The gastrointestinal tract extends from the mouth to the anus. The diseases and disorders which affect the gastrointestinal tract are termed as gastrointestinal diseases. These can be classified into two categories, functional and structural. The diseases wherein the gastrointestinal tract appears to be normal but does not function properly are termed as functional gastrointestinal diseases. Structural gastrointestinal diseases are the disorders of the gastrointestinal tract in which the bowel does not function properly and appears to be abnormal upon examination. A few disorders of the gastrointestinal tract are constipation, irritable bowel syndrome, hemorrhoids, anal fissures and anal fistula. This book discusses the fundamentals as well as modern approaches to the research on gastrointestinal disorders. Also included herein is a detailed explanation of the clinical management of these disorders. This book includes contributions of experts and scientists which will provide innovative insights into this field.