Folate (pteroylmonoglutamate) is absorbed throughout the small intestine, though mainly in the Jejunum, binding to specific receptor proteins. Diffuse inflammatory or degenerative diseases of the small intestine, such as Crohn's disease, coeliac disease, chronic enteritis or entero-enteric fistulae, may reduce the activity of pteroyl polyglutamase (PPGH), a specific hydrolase required for folate absorption, and thereby leading to folate deficiency.