The enteral nutrition involves food intake or commercial nutritional solutions intake via feeding tubes into stomach, duodenum or jejunum. Today, there is an emphasis on the importance of enteral nutrition for the patient's optimal recovery after surgery. The old dogma says that patients should not receive anything by mouth after gastrointestinal surgery because it improves anastomosis healing. It also says that gastrointestinal tract does not return its function until the bowel sounds are positive. Unlike this, it has been proven that the use of enteral nutrition in the first 24 hours after surgery is safe and even has positive effects on anastomosis healing, and gastrointestinal tract function returns soon after surgery, even in the absence of peristalsis. Enteral nutrition prevents bacteria translocation as well. In the beginning of the thesis the term of enteral nutrition is introduced, its beginnings, the ways of administration and types of formulas. Next, the importance of the enteral route of administration and its advantages comparing to parenteral nutrition are explained. Also, indications, contraindications, as well as complications of the use of enteral nutrition are discussed. In the next two chapters the importance of nutritional assessment of surgical patients is suggested. The association of malnutrition and adverse postoperative outcomes is explained and the methods of nutritional risk assessment are mentioned. Then, the body response to surgical trauma which may adversely affect the outcome is dealt with. All those negative aspects may be corrected or mitigated with the use of enteral nutrition. The development of enteral nutrition has been improved and nowadays there is the use of immunoenhanced formulas which additionally modulate immune and metabolic stress response related to surgical trauma. Therefore, we offer the review of the main immunonutrients activity and its use in clinical practice. In the end of the thesis current guidelines on enteral nutrition and information from the literature which refer to its use in the gastrointestinal surgery are summarized: esophagus resections, gastrectomies, pancreas surgery, lower gastrointestinal tract surgery and the use after liver transplantation. In the conclusion, the safety of the use of postoperative enteral nutrition is indisputable. Moreover, it has shown the benefits compared to parenteral nutrition or conditions without nutritional support. It decreases the postoperative complications rate, primarily the infectious ones, it reduces the length of hospital stay and, ultimately, it reduces the treatment costs.