Historically, blister beetles have been used in medicine. Dead and dried beetles were smashed and ground into fine powder. The powder was used to create a seemingly mystic concoction called Spanish fly. People used Spanish fly to treat physical ailments such as arthritis and more salaciously as an aphrodisiac. The basis for these uses is because blister beetles produce cantharidin. The beetles employ the chemical as a means to defend themselves and their eggs. They release the chemical when agitated or attacked by predators. If a person suspects they have been poisoned with cantharidin, medical physicians are able to run diagnostics tests to check for the presence of the chemical in urine and other body fluids.
