It is used for microscopic colitis and works tremendously. It is a bile acid binding medicine, the amount taken can be played with until most symptoms are completely resolved. Budesonide kept me awake all the time so this has been perfect with no side effects for me.

From Mayo:
Anti-diarrheal medications such as loperamide (Imodium) or bismuth subsalicylate (Pepto-Bismol)
Steroids such as budesonide (Entocort EC)
Medications that block bile acids (which can contribute to diarrhea) such as cholestyramine/aspartame or cholestyramine (Prevalite), or colestipol (Colestid)
Anti-inflammatory medications such as mesalamine (Delzicol, Apriso, others) to help control colon inflammation
Medications that suppress the immune system to help reduce inflammation in the colon, such as mercaptopurine (Purinethol) and azathioprine (Azasan, Imuran)
TNF inhibitors, such as infliximab (Remicade) and adalimumab (Humira), which can reduce inflammation by neutralizing an immune system protein known as tumor necrosis factor (TNF)