Biomarkers that accurately reflect immune activity are lacking in the treatment of Crohn's disease. Prolactin has immunomodulatory functions, but its role in Crohn's disease is unclear. The study investigated changes in serum prolactin levels in 185 patients with Crohn's disease and 58 healthy controls. Prolactin levels were significantly higher in CD patients than in controls (p<0.001). Higher baseline prolactin levels correlated with greater reductions in CRP after treatment. The study population had no previous reproductive history. Elevated serum prolactin levels may serve as an additional biomarker reflecting immune dysregulation and disease activity, especially in the severe, perianal dominant type. Its role in the assessment of therapeutic efficacy requires further investigation.