Nonlethal damage represents harm to a character that is not life-threatening. Unlike normal damage, nonlethal damage is healed quickly with rest.
Dealing Nonlethal Damage
Certain attacks deal nonlethal damage. Other effects, such as heat or being exhausted, also deal nonlethal damage. When you take nonlethal damage, keep a running total of how much you’ve accumulated. Do not deduct the nonlethal damage number from your current hit points. It is not “real” damage. Instead, when your nonlethal damage equals or exceeds half of your current hit points, you’re staggered (see below), and when it exceeds your current hit points, you fall unconscious.
When attacking with weapons, you may freely choose to deal nonlethal damage upon making the attack. However, an attack with a weapon with the nonlethal trait incurs disadvantage when trying to inflict lethal damage.
Staggered and Unconscious
When your nonlethal damage equals or exceeds half of your current hit points, you are staggered, and the number of acts you can take during your turn is reduced by one. You cease being staggered when half of your current hit points once again exceed your nonlethal damage.
When your nonlethal damage exceeds your current hit points, you fall unconscious. While unconscious, you are helpless.
Spellcasters who fall unconscious retain any spellcasting ability they had before going unconscious.
If a creature’s nonlethal damage is equal to his total maximum hit points (not his current hit points), all further nonlethal damage is treated as lethal damage. This does not apply to creatures with regeneration. Such creatures simply accrue additional nonlethal damage, increasing the amount of time they remain unconscious.
Healing Nonlethal Damage
When you rest, you heal nonlethal damage at the rate of 1 hit point per hour per character level. When a spell or ability cures hit point damage, it also removes an equal amount of nonlethal damage.
Burn Damage
Burn damage behaves the same way as nonlethal damage, except that even creatures that are immune to nonlethal damage are affected by burn damage. You suffer burn damage when you overexert to channel more power beyond the limit of what your mind and body can safely endure. Burn damage stacks with nonlethal damage to determine when you are staggered and unconscious. Burn damage cannot be healed by any means other than getting a full night’s rest, at a rate of 1 hit point per hour per character level. When healing from a full night's rest, nonlethal damage is healed first before the burn damage is healed.