We are being poisoned. Willingly, unwillingly and sometimes more than willingly. For a doctor, the diagnosis of any poisoning is an uncommon one to make. But thrilling nevertheless, when accurately done, as it  rarely figures at the top of the list of a differential diagnoses. The doctor then is suddenly transformed from a cap mask wearing medico, to a deerstalker hat-wearing detective. Here I recall an interesting case that was diagnosed by chance events.