A temporary loss of 1 or more ability score points. Lost points return at a rate of 1 point per day unless noted otherwise by the condition dealing the damage. A character with Strength 0 falls to the ground and is helpless. A character with Dexterity 0 is paralyzed. A character with Constitution 0 is dead. A character with Intelligence, Wisdom, or Charisma 0 is unconscious.
If a creature has an attack that deals ability damage, the creature's descriptive text gives the ability and the amount of damage. If an attack that causes ability damage scores a critical hit, it deals twice the indicated amount of damage (if the damage is expressed as a die range, roll two dice). Ability damage returns at the rate of 1 point per day for each affected ability.