The nutritional support of acutely ill patients is very important and early enteral nutrition is recommended. Feeding via the nasogastric route is used widely for its ease of access if the patient cannot maintain volitional food intake. If the position of the tip or side holes of the nasogastric tube (NGT) is above the gastroesophageal junction, there is the possibility of retention and solidification of the administered enteral feeding formula in the esophagus. Therefore, the tip of the NGT should be checked carefully; a chest radiograph to confirm its position can be considered, especially in patients with a higher risk of aspiration and gastroesophageal reflux. In addition, careful consideration of the risk factors that can trigger esophageal obstruction is required when feeding patients in the intensive care unit. This paper describes two unusual cases of esophageal obstruction caused by the solidification of residue of an enteral feeding formula.