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 your current
hit points, you're staggered, and when it exceeds your current
hit points, you fall unconscious. It doesn't matter whether the nonlethal
damage equals or exceeds your current
hit points because the nonlethal
damage has gone up or because your current
hit points have gone down.
Lethal Damage with a Weapon that Deals Nonlethal Damage: You can use a weapon that deals nonlethal
damage, including an unarmed strike, to deal lethal
damage instead, but you take a -4 penalty on your
attack roll.
Spellcasters who fall unconscious retain any spellcasting ability they had before going unconscious.