 seconds. According to MedlinePlus, vinegar rapidly stops the thousands of tiny stinging cells that have not yet fired.
- If vinegar is not available, wash the sting site with ocean water.
- Then soak the area in hot tap water at 107 °F to 115 °F (42 °C to 46 °C), not scalding, for 20 to 40 minutes.
- Afterwards you can apply an antihistamine or steroid cream, such as cortisone cream.
What not to do
MedlinePlus says to protect the affected area and not rub sand on it, apply pressure or scrape the sting site. Don't use remedies that aren't in these instructions. If you are unsure, call Poison Help at 1-800-222-1222, which also serves Puerto Rico.
Portuguese man o' war stings in Puerto Rico
The Portuguese man o' war looks like a jellyfish, but according to NOAA it is a siphonophore, a close relative. You can recognize its balloon-like float, which may be blue, violet or pink, and its long tentacles, which average about 30 feet.
It lives mostly in tropical and subtropical seas. Its sting is rarely deadly, but it is very painful and causes welts. It can still sting weeks after washing ashore, so don't touch any you see on the sand, and teach children not to touch them.
MedlinePlus gives the same first aid for all types of jellyfish.
Signs of a more serious reaction
Most stings cause pain, burning and welts on the skin. According to MedlinePlus, a Portuguese man-of-war sting can also cause belly pain, changes in pulse, chest pain, chills, headache, muscle pain and spasms, numbness, sweating and, in severe cases, collapse.
MedlinePlus says to get medical attention right away if pain increases or there are any signs of breathing difficulty or chest pain. In that case, call 911. See also when to go to the ER.
How we help by video
For stings that aren't emergencies, we offer virtual urgent care. In a US$79 doctor visit, Dr. Diana Nieves Castro, MD, a Puerto Rico-licensed general practice physician with several years of emergency-department experience, looks at the sting, evaluates pain, itching or swelling, and checks for signs of infection in the days after. If appropriate, the doctor prescribes and we send your prescription to your pharmacy. We do not prescribe controlled substances.
Request a visit online 24/7 — we confirm your time by email or text. We send you a secure video link; it works on your phone, tablet or computer. You must be in Puerto Rico during the visit, and visitors are welcome. More on virtual urgent care.
If you have any sign of a serious reaction, don't wait for a video visit: call 911 or go to the ER. See ER vs urgent care in San Juan.
Jellyfish stings in children
Children get the same first aid. Test the hot water with your own hand before soaking your child's skin, so you don't scald them. If your child has any of the serious-reaction signs on this page, call 911. We see children of all ages; if the patient is under 21, a parent with patria potestad or a legal guardian stays on the video for the whole visit and shows photo ID.
Before you go to the beach
Check the National Weather Service San Juan beach forecast, which reports rip current risk and the UV index, and follow the flags and lifeguards. There are area guides for beaches such as Isla Verde and Condado. On vacation? See also sick on vacation in Puerto Rico.
If you get an itchy, stinging rash where your swimsuit touches your skin after swimming, it may be seabather’s eruption, an allergic reaction to the larvae of jellyfish or sea anemones. And if the shore has piles of sargassum, read sargassum health effects.
How we care for you
We evaluate, diagnose and treat; if needed, we give you a lab order for a lab near you.
We see adults and children of all ages. Patients under 21: a parent with patria potestad (parental authority) or a legal guardian is on camera for the whole visit and shows photo ID.
Real-time video visit. We send you a secure video link. It works on your phone, tablet or computer.
If appropriate, the doctor prescribes and we send your prescription to your pharmacy. We do not prescribe controlled substances.
You must be physically in Puerto Rico during the visit (visitors, tourists and cruise passengers are welcome).
In an emergency, call 911.
Frequently asked questions
What should I do right after a jellyfish sting?
Can a man o' war on the beach still sting?
When should I go to the ER for a sting?
Can a doctor look at my sting by video?
About this page
Author: The Health Initiative
Medical care provided by Dr. Diana Nieves Castro, MD (PR license 24027)
Disclosure: Founding Executive Director of The Health Initiative
Published: 2026-09-30 · Updated: 2026-10-02
Sources (4)
- Jellyfish stings (MedlinePlus, U.S. National Library of Medicine) (opens in a new tab) (accessed 2026-09-30)
- What is a Portuguese man o' war? (NOAA) (opens in a new tab) (accessed 2026-09-30)
- Beach forecast, San Juan (National Weather Service) (opens in a new tab) (accessed 2026-09-30)
- Jellyfish stings and seabather's eruption (Merck Manual) (opens in a new tab) (accessed 2026-10-02)
