Regeneration and healing are very limited in HND, especially in combat. Natural, unassisted regeneration is very slow. Players who take extensive wounds will not magically heal in a few minutes as they walk around.
Bandaging and herbs are extremely important methods of health recovery. There are no healing potions. Bandaging and herbs can stop bleeding and more quickly heal wounds or increase hitpoint regeneration.
Bleeding is a very serious effect in HND. It plays the role of most of the DOT(damage over time)'s in the game. Damaging a specific body part extensively will cause bleeding. Critical hits can occasionally cause bleeding prematurely to a low-damage body part. Bleeding continues until the blood clots, or, in the case of more serious wounds, the wound is bandaged. Bleeding damage can kill. Extensive bleeding causes a loss of both stamina and hit points.
Once all bleeding is stopped and wounds are bandaged, the player is able to enter an immobile meditation/prayer state to more quickly recover lost hit points. However, some major wounds cannot be healed in this manner.
Another method of healing comes from Prayers. An advanced healer works mostly out of combat, and combines bandages, herbs, and prayers. This is also an NPC profession, but most NPCs will charge very high prices to allow for very easy player competition.
In combat, there will be extremely low regeneration and very little healing, except for occasional battle prayers. Players can also duck out of battle, behind a tree or a rock, to bandage a bleeding wound. No potions, big regeneration, or "heals" in combat, however.
Similarly, poisons require antidotes or herbs to delay their effects. A "cure poison" type effect is extremely rare, limited to only the most pious users of the Prayers skill tree.