There are a significant number of gastrointestinal diseases which can be classified as functional diseases and structural diseases.  Functional gastrointestinal diseases consist of irritable bowel syndrome - IBS (IBS-Constipation predominant, IBS-Diarrhea predominant, and IBS mixed type), GERD/gastroenterological reflux disease or acid reflux, and functional dyspepsia.  Structural gastrointestinal diseases include: Hemorrhoids Anal fissures/fistula Colon polyps Diverticulitis Colitis