The pharmacologic potential of the substance, cantharides, has been known for thousands of years. This crude concoction is produced by grinding dried blister beetles. The best known blister beetle is Cantharis vesicatoria, or the Spanish fly. The agent responsible for cantharides' physiologic effects is the chemical, cantharidin. One of the many consequences of cantharidin ingestion is priapism. This finding has caused many to mistakenly assume that cantharides, or rather "Spanish fly," is an aphrodisiac. While the substance may in fact cause priapism, its primary pharmacologic effects are actually those of a potent toxin.
People have used Cantharides powder since at least the time of Hippocrates (10:33). In fact, Hippocrates himself recommended it for the treatment of dropsy. During the Greco Roman period cantharides was also used to treat pleurisy, pericarditis, and amenorrhea (11:444). Perhaps it was during its employment as a therapeutic agent that the powder's effects on the genitourinary tract were first noticed. The active ingredient of cantharides, cantharidin, is a potent irritant. In nearly toxic doses, its irritant effects cause priapism (permanent erection) in men, and pelvic congestion (with occasional uterine bleeding) in women. Through the ages these physiologic findings may have been misinterpreted as increased sexuality.
Cantharides use as a love potion is well rooted in folklore (7:591). As far back as the first century, the powder was advocated as an aphrodisiac by the Greek army physician, Dioscorides. During the 18th century, cantharides use was widespread. The concoction reputedly helped Louis XV and Ferdinand the Catholic overcome their "conjugal disinterests" (7:591).
Since the Spanish fly is native to southern Europe, cantharides may have originally been derived from Cantharis vesicatoria (11:444). Blister beetles belong to the order Coleoptera (7:592). These insects are ...