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UH Researchers: Current Jellyfish Sting Recommendations Can Worsen Stings
A sting by this Australian box jelly can lead to death in as little as 5 min. (credit: A Yanagihara)
box jelly with tentacles

A sting by this Australian box jelly can lead to death in as little as 5 minutes. (credit: A Yanagihara)

Being stung by a jellyfish is one of the fastest ways to ruin a fun day at the beach. But what you do after you’re stung has the potential to make you feel much better or make matters a lot worse. Researchers at the University of Hawaiʻi at Mānoa investigated whether commonly recommended first aid actions such as rinsing with seawater or scraping away tentacles lessen the severity of stings from two dangerous box jellyfish species. Their results, published this week in the journal Toxins, reveal that some of the most commonly recommended practices actually worsen stings.

“Anyone who Googles ‘how to treat a jellyfish sting’ will encounter authoritative web articles claiming the best thing to do is rinse the area with seawater, scrape away any remaining tentacles, and then treat the sting with ice,” said Angel Yanagihara, lead author of the paper and assistant research professor at the UH Mānoa Pacific Biosciences Research Center and John A. Burns School of Medicine (JABSOM). “We put those methods to the test in the lab and found they actually make stings much, much worse.”

Box jellies are among the deadliest animals in the oceans responsible for more deaths every year than sharks. Even mild stings cause severe pain and can leave horrible scars.

calm waters in inlet

Cape York, Queensland, Australia, is home to many Australian box jellyfish. (credit: Angel Yanagihara)

Yanagihara, aided by Christie Wilcox, a postdoctoral fellow at JABSOM, looked at the best ways to respond to stings from two dangerous box jelly species, the Hawaiian box jelly Alatina alata here in Hawaiʻi and the largest box jelly in the world, the Australian box jelly Chironex fleckeri. In order to conduct the study, Yanagihara, traveled to Cape York Australia in December 2016 to work on-site with live Chironex. For both, they examined how different ways of removing tentacles—rinsing with vinegar or seawater, scraping with a credit card or simply plucking them off—affected the amount of venom injected during a sting using a human tissue model designed by Yanagihara. They also looked at whether treating with ice packs or hot packs reduced the damage done by the venom.

The most and least effective treatments

The team found that some of the most commonly recommended actions, including rinsing with seawater, scraping the tentacles and applying ice, dramatically increased the severity of the stings. “Less than one percent of stinging cells on a tentacle actually fire when you’re first stung,” explained Wilcox. “So anything you do that moves the tentacles or adherent stinging cell capsules around has the potential to increase the amount of venom injected into you by many fold.”

Instead of rinsing with seawater or scraping, the team found that rinsing with vinegar—which irreversibly prevents the stinging cells from firing—or even simply plucking tentacles off with tweezers led to less venom injection. And after the sting, applying heat actively decreased venom activity. Applying ice not only didn’t help, for stings from the Hawaiian box jelly, it actually enhanced the venom’s activity to make stings cause more than twice the damage. And, if you have it available, the team found the best way to treat a jelly sting was the combination of Sting No More™ Spray and Cream, a venom-inhibiting product duo developed by Yanagihara with Hawaiʻi Community Foundation, National Institutes of Health and Department of Defense funding.

“Box jellies are incredibly dangerous animals. The more venom they inject, the more likely a victim is to suffer severe, even life threatening symptoms,” said Yanagihara. “The increases in venom injection and activity we saw in our study from methods like scraping and applying ice could mean the difference between life and death in a serious box jelly sting.”

“It’s all too easy to find bad advice on treating jelly stings on the internet,” said Wilcox. But she also noted that such bad advice isn’t solely the fault of the sites that provide it. “Even in the peer-reviewed literature, there are a lot of examples of recommendations that are made in passing in discussion sections without any direct evidence to back them up, and then those just keep getting repeated and cited over and over even though they’re not based on rigorous, empirical scientific evidence.”

The team expects these statistically powered findings will prompt online medical sites, government agencies, and the broader medical community to re-evaluate the advice they provide on treating jelly stings. International collaborators and colleagues have joined in this effort and are conducting similar studies around the world using this Yanagihara-Wilcox sting model to test locally prevalent jellyfish species in a similar push to develop evidence-based medical practices.

Sting No More™ (Alatalab Solutions, LLC) was developed under a Department of Defense grant that aimed to rapidly and effectively treat stings in U.S. Special Operations Command combat divers. With the intention of supporting the development of technologies and therapies of benefit to people, the funding required a commercialization plan for resulting products. All testing of the new commercial product, in the current study was performed under an approved University of Hawaiʻi Conflict of Interest plan. This product demonstrates the strongly pro-innovation culture at UH dedicated to bringing to the public sector technologies that have been developed with federal and state research dollars.

This Post Has 18 Comments
  1. Vinegar (or urine) has long been touted as an effective method of jellyfish stings, but has also been discredited by many sources. Good to see it being presented as a scientifically proven remedy. Lifeguards often have a spray bottle available. I am a lifelong ocean swimmer and have had several episodes of box and Man ‘o War stings. I have tried everything, including heat and vinegar, noted in your article without success. Luckily, I have never had a severe reaction beyond local pain and ‘whip’ marks that resolved with ‘tincture of time.’

    My two questions:
    1/ Has this research been retested in different labs with different researchers and peer reviewed? If not, it should be noted as provisional.
    2/ Does it cost money to obtain the noted ‘Spray and Cream’. If so, this is a violation of the research you present.

    Malachy Grange

    1. Aloha Malachy
      Thank you for your comment. I would urge you to download the free, open-access, peer-reviewed study published in the international journal Toxins

      In response to your comments
      1. Vinegar is not a “remedy” or “treatment”; it does not enter the skin or effect venom already in the body. While this has gotten muddled in the popular lay press and on-line, the purpose of vinegar has always been to accomplish part one of a two part first aid approach which is to prevent additional stinging by undischarged cnidae left on the skin after tentacle contact. Anytime a jellyfish tentacle contacts human skin thousands of undischarged cnidae (stinging cell capsules) are left on the skin. These are microscopic and invisible to the naked eye but can be seen under the microscope after taking a sticky tape lift. Vinegar causes the collagen capsule to swell preventing the structural apparatus from firing. Sea water – while sounding innocuous, is not a good choice to remove cnidae. It is not effective in washing the cnidae off of the skin. It simply moves the sticky stinging capsules around without inactivating these “time bomb” venom injecting capsules. At some later time they will fire increasing the over all area of the sting.
      2. Heat not ice will act as a “treatment”. Inactivating venom already in the skin. These venoms are all highly heat sensitive. Safe plumbing hot water 110-115oF 43-45oC for 45 min massively inactivated the venom already injected.
      3. The StingNoMore technologies have been fully commercialized per DOD funding requirement and all work was done under an approved conflict of interest management plan where all data is analyzed by independent authors (not myself).
      4. Yes this work has been replicated by others independently.
      5. As far as studies proporting that vinegar worsens stings or causes cnidae to discharge, please down load and read our paper as a good proportion of the manuscript is devoted to discussing this topic.

      1. Heating at less than 50°C, as shortly as as possible after stinging, using any simple method to heat, (slightly hot plumbing water is not neccessary, a simple hair dryer, hot black paper under the sun, even sun concentrated on the paper with a small lens, hot paper heated by a cigarette or by any thing hot like on a slighly hot stove, a sheet of hot paper has a small heat capacity and thus will not burn even if slightly too hot, contrary to too hot plumbing water at only 60°C, which is very dangerous ) is the best first method to use, proven in many serious scientific studies, on many kind of jelly fish, like the beautiful study by Angel Yanagihara, very useful to show that bad methods increase the severity of stings.
        Personnally I have verified on me and my wife over 15 years, that heating shortly after stnging, with any method ( hot water is not necessary, simply a small hot paper, a hair dryer, anything not too hot ) works by inactivating the venon in the skin and in the remaining tentacles. On usual jellyfishes it is miraculous, stopping any pain with the venon slowly released on several day after, if not inactivated by heat around 45°C ( hair dryer, any hot small sheet of paper, without spending hours waiting for plumbing water, which is not necessary to heat ).

        1. Funny StingNoMore contains acetic acid and water with some other trace chemicals. So does vinegar.

          1. Dear Jeffrey,

            The 15 years of biochemical research into this topic has led to evidence based therapeutics. Some old school approaches have been validated by rigorous research and others have been found to be ineffective or dangerous. First Aid must address 2 specific problems: 1) the presence of thousands of microscopic stinging cnidae left on the skin that like ticking time bombs are still capable of firing to deliver venom and increase the sting severity and 2) inactivate the venom already injected and actively still being injected from discharging cnidae. Acetic acid serves to prevent undischarged cnidae from discharging. If you would like to read about the research involved in this process there are a number of open access peer reviewed papers available on my website. The components of Sting No More Spray are far more effective that vinegar and or urea by themselves. The second step of the process though is the key and that is inactivation of venom already injected into the sting site. Vinegar does nothing to address this. StingNoMore Spray begins to address this but the full bore therapeutic for this is the StingNoMore Cream. My website contains all the MSDS details as well as lay and scientific publications describing these problems and the mechanisms of these interventions. With all due respect, it is certainly not just a random concoction of vinegar, urea and “trace minerals”.

        2. Aloha Gene,

          The website lists current Oahu retail locations as well as has drop down menus for direct web ordering. The products may be available soon at the Four Seasons on Maui. Please inquire with Nico Bonilla 808 874 2243 if you would like to suggest that they carry StingNoMore products.

          Best regards,

  2. My favorite way to supposedly nullify a Portuguese Man of war sting is to rub wet sand on the effected site to remove the vemon. Not sure about this with box jellyfish. As a Floridian, I learned that rubbing dry sugar sand is good for the sting of a Brazilian fire ant. Seems to remove or nullify the vemon.

    1. Aloha Andrew,

      I would like to send out a note of caution with regard to general application of personal experiences. While you genuinely associate a reduction in pain after a Man-o-War (MoW)sting with rubbing of sand onto the site, the body of placebo controlled, statistically-powered data show that MoW sting pain generally rapidly subsides on it’s own and that site pressure or rubbing of any kind actually leads to poorer outcomes. The distracting effect of rubbing the site could be part of the sense of relief but in fact sand does not get into the skin or “remove the venom” at all and data show that rubbing or scraping only causes more adherent stinging cells to fire. In the future, if you were to be stung for instance over 2 separate arms and rubbed sand on one arm verses sprayed vinegar and then soaked the vinegar sprayed sting region in hot water for 45 min ( or used the new technologies that have been developed based on venom research) , then you may have a better sense of the difference of rubbing sand verses vinegar and heat. All in all, though adult men have thick skin (literally) and these are not critical life or death choices. But if a parent mistakenly believes that rubbing sand on the site will ‘nullify … and remove the venom” and does this to a child, the child could become very ill. There have been deaths after Atlantic MoW stings in children. This example is the reason that lab based models are so very important. Anecdotal evidence is very convincing to the individual but may not be representative of hard scientific phenomenology. Please download our free access paper
      and have a look at the various figures especially figure 2. We have another paper under review related to MoW. Please watch this UH site for a news story about that paper when it is published. It will also be free access.

      Best regards,

    2. “dry sugar sand”, hot around 45°C ( 105 to 115F ) under the sun, can work by simply heating and inactivating the venon and really “removing or nullifying the vemon” !
      If cold, it will not work.

  3. Does the recommended treatment (vinegar and tweezer removal with heat) also apply to portugese man of war jellyfish stings?

  4. Thank you so much for your reply which addressed my concerns. I especially appreciate the fact that your research was peer reviewed and found to be accurate. Is there anyway to see this review? Such as in a journal?

    I am not familiar with the DOD reference. My question is: who receives payment for the sale of the product you mention in your article.

    Malachy Grange

  5. In the late 70’s we use to rinse with vinegar to help neutralize the stinging, we then sprinkled a light layer of baking soda to help identify any tentacles, and then removed the tentacles with tweezers. Any time we went to the beach, especially Bellows, those three items were in a zip lock bag.

  6. I was stung by a baby jellyfish in the Tyrrhenian Sea just off the Island of Salina on June 1st of this year. I healed up well (minimal scarring), it took about a month. However I just got injections of Dysport for frown lines on September 8th and noticed a reaction and outline of my jellyfish sting flared up later in the evening. The next day (Sept 9th) I woke up and it was back to its normal baseline with the minimal scarring. I have searched the web looking for a connection of the Dysport causing a delayed reaction but could find nothing. Could there be a correlation between the Dysport and the jellyfish sting since they are both different types of neurotoxins, or was it just a fluke? Is there a possibility I will have further flareups if I receive Dysport again? Thank you for any advice.

  7. Monday, August “lucky” 13th, 2018 —



    I’ve called, by phone, to various water-sports stores around HNL town (and in
    person at “Town & Country,” Kahala Mall) only to be told that none of them carry
    “Sting No More” spray or cream — The closest I got to “success” was that the manager
    at “Go Bananas” kayak shop, across from Safeway on Kapahulu Ave., told me over the
    phone: “We at ‘Go Bananas’ ran out of this product a whole year ago, and we have been
    trying to contact the correct individuals and contacts to get more of the product in —
    but we haven’t heard back for a whole year.” PROFESSOR YANAGIHARA — IS “STING NO
    ON THE INTERNET)? In view of the unexpected influx of Portuguese-men-of-war at
    Oahu’s Yokohama Bay yesterday — as well as the heavy monthly influx of box jellies
    that closed down Hanauma Bay last week — it appears that “Sting No More” is very much in demand, but isn’t available at retail stores. Can anything be done to remedy (pun fully
    Sincerely and Aloha, Professor Emeritus (HPU) Mel Masuda, J.D., M.P.A.


    Given your interview with the Star-Advertiser this past Spring in which you made it clear that ice and cold should NOT be used on jellyfish (box or Portuguese-man-of-war), I was appalled and disappointed to hear, on KSSK Radio News today (Aug. “lucky” 13th), as the news covered the unexpected influx of 60 Portuguese-men-of-war jellyfish at Yokohama Bay on the West side of Oahu, that “it’s recommended that you put ice on the wound.” GOOD GRIEF, AS CHARLIE BROWN SAYS!!! What will it take to get the word out to the media to stop circulating
    such wrong information?!?

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