Enteral nutritional support is an important and effective means of providing needed nutrients to patients. Four levels of support can be defined. Most patients are able to eat the diet prescribed for them (level 1), but some require forced nutritional support given by nasogastric (level 2) or nasoenteral (level 3) feeding tubes or by gastroenterostomy (level 4). Selection of the appropriate tube from among the many commercially available types with different features is important to minimize the risk of medical complications. How the tube is placed depends on whether the patient can or will cooperate. Proper positioning of the tube can be checked without an x-ray film by determining if four criteria have been met in a specified order.