eamon
Explorer
The PHB covers the normal case of natural healing. A normal dying character can't survive for a day without stabilizing, which is why the section on dying mentions natural healing in the most appropriate section - recovery - which can take a day or more. It does strongly suggest that you do not heal naturally while recovering without help, but doesn't mention the case in which you could naturally heal while not yet stabilized (since this is impossible normally). It does say that a stabilized creature has a 10% chance per day to start healing naturally once more, which almost, but not quite, spells out that you don't heal naturally when unstabilized. It's not hard to extrapolate that an unstabilized creature is worse off than a stabilized creature, so allowing an unstabilized creature to naturally heal "fast" makes no sense unless you also allow a stabilized creature to heal if it has fast healing.
"A creature with the fast healing special quality regains hitpoints at an exceptionally fast rate, usually 1 or more hit points per round, [...]". The exceptional healing ability is exceptional in the rate of healing. The ability does not mention dying in any way, nor recovery therefrom, but does say that it works like natural healing otherwise. Natural healing does not work while recovering unaided, and neither does Fast Healing therefore. The fact that it would exceptionally heal several hitpoints per round doesn't help since the ability isn't functioning at all, since it's no different from natural healing in that respect.
Cheiromancer is correct in saying that Fast Healing doesn't work when dying - i.e. when below 0 hit points.
Unless... you think that a dying creature does heals naturally but stops once he's stabilized. In that case I wish you much luck with a creature that has fast healing 1, and drops to -9. (Do you first roll to stabilize at the beginning of your turn, or first heal fast, at the beginning of your turn?) Once the creature is stable, it stops Fast Healing. Then it has a 10% chance per day to start healing again, but otherwise loses 1 hitpoint per day, (which isn't unstabilizing) which might still kill the creature.
"A creature with the fast healing special quality regains hitpoints at an exceptionally fast rate, usually 1 or more hit points per round, [...]". The exceptional healing ability is exceptional in the rate of healing. The ability does not mention dying in any way, nor recovery therefrom, but does say that it works like natural healing otherwise. Natural healing does not work while recovering unaided, and neither does Fast Healing therefore. The fact that it would exceptionally heal several hitpoints per round doesn't help since the ability isn't functioning at all, since it's no different from natural healing in that respect.
Cheiromancer is correct in saying that Fast Healing doesn't work when dying - i.e. when below 0 hit points.
Unless... you think that a dying creature does heals naturally but stops once he's stabilized. In that case I wish you much luck with a creature that has fast healing 1, and drops to -9. (Do you first roll to stabilize at the beginning of your turn, or first heal fast, at the beginning of your turn?) Once the creature is stable, it stops Fast Healing. Then it has a 10% chance per day to start healing again, but otherwise loses 1 hitpoint per day, (which isn't unstabilizing) which might still kill the creature.