Gastric lavage is the medical procedure of washing out the stomach — passing a wide-bore tube through the mouth into the stomach and flushing with fluid to remove its contents. It was once routine emergency treatment for swallowed poisons and drug overdoses, but its use has narrowed sharply: evidence showed limited benefit, and risks include pushing toxins further into the gut, damaging the oesophagus, and causing aspiration pneumonia. Modern toxicology favours activated charcoal, antidotes, and supportive care, reserving lavage for rare cases of life-threatening ingestion within the first hour where charcoal cannot be used. The term also covers diagnostic lavage to sample stomach contents for analysis.