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 how effective upadacitinib is in treating UC.

Upadacitinib (RINVOQ) is an approved drug for treating UC. Approximately 400 adult participants who are prescribed Upadacitinib by their physician in accordance with local label will be enrolled in Germany, Austria and Switzerland.

Upadacitinib will be administered in accordance with the terms of the local marketing authorization, and treatment of participants will be determined solely by the investigator. Participants in the study will be followed for up to 2 years.

There will be no additional burden for participants in this trial compared to their standard of care. Participants will attend regular visits during the study at a hospital or clinic and only data which are routinely collected during a regular visit will be utilized for this study.

Inclusion Criteria:

• Participants with an endoscopically confirmed diagnosis of active moderate to severe Ulcerative colitis (UC).
• Participants initiating Upadacitinib (UPA) at the investigator's discretion as part of their routine clinical care; the decision to administer UPA must be made prior to and independent of documentation for the study and according to the approved local label.
• Participants able to understand and communicate with the investigator and comply with the requirements of the study.
• Participants willing to continue with study documentation after cessation of UPA.

Exclusion Criteria:

• Participants with any contraindication to Upadacitinib (UPA).
• Participants previously exposed to a Janus kinase (JAK) inhibitor.

Adult participants with Ulcerative colitis (UC)