text: Cantharidin, the principal active component in preparations of Lytta vesicatoria-derived Spanish fly, was first isolated and named in 1810 by Pierre Robiquet, a French chemist living in Paris, who demonstrated that it was the principle responsible for the aggressively blistering properties of this insect's egg coating; toxicity comparable in degree to that of the most violent poisons known in the 19th century, such as strychnine, was asserted.