The term substance, when discussed in the context of substance abuse and dependence, refers to medications, drugs of abuse, and toxins. These substances have an intoxicating effect, desired by the user, which can have either stimulating (speeding up) or depressive/sedating (slowing down) effects on the body.
Definition of heal. 1  transitive verb. 2  1a : to make free from injury or disease : to make sound or whole heal a woundb : to make well again : to restore to health heal the sick.
From Wikipedia, the free encyclopedia. Wound healing is the process by which skin or other body tissue repairs itself after trauma. In undamaged skin, the epidermis (surface layer) and dermis (deeper layer) form a protective barrier against the external environment.