Mithridatism

Overview
Mithridatism is the practice of protecting oneself against a poison by gradually self-administering non-lethal amounts. The word derives from Mithridates VI, the King of Pontus, who so feared being poisoned that he regularly ingested small doses, aiming to develop immunity. Having been defeated by Pompey, legend has it that Mithridates tried to commit suicide using poison but failed because of his immunity and so had to resort to having a mercenary run him through with his sword.

Generally, there is no practical purpose or favorable cost/benefit ratio for performing mithridatism except for people like zoo handlers, researchers, and circus artists who deal closely with venomous animals. Mithridatization has been tried with success in Australia and Brazil and total immunity has been achieved even to multiple bites of extremely venomous cobras and pit vipers. Bill Haast successfully immunized himself to a number of species of venomous snakes.

In fiction
Mithridatism has been used as a plot device in novels, films, and TV shows including, among others, Alexandre Dumas, père's The Count of Monte Cristo; Yoshiaki Kawajiri's Ninja Scroll; Agatha Christie's The Mysterious Affair at Styles; William Goldman's The Princess Bride (and the movie of the same name); and Frisky Dingo.

In poetry
A.E. Housman's "Terence, this is stupid stuff" (originally published in A Shropshire Lad) invokes mithridatism as a metaphor for the benefit that serious poetry brings to the reader. The final section is a poetic rendition of the Mithridates legend.