Stomach pumping is a procedure for removing the contents of the stomach by inserting a tube and suctioning out the contents. Swallowing poison, consumption of too much alcohol, and accidental or intentional drug overdoses are the main conditions that require this procedure. Stomach pumping is also knows as gastric lavage or gastric irrigation.

When a patient has a toxic substance, such as poison or an overdose of drugs, that needs to be removed from the stomach, quick action minimizes the body's exposure to the toxic substance. In some instances medication is given to induce vomiting although certain types of poison should not be expelled by vomiting, which makes stomach pumping necessary for removal. In other cases, patients are unconscious and unable to take the medication to induce vomiting. Gastric lavage is the only means of removing the toxin. Patients who are unconscious need to be intubated before the procedure to prevent them from breathing the stomach fluids into their lungs.

To empty the contents of the stomach, the patient lays on their left side with their head lowered. A flexible, plastic tube is lubricated and then inserted through the nose or mouth into the stomach. Once it has been verified that the tube is correctly in place, the stomach contents are suctioned out through the tube. The stomach is then washed out with warm water or saline until the removed fluids are clear. Due to the risk of electrolyte imbalance, only saline is used in children.

After stomach pumping, patients are kept for a period of observation where they are monitored for a reaction to the poison, alcohol or drugs. The observation period varies depending on what was originally swallowed. In some instances, depending on what was consumed, activated charcoal is given to the patient to absorb any remnants of the toxins that may still be in the stomach. A cathartic medication may also be given to speed up emptying of the intestines.

Although ingestion of drugs or poison is the primary reason for stomach pumping, there are other circumstances in which it is used. Gastric lavage is sometimes performed to remove any contents from the stomach or digestive tract before surgery so that it is clear when surgery is performed. Stomach pumping is also used to determine levels of bleeding in the upper gastrointestinal tract, and in some instances, it is used as a cooling technique for hyperthermia.