Tempted to take a cool dip on a scorching day, but deterred by the hordes of jellyfish? Well, you may not have to choose between taking that swim and staying on the beach anymore. There's a cream that's supposed to protect swimmers from jellyfish stings. But does it work? A joint study at Stanford University and the Bert Fish Medical Center put the product to the test.

What the researchers wanted to know: Does a jellyfish lotion live up to its name and keep you from getting stung by jellyfish?

What they did: The study was carried out on 12 people at Stanford University and 12 at Bert Fish Medical Center in New Smyrna Beach, Fla. The 24 brave subjects let the researchers smear Safe Sea, a cream that is supposed to stop jellyfish from stinging you, on one arm and sunscreen on the other. Neither the subjects nor the people applying the cream knew which arm had the cream and which had the sunscreen. Then came the part that required the subjects to be brave: researchers took tentacles from live jellyfish and put them on the volunteers' arms. They tested two different species of jellyfish—one whose sting is just painful and the other's that is very painful and can be life-threatening to small children. Over the next two hours, the subjects reported on the pain, and dermatologists scored inflammation.

What they found: The cream worked on most of the people. It was better on the less dangerous jellyfish; only two of those 12 subjects felt mild pain in the jellyfish-lotion arm, while all 12 had pain and redness in the sunscreen-only arm. But with the nastier jellyfish, three subjects felt pain on the arm with jellyfish lotion, while only 10 felt any pain on the sunscreen arm. Nine had visible reactions on the sunscreen arm, while one arm with the jellyfish lotion had a reaction.

What this study means to you: This is good news for surfers, swimmers, and everyone else who's ever set foot in jellyfish-infested water—and also Nidaria Technologies, the Israeli company that produces Safe Sea lotion and partly funded the study. Now they can claim clinical evidence that their product works.

Caveats: Notice that not everyone got the same benefit from the lotion.

Find out more: Safe Sea is for sale in some drugstores and also at www.safesea.net. The Wilderness Medical Society (www.wms.org) publishes the journal Wilderness and Environmental Medicine, where this study appeared.

Read the article: Kimball, A.B. et al. Efficacy of a Jellyfish Sting Inhibitor in Preventing Jellyfish Stings in Normal Volunteers. Wilderness and Environmental Medicine. June 2004, vol. 15, pp. 102-108.