 It is usually reserved for patients who have ingested toxic doses of medications not absorbed by activated charcoal (such as iron and lithium), potentially toxic ingestions of sustained-release or enteric-coated drugs, or in the situation of packaged drug ingestion (body packing/stuffing).Whole bowel irrigation is undertaken either by having the patient drink the solution or a nasogastric tube is inserted and the solution is delivered down the tube into the stomach.When administered to adolescents and adults as preparation for surgery, colonoscopy, or another procedure, the solution is usually taken orally, unless oral administration is contraindicated.