The purpose of this study is to assess the measurable changes in health, function, or quality of life (clinical outcomes) after receiving guselkumab in real-world clinical practice amongst Chinese participants with ulcerative colitis (UC; a long-term disease of the large intestine in which the lining of the colon \[part of large intestine\] becomes inflamed and develops tiny open ulcers), who have not received biologic therapy (a medicine made from living organisms or their components) previously.