Avid watchers of the World Cup soccer tournament have seen the same peculiar scene over and over again: Team doctors tend to an injured player by dousing his wound with a so-called magic spray. Moments later he's on his feet and racing down the pitch. What is this magic spray, and where can I get some?
It could be anything. Trainers might resort to any of several remedies for an on-field treatment, all of which can come out of a spray can or bottle. They might use cold water, for example, to cool off an overheated athlete. Or they might spray an abrasion with a tincture of benzoin so they can stick a bandage on some sweaty skin. It's safe to assume that some magic spray cans contain "skin refrigerants," chemicals like ethyl chloride that freeze and numb the surface of the skin on contact.
Skin refrigerants are easy to order online—a few bucks will get you a small can of a dimethyl ether "coolant cold spray"—but they may not help your injury very much. Some trainers don't bother with cold sprays, arguing that they provide at most a few minutes of anesthesia. That's enough to help you out if you're at the doctor's office and you're about to get a shot. But it's not going to do much for your dinged knee over the course of a soccer match. The cold spray's proponents say it can have positive psychological effects, and that it is most effective for injuries that cause a lot of pain over a short period of time, like a badly stubbed toe.
For fans, the phrase "magic spray" refers to the potion's impossible restorative powers. If the magic spray "works," the player probably took a dive and faked his injury. Magical soccer cure-alls are nothing new. The sprays are in vogue now, but the team docs used to treat phantom injuries with something called the "magic sponge."
Magic spray may be an invention of professional soccer, but skin refrigerants have been around for a long time. In the mid-1860s, a doctor named Benjamin Richardson developed the first aerosol to be used as a cooling anesthetic. The Nation printed an account of his magic spray can in May of 1866: "By employing in this instrument some highly volatile liquid, like ether, and throwing this out as a volume of fine spray, there would be produced, by the evaporation of the ether, such intense cold as would quickly benumb, and so render insensible to pain, any small portion of the human body that might be subjected to it."
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Explainer thanks Jon Schriner of the American College of Sports Medicine.