The Collaborative International Dictionary
Chthonophagia
Chthonophagia \Chthon`o*pha"gi*a\, Chthonophagy \Chtho*noph"a*gy\, n. [NL. chthonophagia; Gr. ?, ?, earth + ? to eat.] A disease characterized by an irresistible desire to eat earth, observed in some parts of the southern United States, the West Indies, etc.
Wiktionary
chthonophagia
n. (context disease English) A disease characterized by the impulsive consumption of dirt, observed in some parts of the southern United States as well as the West Indies.