Arsenic

Arsenic is a chemical element with the symbol As and atomic number 33.

Characters poisoned with arsenic

 * Mr Anthony - Accident
 * Alfred Crackenthorpe - 4.50 from Paddington
 * Mr Elsworth - They do it with Mirrors
 * Ashley Ferrars - The Murder of Roger Ackroyd
 * Miss Gilchrist - After the Funeral (self inflicted)
 * Mrs Lydia Horton - Murder is Easy
 * Mrs Albert Jones - The Tuesday Night Club
 * Mr Martingdale - Evil Under the Sun (murder or an accidental overdose)
 * Mrs Oldfield - The Lernean Hydra
 * Mrs Pengelley - The Cornish Mystery
 * Mr Varley? - Dumb Witness