Clinical Research Directory

Inclusion Criteria: 1\. Subjects aged 18 and older meeting the Rome IV criteria for IBS-C\*: • Recurrent abdominal pain, on average, at least 1 day/week in the last 3 months, associated with two or more of the following: 1. related to defecation 2. associated with a change in the frequency of stool (reduction of stools) 3. associated with a change in the form of stool (hard or lumpy stools) AND \>25% hard stools and \<25% loose stools \* Criteria fulfilled for the last 3 months Exclusion Criteria: * any other IBS subtype other than IBS-C * \>3 spontaneous bowel movements during the last 7 days of run-in * Have cognitive dysfunction or unable to understand or provide written informed consent * Pregnancy (evaluated by self-report) * Comorbid medical problems that may affect gastrointestinal transit or motility: * Inflammatory bowel disease * Extra-intestinal disease known to affect the gastrointestinal system (i.e., scleroderma, unstable thyroid disease, etc.) * Severe renal or hepatic disease * Previous abdominal surgery other than appendectomy, cholecystectomy, and gynecologic/urologic surgery if performed more than six months prior to enrollment * Previous treatment with the low FODMAP diet under a dietician guidance * Concurrent medications not permitted including probiotics, antibiotics, prescription or over-the-counter medication for IBS, and narcotics * New antidepressant use (less than 3 months on stable dose) * Active participation in another form of dietary therapy