Inability to absorb macro or micro nutrients. Etiologies include: - Mucosal abnormalities: Celiac disease, Whipple disease, tropical sprue. - Bile salt deficiency: Ileal disease in Crohn disease or small bowel resection, bacterial overgrowth. - Other: Pancreatic insufficiency, short bowel syndrome. Patient presents with pale, foul smelling bulky stools (steatorrhea or fat maldigestion) associated with abdominal pain, flatus, bloating and fatigue. Diagnosis: Multiple lab test based on clinical suspicions. Biopsy is definitive. Treatment: Etiology dependant. In severe cases, patient may require TPN, immunosuppressant and anti-inflammatory medications.