A Spanish Fly is an emerald-green blister beetle, commonly found in southern parts of Europe.
Usually about 16-23 mm long and 5-9 mm wide, it has a strong smell and - if licked - a burning taste. The crushed and dried body of the insect was initially used in medical circles as a diuretic, but later became more commonly known as an aphrodisiac - especially for older men.
The effects of Spanish Fly have long been known, documented by Hippocrates as well as the Romans. The Empress Livia (58BC to 29AD) slipped ground beetle into food ingested by the Imperial Family, solely to cause them to perform sexual acts that - witnessed from hidden viewpoints - would later be used against them.
The name of this beetle is derived from the Greek word for rage, lytta, and the Latin word for blisters, vesica, the combination illustrating the physical effects of a poisonous dose of the beetle; mental illness and blisters.
Due to the beetles' diet it actually contains about 1% of a chemical called Cantharidin. Almost non-soluble in water, it will however, dissolve in most organic oils.
Curiously in Zimbabwe traditional healers sell something named "vuka-vuka", or "WAKE UP!". It consists of nothing more than dried beetles, and locals call it "Squirrels Jump", since these rodents - once consuming a beetle - will do little more than fornicate until the effects wear off.
A critical point to note is toxicity. Ingesting too much Spanish Fly - either knowingly or by subterfuge - may result in a poisoning known as cantharidism, characterised by nephritis and gastrointestinal disturbances. Extreme cases may even result in collapse or death - quite a surprising end to an otherwise lustful evening!
As little as 1.5 grammes of beetle reside have been documented to cause death.
The metabolic byproducts of Cantharidin are well known to irritate the urinary tract during excretion. An irritated urethra increases blood flow to the genitals, and at times results in priapism, or a semi-permanent erection.
As a side note, in 1772 the Marquis de Sade offered cakes doctored with Spanish Fly to prostitutes who were retained for an orgy. A flogging orgy. The girls became so ill as a result of their drug induced frenzy that
the Marquis was brought to trial for poisoning.
At the time of this writing, the only medically recognised use for Cantharidin is to remove genital warts; a solution of 0.7% mixed with acetone is directly applied.
I have no doubt that after such a treatment, those pesky genital warts would just wash right off.