The Spanish fly has been notorious since the Middle Ages because its poison is both deadly and curative. What is the Spanish fly and what are its magical powers?

 

The Spanish fly (lat. Cantharis vesicatoria) is a metallic green shimmering oil beetle. It grows up to 2 cm long. Since the Middle Ages, the Spanish fly has been said to have a potency-enhancing effect; the beetles were dried and ground into powder.

However, science has not been able to confirm this theory.

 

The body of the Spanish fly contains a toxin (cantharidin) which is a strong irritant and can lead to kidney failure if taken orally. Only about 0.03 g of cantharidin are lethal to humans.

 

The venom of the Spanish fly is used externally in natural medicine for the treatment of a number of ailments. Plasters sprinkled with cantharidin treat rheumatic and arthritic diseases, inflammations, neurodermatitis and gout.

The secretion under the patch stimulates the body's defences and helps the body to heal itself.