Protein-energy malnutrition and specific nutrient deficiencies are common in inflammatory bowel diseases (IBD), more particularly in Crohn's disease. In adults, the use of artificial nutrition is indicated in the event of malnutrition, short bowel syndrome, or IBD refractory to all other treatments. In children, enteral nutrition has a place as first-line treatment to avoid side effects of corticosteroids on growth. The use, as a therapeutic tool, of specific nutrients (n-3 fatty acids, glutamine, antioxydant vitamins and minerals, TGF-β, probiotics...) seems interesting at the pathophysiological level. Nevertheless, these nutrients are still under evaluation and there are not enough available studies to recommend them in clinical routine. A very promising solution is the use of probiotics for the treatment of refractory pouchitis.