There are so many ways that a character can be poisoned: inhalation, ingestion, injection; pretty much every branch of the animal tree has a few poisonous twigs. One can easily poison oneself accidentally. Or perhaps you were poisoned as a result of malice?
If your character has been poisoned and you don't know how, just click the Urk…! Arg! button and let the ill effects commence!
Oh no! You've been poisoned! But I'm not telling you the effects. It's a surprise.