A colostomy is a surgical procedure to reroute the colon. It is most often is performed after removing part of the colon to treat colorectal cancer or other cancers of the abdomen or pelvis. However, it is also performed for conditions unrelated to cancer in which all or part of the intestines are removed, such as inflammatory bowel disease, diverticulitis or fecal incontinence. After the intestines are removed, stool cannot leave the body normally through the rectum and anus. An incision in the abdomen is used to bring the colon to the body surface, which creates a new opening known as a stoma. Wastes exit the body through the stoma and are captured in a bag attached to the patient.

Colostomies are created during surgery in a hospital setting. Patients are placed under general anesthesia, meaning they are not awake during the procedure. There are a few potential risks associated with colostomies, including narrowing or obstruction of the stoma, potential for hernia (protrusion of an organ or other bodily structure through the wall that normally contains it) at the incision site, and skin irritation.

In many cases, colostomies are a temporary procedure performed to allow portions of the body to heal after surgery. In other cases, colostomies are permanent, presenting emotional and lifestyle challenges to the patient.