A is for Arsenic: The Structures The Main Suspects A is for Arsenic – Arsenic trioxideB is for Belladonna – AtropineC is for Cyanide – Hydrogen CyanideD is for Digitalis – DigoxinE is for Eserine – EserineH is for Hemlock – ConiineM is for Monkshood – AconitineN is for Nicotine – NicotineO is for Opium – MorphineP is for Phosphorus – White PhosphorusR is for Ricin – RicinS is for Strychnine – StrychnineT is for Thallium – Thallium AcetateV is for Veronal – Veronal Other Structures B is for Belladonna D is for Digitalis H is for Hemlock O is for Opium V is for Veronal