Dietary antigens may act as important stimuli of the mucosal immune system and have led to the study of nutritional therapy for IBD. Patients with active CD respond to bowel rest, along with total enteral nutrition or TPN. Bowel rest and TPN are as effective as corticosteroids at inducing remission for patients with active CD, although benefits are short-lived. Enteral nutrition is consistently less effective than conventional corticosteroids for treatment of active CD. Use of palatable, liquid polymeric diets in active CD is controversial, but these diets are of equal efficacy when compared with elemental diets. UC has not been treated effectively with either elemental diets or TPN. Fish oil contains n-3-PUFA, which inhibits production of proinflammatory cytokines and has some benefit in the treatment of CD. Topical applications of short-chain fatty acids have benefited diversion colitis and distal UC, whereas probiotics hold promise in the treatment of pouchitis.