Further maintenance of remission for a year after Qing-Dai withdrawalin ulcerative colitis treatment: randomized controlled trial

INTERVENTION: stop oral administration of Qing‐Dai continue oral administration of Qing‐Dai CONDITION: ulcerative colitis PRIMARY OUTCOME: remission rate after 52 weeks INCLUSION CRITERIA: 1) Patients who undergo the treatment of Qing‐Dai over a year 2) Patients whose disease activity is 1 or 0 by Mayo endoscopic score 3) Patients who received full‐explanation and completely understood the study. 4) Patients with no change in treatment within the past 2 weeks before the commencement of the study 5) Patients with no change in treatment of ulcerative colitis during their oral administration of Qing‐Dai 6) Patients who have voluntarily submitted written consent forms upon participation in this study