3e SRD:Stabilize Self Skill
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A character can attempt to subconsciously prevent him or herself from dying. If the character has negative hit points and are losing hit points (at 1 per round, 1 per hour, or 1 per day), he or she can substitute a Stabilize Self check (DC 15) for his or her first normal stabilization roll to become stable. If successful, the character regains no hit points, but does stop losing them. If the first Stabilize Self check is unsuccessful, the character goes back to making normal stabilization checks each round.