Inclusion Criteria:  Adults,18 years and older, either genders Subject previously diagnosed with left-sided colitis or pancolitis based on endoscopy and, if available, confirmed by histological examination of biopsy taken during endoscopy Subject in clinical and endoscopic remission. Remission will be documented by proctosigmoidoscopy. Subject who may receive maintenance therapy as per current medical practice, e.g. mesalazine, corticosteroids, azathioprine, anti-TNF Availability of stool specimen for basal time point Subject willing and able to sign, the approved Informed Consent Form for this project in accordance with international and national regulations Subject able to understand and follow study procedures  Exclusion Criteria:  Any subject that does not meet the inclusion criteria Subject with microscopic colitis Subject with Crohn's disease Subject with limited proctitis Subject with severe chronic disease affecting the possibility to comply with the study protocol (i.e. severe cardiovascular disease, renal or liver failure, neurologic disease, hematological disease and mental disorder) Subject who is regularly taking oral anticoagulants Subject who is currently pregnant or lactating Subject unable or unwilling to subscribe informed consent Subject unable or unwilling to perform required study procedures