Inclusion criteria:  A confirmed clinical diagnosis of IBD of any duration, age 18 years or older, with mild to moderate disease and on standard therapy. The diagnostic criteria for IBD include the presence of chronic diarrhea for more than four weeks, and evidence of active inflammation on endoscopy and chronic changes on biopsy. Patients with stable mild to moderate IBD will be eligible for the study. Stable IBD is defined as having stable symptoms over a period of several weeks, diagnostic evaluation has been completed and the patient has been on consistent medication. Mild to moderate IBD is indicated by a Partial Mayo score (Mayo Clinic Score/Disease Activity Index for Colitis) of between 1-6, and a total of Mayo score of 1-10. For patients with Crohn's disease, only those with Crohn's colitis will be included (patients with small bowel disease are eligible to enter the trial as long as they also have large bowel inflammation).  Exclusion criteria:  Pregnancy, breastfeeding, allergy to seafood or marine products Severe medical illness such as uncontrolled diabetes (HbA1C>10), significant or unstable cardiovascular or pulmonary disease, impaired renal function (Cr>2.0mg/dL), current or recent (<1 year) malignancy, or other significant medical illness that in the view of the investigators may impair participation in the study. Patients with severe IBD (defined by a Partial Mayo score of 7-9 and a total Mayo score of 11-12, with active symptoms) will not be eligible to participate in the study.