Health increases with each level gained, when certain items are equipped, and if certain spells are currently active. Characters and creatures have health correspondent to their level and equipped items. Health can be restored through magic, consuming potions and beverages, or by leveling up. Fast traveling and waiting also fully restore health.
The starting health of the Nerevarine is equal to the sum of Strength and Endurance divided by 2. The Lady birthsign does not affect starting health. The bonus health gain from leveling up is not retroactive. Therefore, it is most advantageous to build up Endurance early on to maximize health. However, future changes in Endurance still affect the base quantity Health. The primary way to permanently increase health is to increase Endurance after leveling up.
Health can be restored through magic, consuming potions and beverages, or by leveling up. Waiting and Resting in a bed or on a bench also fully restores health. Ingredients also restore health and can produce potions that do the same. Unless the ingredient has a health-related effect as its first effect, the ingredient must be first combined with related ingredients via alchemy to make a potion with that effect.
Health can be damaged by various combat means, from magicspells to sword cuts. Potion ingredients and spells can also reproduce these effects. Sources that negatively affect health can either damage health directly, drain health by decreasing its maximum value, or absorb health by siphoning from the target to the caster.