Ostomy is related to the medical procedure known as a stoma. This is a surgical opening in the body for various purposes. The most common type is a colostomy. This involves cutting or removing a portion of the abdominal wall leaving a hole in it. This hole is then used to access the colon and allow feces to be removed directly. The feces no longer leaves the body through the usual route but instead comes out through the stoma and into a collecting bag that will be attached to the patient for this purpose.

Another type of ostomy is an ileostomy. This is similar to the colostomy but intead of accessing the colon it is used to access the small intestine. A tube can then come from the intestine to the skin to allow for intestinal waste to be evacuated.

Reasons for these procedures include Crohn's disease, ulcerative colitis and Familial adenomatous polyposis.