How Do Poisons Work?
The rules are not very clear on the exact details of how poisons work. This is an attempt to clear up the order of events involving poison. Please keep in mind that this is our best attempt at an comprehensive set of rules based on the published rules, official errata and blog posts, and posts from designers. Please drop us an email if you find similar evidence that contradicts this.
When you are initially exposed to a poison (whether during your action or someone else's), you must make a save to avoid being poisoned.
Success You resist being poisoned. You do not suffer any ill effects and you need not make any further saves.
Failure You are poisoned and immediately suffer the listed effect. You will need to make further saves to avoid more damage and cure the poison.
Exception If the poison has an onset period, failing the initial check does NOT cause you to suffer any effects.
If you are exposed to more of the same poison at any point while you are poisoned, you need to make a new initial save at +2 DC.
Success You resist the new dose and carry on as if it never happened (this success does not count toward the requisite "consecutive saves" for curing any poison that is already in your system)
Failure The DC for all subsequent checks are increased by 2 and the duration of the poison is increased by half of the listed value. (eg if you are poisoned with a poison with a DC 11, being exposed again forces you to make a save at DC 13. If you fail this, all your future checks to cure the poison, avoid damage, or resist being poisoned again are at DC 13 - and the duration is increased by half. If you are exposed for a third time, you would need to save at DC 15 against the new dose, etc)
For the onset period, nothing happens (if there is no onset, the next step happens right away!)
At the next frequency interval (your next turn for 1/round poisons, 1 minute later for 1/minute, next day for 1/day) you must make a save on your turn (at any point during your turn - you must still make this save if you choose to delay).
Success You suffer no ill effects and now have a save towards curing the poison.
If the poison requires only one save to cure, you are cured and no longer need to make saves.
Failure You suffer the listed effects again.
Repeat the previous step until you fulfill either score enough consecutive saves to cure the poison or the duration runs out.
Poisons with initial and secondary effects
For poisons without an onset, failing the initial save causes you to suffer the initial effect of the poison. The subsequent saves are made against the secondary effect.
For poisons with an onset, failing the initial save causes you to be poisoned but not suffer any ill effect. Failing the first save after the onset causes you suffer the initial effect of the poison. Any subsequent saves are made against the secondary effect.
Special If you are exposed to multiple doses of a poison with initial and secondary effects, you only suffer the initial effect once. Subsequent exposures cause you to suffer the secondary effect and add duration to secondary effects.