What is the difference between an ileostomy and a colostomy?

When a portion: Of small intestine (ileum) is brought to skin level, it is called ileostomy. When a portion of large intestine (colon) is brought to skin level, it is called a colostomy.

See below: A colostomy has an open end of the colon coming out to the skin. An ileostomy has an open end of the small intestine.

Location, location: Colostomy is surgically created from the colon opening to the skin. Sometimes temporary, sometimes permanent, depends on the cause for it. Usually on the left side, opens into a bag. Ileostomy is surgically created form the small bowel to the skin. Can open into a bag, or have internal valve ("continent ileostomy").

Many: An ileostomy is made from the end of small bowel, tends to have a higher output and be more liquid and tends to be slightly more difficult to maintain. A colostomy is made from the colon (usually sigmoid) has output with a consistency of regular bowel movements. The are different situations (usually anatomical) for construction of one verses the other.