Nail biting occurs when the child attempts to integrate two opposite motivations: the discharge of gross aggressions through oral-sadistic channels (hand and mouth being very closely linked in a biting-clawing relationship), and the strong need to deny those aggressions. Nail biting does not occur in infancy, appearing rather in the Oedipal phase, often as a successor to finger sucking. The nail biting is a healing device, aimed at coping with the problem of retaining rather than destroying the Oedipal rival on whom the child is still dependent. It bites at its own claws, releasing oral-sadistic impulses against its own dangerous weapons, and sparing the external object. Illustrative cases show the close connection with other sado-masochistic behavior and impulses.