Inclusion Criteria:  Xeljanz (tofacitinib) usage for ulcerative colitis Diagnosis of ulcerative colitis (ICD-10: K51.0, K51.1, K51.2, K51.3, K51.5, K51.8, K51.9) between January 2010 and December 2021 (incident or prevalent).  Exclusion Criteria:  Age < 18 years at the start of tofacitinib use Use of tofacitinib before reimbursement (1.3.2019) < 8 weeks of treatment with tofacitinib at the start of data mining History of panproctocolectomy, IPAA or ileostomy.