What is the difference between ileostomy and a colostomy?

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.
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").

Related Questions

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. Read more...
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. Read more...