Investigation of the safety of Indigo naturalis for the patients with ulcerative colitis

INTERVENTION: Oral administration of Indigo naturalis 2g/day, 4 weeks CONDITION: ulcerative colitis PRIMARY OUTCOME: The existence of adverse effect SECONDARY OUTCOME: Clinical improvement rate; Improvement of the endoscopic findings INCLUSION CRITERIA: 1)Patients with ulcerative colitis 2)Patients older than 20 years old 3)Patients with moderate to severe activity 4)Patients resistant to the existing therapy with 5‐aminosalicylate, corticosteroids, or other drugs for ulcerative colitis 5)Patients with no change of drugs for at least 2 weeks before the enter to this study 6)Patients had not taken Indigo naturalis for 1 month before enrolling to this study