This is a prospective clinical intervention trial where patients with moderately active ulcerative colitis are randomized to either normal healthy diet or a diet with elimination of emulsifying agents within the E 400-group with special respect to carragenan, CMC and polysorbates. At study start and end after one month their diet, clinical characteristics and microbiota will be analysed. The hypotheses are that their disease activity measured with calprotectin and their microbiota will improve after intervention.