Nutrition, as a definite environmental factor, has been implicated in the pathogenesis of inflammatory bowel disease (IBD). Although low-fiber, high-sugar, and high-animal fat diets have been proposed as a risk factor, the role of nutrition in IBD still needs more conclusive evidence. Nutritional deficiency is a common problem in IBD patients. The goals of nutritional intervention are the prevention and correction of malnutrition, the prevention of osteoporosis, and the promotion of optimal growth and development in childhood. Enteral nutrition is effective in induction and maintenance of the clinical remission in adults and promoting growth in children with Crohn's disease. The n-3 polyunsaturated fatty acids contained in fish oil may provide short-term benefit to patients with IBD.