Definition: It includes all conditions associated with disorders of digestion and failure of absorption of essential constituents of food characterized mainly by chronic diarrhea and malnutrition. Causes: Inadequate digestion: Partial or complete gastrectomy, obstructive jaundice, biliary cirrhosis, chronic pancreatitis, fibrocystic disease of pancreas pancreatic carcinoma, lactase and sucrase deficiency, Zollinger-Ellison syndrome. Disease of intestine: a) Inadequate absorptive surface: Resection of the gut, regional enteritis, bypass surgery. b) Inflammatory or infiltrative disease: Amyloidosis, Scleroderma, lamphoma, various skin disorders, tuberculous enterocolitis, cosinophilic enteritis, ulcerative colitis, Crohn's disease. c) Biochemical abnormalities: Non-tropical sprue, Hartnup disease, Coeliac disease. d) Lymphatic obstruction: Tabes mesenterica, Lymphoma, Whipple's disease, Talengiectasia. e)Altered bacterial flora: Blind loop syndrome, gastrocolic fistula, di...