Health

Health is the physical well-being of creatures and heroes in the series. Many creatures have different health values; bigger creatures usually have more health than smaller ones. Once a health value drops to or below 0, the unit will die. The higher a creature's experience level, the more health it can have. Creatures' health is displayed by health flowers.
Health is restored by sleeping, eating, the Heal spell, or (for Imps in Dungeon Keeper) toking. Creatures with the Drain spell can "steal" health from other creatures.
Certain non-creature things (e.g. doors and Dungeon Hearts) also have health. When their health drops to or below 0, it is destroyed. Dungeon Hearts heal themselves, albeit slowly. Doors are damaged permanently. Rooms also have health, which is represented by the red bar on its flag. When their health drops to 0, it is taken over by the "attacking" player. If the health of an individual room slab drops to 0, that slab is destroyed and becomes dirt path.