Taking the Sting Out of Jellyfish Stings

By Ellen Kuwana
Neuroscience for Kids Staff Writer
June 25, 2004

Jellyfish used in the study:

  1. Stinging Nettles (Chrysaora fuscescens)
    • Habitat: Chesapeake Bay, Pacific Ocean from Alaska to S. California, Atlantic Ocean from Massachusetts to Florida, Gulf of Mexico
    • Sting: causes burning feeling, swelling, pain and blisters
  2. Box Jelly (also known as the Sea Wasp Chiropsalmus quadrumanus)
    • Habitat: Florida and Texas coasts, Gulf of Mexico, Pacific Ocean near northern Australia, Philippines
    • Sting: same symptoms as stinging nettles, but more severe reactions; can cause death in small children

In the movie "Finding Nemo," fish bounce off the bell-shaped tops of the jellyfish to move through them safely; humans are not so agile -- we usually collide with jellyfish, suffering painful stings on our legs or arms. Jellyfish use a barb-like structure called a nematocyst to inject toxin when they contact us. This toxin results in a burning sensation and reddened skin.

A study led by researchers at Stanford University compared sunscreen to a cream made in Israel called Safe Sea. Safe Sea is an over-the-counter cream that contains sunscreen and ingredients that are supposed to make jellyfish stings less painful.

Experimental Design

Twenty-four volunteers agreed to have their arms stung by either stinging nettles or the more painful box jelly (see jellyfish information in box at right). On each test subject, one arm was covered in sunscreen and the other arm was covered in the sting-inhibitor cream. Next, wet jellyfish tentacles were placed on each arm for up to a minute. Dermatologists (skin doctors) then examined the subjects' arms every 15 minutes for two hours. The dermatologists did not know which arm had been treated with the sting-inhibitor cream. They noted how red the stings were, and recorded how much pain each subject reported.

Sea Nettle Test Results

Twelve subjects were stung by the sea nettles. For the arm which had sunscreen only, all 12 of the test subjects reported discomfort and all had swelling and redness from the stings. On the arm that had the sting-inhibitor cream, two of the 12 test subjects reported "mild discomfort," and none had redness or swelling.

Box Jelly Test Results

For the 12 who went arm-to-tentacle with the fiercer box jelly, the arm with the sting-inhibitor cream fared better. For the arm that had suncreen only, 10 out of 12 test subjects reported discomfort and nine of the 12 showed swelling and redness from the stings. For the arm that had the sting-inhibitor cream, three out of the 12 reported discomfort and only one showed the redness and swelling of a sting.

Although the cream was not 100% effective, it did offer some degree of protection. The researchers conclude that Safe Sea does reduce the "frequency and severity" of the stings. The next questions that need to be answered are how it performs in the open water (i.e., the ocean) and how often it should be reapplied.

Did you know?

 That's a fast sting! The box jelly stings with acceleration of up to 40,000 times the force of gravity. The toxin enters the skin within a fraction of second, making the jellyfish sting one of the fastest mechanical events observed in nature. (Source: Wilderness and Environmental Medicine, 15, 102-108, 2004.)

Neuroscience for Kids does not endorse any specific products. The research mentioned in this article was funded in part by the makers of SafeSea. One of the authors of the research study (see below) used the product five years ago. He is a researcher at Stanford University and is a consultant to the company that makes SafeSea.

References and Further Information:

  1. Kimball, A.B., Arambula, K.Z., Stauffer, A.R., Levy, V., Davis, V.W., Liu, M., Rehmus, W.E., Lotan, A. and Auerbach, P.S., Efficacy of a Jellyfish Sting Inhibitor in Preventing Jellyfish Stings in Normal Volunteers, Wilderness and Environmental Medicine, 15:102-108, 2004.

  2. Cream May Ward Off Jellyfish Stings, Stanford Study Suggests, Stanford School of Medicine Press Release, June 1, 2004.

  3. "Prevention: Jellyfish Stings for a Good Cause," by Eric Nagourney, The New York Times, June 15, 2004.

  4. Beware of the Irukandji Jellyfish from Neuroscience for Kids.

  5. General information about jellyfish including what to do if stung.

  6. All sea nettle photographs on this page were taken by Mary Hollinger of the National Oceanic and Atmospheric Administration.

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