The source of this remedy is Cantharis (or Lytta) vesicatoria, a species of beetle misleadingly called Spanish fly, which contains a rapid-acting irritant caged cantharidin. In traditional medicine Spanish fly was used to cause blistering, increase fluid loss, treat baldness, procure abortion and provoke sexual desire. Patients who took it experienced burning pains in the throat and stomach, difficulty swallowing, nausea, vomiting, diarrhoea and a frantic urge to pass water; the unlucky ones went into convulsions, even into a coma.
Constitutional Indications
Cantharis should be the remedy of first resort for individuals who look as if they are suffering intensely.