The objectives of this study are to investigate how oral 5-ASA drugs have been used in the condition without symptoms such as abdominal pain or diarrhea/bloody stool (remission stage), or in the transition from the condition with symptoms such as abdominal pain or diarrhea/bloody stool (active stage) to the remission stage in ulcerative colitis and to study how many patients will be able to maintain the remission stage during the observation period and how many times the patients will experience the active stage (relapse), as well as how symptoms will change during the observation period to discover better treatment plans.

Period: 2012-2014 Observation Time: 0, 26week, 52week

Matters investigated:

1. pUCDAI scores(Stool frequency, Bloody stool, Physician's global assessment)
2. Medication adherence (VAS scale)
3. Remission, Relapse
4. Age, gender, body height, body weight, date of diagnosis, extension of inflammation, classification by clinical course, smoking, alcohol, work, disease complication, duration of remission maintained to enrollment(remission patient)

Inclusion Criteria:

1. Outpatients
2. Adult patients who have been diagnosed with mild to moderate active ulcerative colitis or ulcerative colitis in the remission stage according to the diagnostic criteria for ulcerative colitis (draft revised on February 13, 2010)
3. Patients who have been treated with remission induction therapy or remission maintenance therapy with oral 5-ASA drugs (Pentasa® tablets 250 mg, Pentasa® tablets 500 mg, Asacol® tablets 400 mg and Salazopyrin® tablets 500 mg as well as drugs that have been proved equivalent to these drugs)
4. Patients who have received adequate information regarding this study and understood thoroughly, and then voluntarily submitted written consent forms upon participation in this study

Exclusion Criteria:

1. Patients with severe active ulcerative / fulminant ulcerative colitis according to the diagnostic criteria for ulcerative colitis (draft revised on February 13, 2012)
2. Patients who have received total / subtotal colectomy
3. Patients who have been complicated with malignant tumor
4. Patients who are pregnant or possibly pregnant
5. Other patients whom investigators and subinvestigators considered inappropriate to participate in this study

University, Main hospital, General Hospital, General Practitioner