A colostomy is a surgical procedure that involves creating an opening (stoma) in the abdominal wall to divert the colon's contents outside the body. This is typically done when part of the colon needs to be removed or bypassed due to conditions like cancer, injury, or inflammatory bowel disease. The waste is collected in an external pouch attached to the stoma. Colostomies can be temporary or permanent, depending on the underlying medical condition.