Rational:Wilson disease (WD), also known as hepatolenticular degeneration, is an autosomal-recessive hereditary disease with abnormal copper metabolism. Crohn disease (CD) is a chronic inflammatory gastrointestinal disease, which belongs to inflammatory bowel disease, all segments of the gastrointestinal tract can be affected, especially the terminal ileum and colon, accompanied by extraintestinal manifestations and related immune disorders. WD complicated by ulcerative colitis has been reported before, but WD complicated by CD has not been reported so far.Patient concerns and diagnosis:We presented the first report of a young patient with WD complicated by CD, who was admitted to the hospital because of repeated low fever, elevated C-reactive protein for 3 years, and anal fistula for 6 months.Interventions and outcomes:In this complicated disease, Ustekinumab is safe and effective.Lessons:We conclude that copper metabolism and oxidative stress play important roles in WD and CD.