An ileostomy is a surgical procedure that is used when the lower part of the digestive system (the colon) is diseased or damaged and is not able to function normally. An ileostomy allows body waste to leave the body through a surgical opening.

In this procedure, a hole is made in the abdomen. Then a portion of the small intestine (the ileum) is brought to an opening in the skin (a stoma). Waste leaves the body through the stoma instead of the anus. The waste is collected in a pouch attached to the stoma with adhesive.

Ileostomies may be done if all of the colon is removed or diseased, such as from ulcerative colitis or Crohn's disease.