If you are watching the soccer World Cup, you have seen the trainers run over to an injured player, spray him with an aerosol can, and then the player magically jumps up and runs back to the game, cured.
What is IN that Magic Spray?
No one knows for sure, but it is likely it is ethyl chloride, a chemical that numbs and freezes the surface of the skin on contact. It is called a “vapocoolant” or skin refrigerant.
Ethyl chloride at the most provides a few minutes of anesthesia. The majority of its effect is likely to be psychological in nature.