Immune nutrition refers to adding some special nutrients to the standard formula of nutrition in order to treat and regulate metabolism and immune function by its pharmacological effect. In recent years, immune nutrition, including glutamine, arginine, ω-3 PUFA, nucleotide etc, has been widely used in patients with gastrointestinal cancer. These nutrients show their different supporting functions through different mechanisms, and improve the clinical outcome of patients. Therefore, clinical nutrition has been expanded and upgraded from the traditional "nutrition" to "nutritional therapy".