Even with the development of new therapeutic agents, such as infliximab, enteral nutrition (EN) and parenteral nutrition (PN) therapies remain important for the treatment of Crohns disease because Crohns patients often require nutritional support. Furthermore, nutritional therapies can be used in the control of disease activity. Elemental diets, which are mainly used in EN therapy, consist of a refined amino acid mixture, glucose or maltodextrins and minimal essential fatty acids. EN therapy can reduce mucosal inflammation by the elimination of dietary antigens, which induce inflammation, and by reductions in fat, which activates inflammation. EN is applied not only as induction therapy, but also as maintenance therapy after remission (home EN). However, the unpalatability of elemental diets, difficulties related to self-intubation and the high cost of EN have limited its application as a primary therapy in western countries. PN is utilized as complete bowel rest supporting nutrition. However, since the therapeutic efficacies of EN and PN are similar, the indications for PN are limited and PN is mainly utilized in patients with bowel obstructions or severe fistulas. PN is also used as home therapy in the treatment of Crohns patients with short bowel syndrome. However, long-term PN sometimes causes life-threatening complications including catheter-induced sepsis, liver failure and lethal mineral deficiencies. We suggest that gastroenterologists should recognize the advantages and limitations of all therapies and choose carafully or combine various therapies in order to maintain the quality of life in individual patients even if in cases where remission can not be achieved.