Inclusion Criteria:  Healthy volunteers Symptomatic IBD patients: Moderate to severe IBD in remission with persistent symptoms as reported by symptom index and short health scale. Asymptomatic IBD patients: moderate to severe IBD in remission without symptoms  Exclusion Criteria:  Healthy volunteers:  gastrointestinal disease, functional gastrointestinal symptoms, psychiatric disease anal or pelvic surgery, inclusive interventions during delivery diabetes, cardiovascular, renal, or hepatic disease, concurrent or recent treatment with drugs affecting intestinal function or mood (antidepressants), nutritional supplements or herb products affecting intestinal function (probiotics), abuse of alcohol or drugs, and a recent (< 2 weeks) history of systemic steroid therapy.  IBD patients  active disease anal or pelvic surgery, inclusive interventions during delivery diabetes, cardiovascular, renal, or hepatic disease, concurrent or recent treatment with drugs affecting intestinal function or mood (antidepressants), nutritional supplements or herb products affecting intestinal function (probiotics), abuse of alcohol or drugs, and a recent (< 2 weeks) history of systemic steroid therapy. Patients taking antidiarrhoeal or laxatives can be included after a 48 h washout period.