The primary function of the gastrointestinal system is to assist the intake and further processing of food and liquids. Besides that, it forms an anatomical barrier between the external environment and internal milieu. It is also highly important for its paracrine and endocrine function. Inflammatory bowel diseases, which frequently cause a gastro- intestinal failure, form a specific group. Most frequently it is the ulcerative colitis and Crohn’s disease. Impaired integrity of the gastrointestinal mucosa and failure of protective mechanisms lead to the increased permeability of the intestinal wall for antigens derived from food, saprophytic bacteria and pathogenic microorganisms. When the gastrointestinal failure is threatening, factors determining its residual function become more important. As decisive reveals the severity and location of the primary disease. Previous surgeries and adaptation of the residual part of the gastrointestinal system are important, as well as the possibility of peroral or enteral nutrient intake. Depending on the presence of risk factors and the degree of residual gut function, some complications can be expected: dehydration, mineral disorders, symptoms of protein and energy depletion, infection, and multiple organ dysfunction syndrome. It is highly important to decide whether the gastrointestinal system will be included into or excluded from the process of realimentation. Critically ill patients with inflammatory bowel diseases should be treated at an intensive care unit.

        Key words: inflammatory bowel diseases, gastrointestinal failure, metabolic disorders.