Nasogastric tube: A tube that is passed through the nose and down through the nasopharynx and esophagus into the stomach. Abbreviated NG tube. It is a flexible tube made of rubber or plastic, and it has bidirectional potential. It can be used to remove the contents of the stomach, including air, to decompress the stomach, or to remove small solid objects and fluid, such as poison, from the stomach. An NG tube can also be used to put substances into the stomach, and so it may be used to place nutrients directly into the stomach when a patient cannot take food or drink by mouth.