The goals of nutritional support are to maintain or replenish lean body mass, support host defense mechanisms, avoid specific nutritional deficiencies, and generally improve clinical outcomes in malnourished patients or those at risk of malnutrition. Is to Nutritional support can be initiated by enteral or parenteral routes. Each has advantages and disadvantages. Which route of administration is chosen depends largely on the clinical condition of the patient. The enteral route is generally preferred as it is more physiological. In certain cases where the enteral route is impossible or dangerous, parenteral nutrition can be used as a life-saving alternative. A concise and comprehensive description of the pros and cons of nutritional support. Nutritional support is intended to maintain or replace lean body mass, support host defenses, prevent specific nutritional deficiencies, and generally improve clinical outcomes in patients who are malnourished or at risk of developing malnutrition. The decision to introduce nutritional support prompts discussion about how best to achieve these goals. There are two basic means of providing nutritional support. H. Via enteral and parenteral routes. Each has specific indications, strengths and weaknesses, and can be further subdivided based on degree of invasiveness. We propose an approach for determining the optimal modality for providing nutritional support. In principle, if the bowel is functioning, use it; if not, parenteral nutrition may be a life-saving alternative. Enteral nutrition is clearly preferred. The physiological function of the gastrointestinal tract is to provide an entry point for nutrients, facilitate digestion, absorption and metabolism, and act as a barrier to potentially harmful substances. There is evidence from animal and clinical studies that bypassing the luminal route, despite adequate parenteral nutritional support, adversely affects the intestinal mucosa. Insufficient enteral nutrition in well-fed rats and parental rabbits reduced the weight, thickness, protein and DNA content of the mucosal membrane, especially in the proximal gut. Rats given parenteral nutrition enterally had improved survival after induction of experimental septic peritonitis compared with their peers given the same solution intravenously. Finally, enteral nutrition is approximately 4-10 times cheaper than parenteral nutrition, even with invasive placement of a gastric or jejunal tube. To date, there are specialized drugs for use in preterm infants (rich in essential amino acids), liver disease (low aromatic and high branched-chain amino acids), lung disease (low carbohydrate-to-fat ratio), and metabolic disease. Enteral nutrition products are being developed. A great advantage of parenteral nutrition is that it provides sufficient nutrients in case of gastrointestinal disturbances. Central venous catheters are also useful in the face of fluid restriction, as they can increase caloric density beyond that permitted by the enteral route. Common indications for parenteral nutrition are: Unable, unwilling, or should not eat enterally or orally, or not eating enough or feeding adequately by tube this is a patient. Once the decision is made to initiate PN in a patient, it is important to determine whether the patient requires central or peripheral PN. A well-nourished patient, who needs her PN for a short period of time, has average low energy, protein, and electrolyte requirements, and has her PN through a peripheral venous catheter called a peripheral PN (PPN).