['irritable bowel syndrome']
['fecal microbiota transplantation capsules', 'placebo capsules']

        Inclusion Criteria:

          -  age 19-65 years

          -  established diagnosis of IBS-D as determined by Rome III Criteria

          -  moderate-severe disease activity (as determined by an IBS-Symptom Severity Score ≥175)

          -  persistent symptoms despite conventional therapy

          -  normal colonoscopy with biopsies in the past for work-up of IBS symptoms

          -  negative work-up for celiac disease either by duodenal biopsies or negative serologies

        Exclusion Criteria:

          -  pregnancy

          -  nursing

          -  cognitive impairment or severe neuropsychiatric comorbidities who are incapable of
             providing their own informed consent

          -  severely immunocompromised or immunosuppressed patients (e.g., organ transplant
             recipients, severe neutropenia with an absolute neutrophil count of <500cells/mL,
             current treatment or treatment within 3 months with anti-neoplastic agents and
             HIV-positive patients with CD4 counts <200cells/mm^3)

          -  treated with any antibiotics in the 3 months prior to FMT

          -  GI symptoms can be explained by the presence of an underlying organic disease
             including, underlying inflammatory bowel disease, infectious enteritis, previously
             established and untreated small intestinal bacterial overgrowth or known motility
             disorder

          -  previous FMT

          -  severe (anaphylactic) food allergy

          -  unable to comply with protocol requirements

          -  American Society of Anesthesiologists (ASA) Physical Status classification IV and V

          -  acute illness or fever on the day of planned FMT will be excluded (not randomized)
             with the option of including that subject at a future date

          -  new antidepressant started or dose of antidepressant change <3 months prior to
             enrollment

          -  elevated ESR or CRP within the past 3 months

          -  baseline laboratory abnormalities on CBC, chemistry or liver tests

          -  pain score >75 on IBS-SSS
      