No one can deny that biological therapy using TNF-a inhibitors has revolutionized not only the management and outcomes of inflammatory bowel disease, but many dermatological and rheumatological diseases as well. Unfortunately, this biological therapy is also associated with an increased risk of opportunistic infections, including active tuberculosis. A risk that cannot be ignored, especially in countries with a high incidence of tuberculosis like Morocco. Here, two cases are presented of patients with crohn's disease on biological therapy who developed a very aggressive form of disseminated tuberculosis. It is therefore imperative to screen for latent tuberculosis in patients who are candidates for biotherapy, and also to ensure close monitoring throughout the treatment period.