pump (one's) stomach
To use a mechanical pump to withdraw the contents of one's stomach, especially to remove toxic or poisonous substances. He got so drunk on his 21st birthday that we had to take him to the hospital so they could pump his stomach. The child was rushed to the emergency room to have her stomach pumped after swallowing a laundry detergent capsule.
pump somebody’s ˈstomach
remove the contents of somebody’s stomach using a pump, because they have swallowed something harmful: She had to go to the hospital and have her stomach pumped. ▶ ˈstomach pump noun