Crohn's disease (CD) is an incurable chronic inflammatory disorder of the gastrointestinal tract. This study will assess how safe and effective upadacitinib is in treating moderately to severely active CD in real world. Speed of onset and durability of effectiveness will be assessed.

Upadacitinib is a drug approved for the treatment of CD. All study participants will receive upadacitinib as prescribed by their study doctor in accordance with approved local label. Approximately 1200 participants will be enrolled in approximately 230 sites across the world.

Participants will receive upadacitinib as prescribed by their physician according to their routine clinical practice and local label. Participants will be followed for up to 3 years.

There is expected to be no additional burden for participants in this trial. Study visits may be conducted on-site or virtually as per standard of care.

Inclusion Criteria:

• A diagnosis of moderate-to-severe crohn's disease (CD).
• Participants initiating upadacitinib at the clinician's discretion as part of their routine clinical care; the decision to administer upadacitinib must be made prior to and independent of recruitment into the study.
• Participants prescribed upadacitinib in accordance with the approved local label.
• Able to understand and communicate with the investigator and comply with the requirements of the study.
• Willing to continue with study documentation after cessation of upadacitinib.
• Willing and able to participate in the collection of PRO data via a cloud-based application on their personal or provided mobile phone or website app.

Exclusion Criteria:

• Any contraindication to upadacitinib.
• Previously exposure to upadacitinib in a clinical trial.
• Currently participating in interventional research (not including non-interventional study, post-marketing observational study (PMOS) , or registry participation).
• Initiation of upadacitinib prior to enrollment.

Adult participants with Crohn's disease (CD)