Nasogastric suction is the process of removing solids, liquids, or gasses from the stomach or small intestine by inserting a tube through the nose and suctioning the material through the tube. This procedure may be done in the following situations:

• To relieve pressure on the stomach or small intestine when intestinal obstruction is suspected.
• Before operations on the stomach or intestines.
• To obtain a sample of the stomach contents for analysis.
• To remove toxic substances.
• To flush the stomach during gastrointestinal bleeding or poisonings.

For this procedure, the patient sits upright while a lubricated tube is slipped through the nose and down the throat. The patient may be asked to sip water at a certain point in the procedure to help the tube slide in more easily. If the tube is to be placed into the small intestine, the doctor may use an endoscope (a thin, flexible instrument containing a camera and a light) to help see where the tube is going. Once the tube is in place, material can be removed from the stomach or intestines with gentle suction.

Different types of nasogastric tubes are used for different purposes. Tubes used for stomach flushing are called orogastric tubes and are the largest in diameter. Tubes that are threaded through the lower opening of the stomach (pylorus) and into the small intestine are stiffer and have a balloon tip.

Most patients tolerate nasogastric suctioning well. After the tube is removed, the patient's throat may feel irritated, but no special care is needed. The most serious risk from this procedure is that the patient will inhale some of the stomach contents into the lungs (aspiration). This may lead to bronchial infections and aspiration pneumonia. There is also the chance that the tube will be misplaced in the windpipe (trachea), causing violent coughing. Irritation to the throat and esophagus can cause bleeding.