Ulcerative colitis (UC) is a type of inflammatory bowel disease that causes inflammation and bleeding from the lining of the rectum and colon (large intestine). This study will assess the change in disease activity of risankizumab treatment in adult participants with moderate to severe UC in real-world clinical practice.

Risankizumab is an approved drug for treating participants with ulcerative colitis. Approximately 200 participants who are prescribed risankizumab by their physician in accordance with local label will be enrolled in approximately 30 sites across Japan.

Participants will receive risankizumab as prescribed by their physician according to their routine clinical practice and local label. Participants will be followed for up to 156 weeks.

There is expected to be no additional burden for participants in this trial. Participants will attend regular visits during the study at a hospital or clinic according to their routine clinical practice.

Inclusion Criteria:

• Participants with a diagnosis of moderate to severe Ulcerative Colitis (UC) commenced on Risankizumab (RZB) treatment prescribed as part of their routine clinical care at their clinical's discretion according to Japan approved label and treatment prescription recommendations/guidelines.
• The decision to prescribe RZB is made prior to and independently of study participation.
• Participants able to provide voluntary informed consent before any study-related activities or procedures (obtained/documented as per regulations). If the patient is under 18 years old, a patient's parent or legal guardian must be willing to give written informed consent.
• Participants who can understand and communicate with the investigator and comply with the requirements of the study, including collection of PRO data using a smart device (i.e., mobile phone) and continued PRO data collection after cessation of RZB.
• Participants without previous exposure to RZB.
• Participants who are not currently participating in interventional research (not including non-interventional studies, PMOS, or registry participation).

Exclusion Criteria:

See Inclusion Criteria

The study population will include adult participants with moderate to severe UC who are being treated with RZB according to the relevant approved license and who are eligible according to the study eligibility criteria.