<h4>Background/aims</h4>This study aims to assess the frequency of latent tuberculosis (TB) and the incidence of active TB infection in patients with inflammatory bowel disease (IBD) and Behçet's syndrome with gastrointestinal involvement who received either tumor necrosis factor-alpha (TNF-α) antagonist therapy or vedolizumab as a second-line biologic treatment following TNF-α antagonist therapy.<h4>Materials and methods</h4>A total of 349 patients were included in the study. This evidence concerns the gene TNF and inflammatory bowel disease.