Assessment of Whole Gut Transit Time Using the SmartPill Capsule

Inclusion Criteria: * Males and females between ages of 18-80 years of age with functional constipation that fulfills the Rome II definition of functional constipation * Bowel movement frequency of \< 3 times per week but at least once per two weeks. * Constipation symptoms for at least 1 year duration. * Constipation, not abdominal pain, as the primary symptom. * Ability to stop fiber, laxatives, prokinetic agents, and narcotic analgesic agents 3 days prior to the study and during the 5 day study period. * Ability to stop proton pump inhibitors 7 days prior to the study and H2RAs for 3 days prior to the study. Exclusion Criteria: * Previous history of bezoars. * Prior GI surgery except for cholecystectomy, appendectomy, or Nissen fundoplication * Any abdominal surgery within the past 3 months * Known or history of inflammatory bowel disease * History of diverticulitis, diverticular stricture, and other intestinal strictures * Tobacco use within eight hours prior to capsule ingestion and during the initial 8 hour recording on Day 0 or the Ingestion visit. * Alcohol use within eight hours prior to capsule ingestion and throughout the entire monitoring period (5 days). * BMI \> 38 * Allergies to components of the SmartBar (Appendix IX). * Females of childbearing age who are not practicing birth control and/or are pregnant or lactating. (A urine pregnancy test will be performed on female subjects prior to capsule ingestion). * Cardiovascular, endocrine, renal, or other chronic disease likely to affect motility. * Use of medical devices such as pacemakers, infusion pumps, or insulin pumps. * Any contraindication to use of Fleets Enema or balloon expulsion test. * Uncontrolled diabetes with a hemoglobin A1C greater than 10.