What is cantharidin?
Cantharidin (C10H12O4) is the lactose of cantharidic acid and the active constituent of cantharides – dried Spanish flies “Lytta vesicatoria”. It has been used as an aphrodisiac and was formerly used as a counter-irritant in plaster form and in small quantities in hair lotions, but is liable to cause nephritis (kidney disease of toxic origin). – from Butterworth’s Medical Dictionary.
