This is a prospective, randomized control trial of adults meeting the Rome III criteria for FI and at least 1 episode of FI due to loose stool per week. After a 2 week screening period and randomization, during which the severity of symptoms will be assessed and eligibility determined, patients will be randomized to psyllium vs. low FODMAP diet for 4 weeks. A total of 20 patients will be recruited for each arm.