A morbid impulse to eat unnatural foodstuffs; such as, ice, dirt, paint (including flaking paint), clay, laundry startch, gravel, plaster, or hair.

This condition is known in medical fields as pica which comes from Latin meaning “magpie” because this bird eats just about anything or carries away odd objects.

Pica and unusual food cravings (citta) are common in pregnant women. Pica also occurs in some patients with iron or zinc deficiencies. In children this syndrome, classified with eating disorders, is a rare mental disorder with onset typically in the second year of life; it usually remits in childhood but may persist into adolescence.

An expanded page about Allotriophagy.
Details about pica.
It's Pica Again.