When a character takes damage from an attack with a poisoned weapon, touches an item smeared with contact poison, consumes a poisonous substance, inhales a poisonous gas, or is otherwise poisoned, the character must make a Fortitude saving throw. If the character fails, he or she takes the poison’s initial damage (usually ability damage). Even if the character succeeds, he or she typically faces secondary damage 1 minute later. This secondary damage also requires a Fortitude saving throw to avoid.
Poisons are detailed in the Craft (chemical) skill description.
Poisonous liquids are usually administered through injection or by application to a weapon. Poisonous gases must be inhaled to be effective. Poisonous solids are usually ingested with food or drink.
Perils of Using Poison
A character has a 5% chance (roll of 1 on 1d20) to expose him or herself to a poison whenever the character applies it to a weapon or otherwise readies it for use. Additionally, a character who rolls a 1 on an attack roll with a poisoned weapon must succeed at a Reflex saving throw (DC 15) or accidentally poison him or herself with the weapon.
Creatures with natural poison attacks are immune to their own poison. Nonliving creatures and creatures without metabolisms are immune to poison. Oozes and certain kinds of creatures are immune to poison, as detailed in their descriptions, though it is conceivable that a special poison could be synthesized specifically to harm them.