What is the practice of eating oneself known as?

Self-cannibalism is the practice of eating oneself, also called autocannibalism, or autosarcophagy. A similar term which is applied differently is autophagy, which specifically denotes the normal process of self-degradation by cells. While almost an exclusive term for this process, autophagy nonetheless has occasionally made its way into more common usage.

A certain amount of self-cannibalism occurs unwillingly, as the body consumes dead cells from the tongue and cheeks. Ingesting one's own blood from an unintentional lesion such as a nose-bleed or an ulcer is clearly not intentional harvesting and consequently not considered cannibalistic. Ingesting one’s own blood on purpose from a deliberate wound however, is.

Fingernail-biting that develops into fingernail-eating is a form of pica. Other forms of pica include "Dermatophagia", and compulsion of eating one's own hair, which can form a hairball in the stomach. Left untreated, this can cause death due to excessive hair buildup. Self-cannibalism can also be a form of self harm and a symptom of mental illnesses such as personality disorders, psychosis, or drug addiction.