Mithridatism

Mithridatism is a big word that means training your body to be able to handle poison.

Remember when mommy taught you not to eat random things you find, because it might make you sick? Well, some people in olden times thought it would be a good idea to train their bodies by regularly eating or drinking small amounts of poisonous substances (like snake venom or arsenic) so that if they accidentally got poisoned, their body would know what to do and they wouldn't get as sick. Kind of like practicing for a test!

But this is a really dangerous thing to try and do on your own because these poisons can be deadly, so most people shouldn't even think about it! It's better to just stay away from things that can hurt you instead.