What is cantharidin and how does it remove warts?

Cantharidin is a toxin that comes from beetle juice. It comes from the real bug, it wasn’t just invented for the Tim Burton movie. Cantharidin causes the skin around and under the wart to blister. So as the skin heals, the blister (as well as the wart) peels off. It is usually used in cases when salicylic acid, cryotherapy, or electrosurgery aren’t doing the trick. However, note that it is not well-researched or widely used, and it is not approved by the Food and Drug Administration (FDA).