Final answer:
Gastric lavage is the medical procedure for washing out the stomach with a saline solution or sterile water, typically used in cases of toxic ingestion or overdose.
Step-by-step explanation:
The process of rinsing or washing out the stomach with a saline solution or sterile water is called gastric lavage. This medical procedure is often used in cases where a patient has ingested a toxic substance or overdosed on medication. It involves inserting a tube into the stomach through the mouth or nose to administer the saline solution or sterile water, which is then removed along with the contents of the stomach to cleanse it.