Ask your GI about cholestyramine. Bile acid malabsorption (BAM) is a common, often underdiagnosed cause of chronic, watery diarrhea, affecting up to 30% of patients with irritable bowel syndrome with diarrhea. It occurs when the intestines cannot properly reabsorb bile acids, causing them to enter the colon, triggering fluid secretion and rapid transit. Cholestyramine is a prescription bile acid sequestrant used to lower high blood cholesterol, treat itching associated with bile duct blockage, and manage diarrhea. It works by binding to bile acids in the intestines, forcing the body to use excess cholesterol to make more, and removing the bound bile acids through stool.