Healing is an ability a Thaumaturge has. It is the ability to heal injuries and wounds. Normally, a Caster doesn't get this power unless they're a Thaumaturge. When someone is hurt, a Thaumaturge usually is able to just touch them per-say and they're healed. When a Thaumaturge heals a person, their hands radiate warmth and the warmth spreads all across their bodies.
Ryan Duchannes was able to heal Ethan Wate and Lena Duchannes. Emmaline Duchannes duplicated Ryan's power to heal Mrs. Lincoln and Macon. John Breed gained this power after bumping into a random Thaumaturge with his power absorption and was able to heal Liv. Alicia was brought in to heal Ridley.