Effects of Lubiprostone on Small Bowel and Colonic Bacteria: A Correlation Study With Segmental and Whole Gut Transit

Inclusion Criteria: Functional constipation by Rome III criteria Exclusion Criteria: 1. History of esophageal or gastric surgery (including vagotomy, antireflux, and obesity surgery) 2. History of small bowel or colon resection (excluding appendectomy and cholecystectomy) 3. History of gastric outlet, small bowel, or colon obstruction 4. History of surgery for small bowel adhesion lysis 5. History of surgery for gastroparesis 6. Diagnosis of diabetes requiring daily medications 7. Diagnosis of connective tissue d/o (including scleroderma, lupus, mixed connective tissue disorder) 8. Diagnosis of neuromuscular disorder (including multiple sclerosis, Parkinson, muscular dystrophy, dysautonomia, dystonia) 9. Disorders of small bowel pseudo-obstruction or dumping syndrome 10. Untreated or poorly controlled hypothyroidism 11. Taking an opiate medication daily 12. Taking a medication daily that can cause constipation (calcium channel blocker, anticholinergic, iron supplements, etc.) 13. Active cancer being treated 14. History of significant liver, kidney, cardiac disease that may interfere with study compliance 15. Known allergy or side effects to lubiprostone 16. Non-ambulatory patients: bed-ridden, nursing home resident, etc.