Study of the Effectiveness of ETIASA® (Sustained Release 5-Aminosalicylate) in Maintenance Treatment of Ulcerative Colitis (UC)

Inclusion Criteria: * Male or Female patient ≥ 18 years old and ≤ 65 years old * Patient has provided written informed consent to participate in the study after the purpose and nature have been clearly explained to him/her; * Patient with documented diagnosis of mild-moderate Ulcerative Colitis (UC). The "documented diagnosis" should include a typical histology observed at least once in the course of the disease; * Have a documented history of UC that has been successfully maintained in complete steroid-free remission for at least 1 month prior to study entry; * The modified mayo score ≤ 2, without subscore \>1, which is supported by a rectum-sigmoidoscopy or a colonoscopy; * Regimen of maintenance of remission contains Etiasa® * Patient mentally and physically able to answer the questionnaire. Exclusion Criteria: * Have a history of allergy or hypersensitivity to salicylates, 5-aminosalicylates, or any component of Etiasa®; * Pregnant and breastfeeding women, approaching childbirth female or unwilling to take birth control measures during the study; * A topical 5-aminosalicylate agent is included in the regimen; * Patients with infectious colitis (positive for germs, ovum or parasites causing bowel disease); * Treated with the other study drug at enrollment, or within past 3 months of enrollment; * Serious underlying disease other than UC which in the opinion of the investigator may interfere with the patient's ability to participate fully in the study; * Crohn's disease; * Pancreatitis; * Known bleeding disorders; * Potentially unreliable patients, and those judged by the investigator to be unsuitable for the study.