Merely touching this type of poison necessitates a saving throw. It can be actively delivered via a weapon or touch attack. Even if a creature has sufficient damage reduction to avoid taking any damage from the attack, the poison can still affect it. A chest or other object can be smeared with contact poison as part of a trap.
Ingested
Ingested poisons are virtually impossible to utilize in a combat situation. A poisoner could administer a potion to an unconscious creature or attempt to dupe someone into drinking or eating something poisoned. Assassins and other characters tend to use ingested poisons outside of combat
Inhaled
Inhaled poisons are usually contained in fragile vials or eggshells. They can be thrown as a ranged attack with a range increment of 10 feet. When it strikes a hard surface (or is struck hard), the container releases its poison. One dose spreads to fill the volume of a 10-foot cube. Each creature within the area must make a saving throw. (Holding one's breath is ineffective against inhaled poisons; they affect the nasal membranes, tear ducts, and other parts of the body.)
Injury
This poison must be delivered through a wound. If a creature has sufficient damage reduction to avoid taking any damage form the attack, the poison does not affect it. Traps that cause damage from weapons, needles, and the like sometimes contain injury poisons.
Perils of Using Poison
A character has 5% chance of exposing himself to a poison whenever he applies it to a weapon (standard action). Once applied, the poison remains potent for 1 minute before drying. Additionally, a character who rolls a natural 1 on an attack roll with a poisoned weapon must make a DC 15 Reflex save or accidentally poison himself with the weapon.
