Due to infective agents * HIV related<unk>  * Intestinal tuberculosis * Parasites e.g., diphyllobothrium (fish tape worm) (B12<unk> , giardiasis (Giardia lamblia), hookworm (Ancylostoma duodenale roundworm, and Necator americanus) * Traveler's diarrhea * Tropical sprue * Whipple's disease Due to structural defects * Blind loops * Fistulae, diverticula and strictures * Infiltrative conditions such as amyloidosis, lymphoma, eosinophilic gastroenteritis * Inflammatory bowel diseases, as in Crohn's disease * Radiation enteritis * Short bowel syndrome * Systemic sclerosis and collagen vascular diseases Due to surgical structural changes * Bariatric surgery (Weight loss surgery) * Gastrectomy; Vagotomy Due to mucosal abnormality * Coeliac disease * Cows' milk intolerance * Fructose<unk>  * Soya milk intolerance Due to enzyme deficiencies * Lactase deficiency inducing lactose intolerance (constitutional, secondary or rarely congenital) * Intestinal disaccharidase deficiency * Intestinal enteropeptidase deficiency * Sucrose intolerance Due to digestive failure * Bile acid/Bile salt<unk>  * Bacterial overgrowth * Obstructive jaundice * Primary bile acid diarrhea * Terminal ileal disease such as Crohn's disease * Pancreatic insufficiencies: * Carcinoma of pancreas * Chronic pancreatitis * Cystic fibrosis * Zollinger-Ellison syndrome Due to other systemic diseases affecting GI tract * Abetalipoproteinaemia * Addison's disease * Carcinoid syndrome * Coeliac disease * Common variable immunodeficiency (CVID) * Fiber Deficiency * Hypothyroidism and hyperthyroidism * Diabetes mellitus * Hyperparathyroidism and Hypoparathyroidism * Malnutrition Other Possible Causes * Chronic Proton Pump Inhibitor Use
Malabsorption
Lead poisoning
Bile acid malabsorption
Gastroenteritis
Fructose malabsorption
Fecal vomiting
Lactose intolerance
Glucose-galactose malabsorption