The diagnosis of functional gastrointestinal (GI) disorders has been hampered by the lack of positive objective criteria. This chapter describes a rational, integrated approach to the medical treatment of functional GI disorders from the perspective of the clinical gastroenterologist. By current definitions the functional GI disorders are a variable combination of chronic or recurrent GI symptoms not explained by structural or biochemical abnormalities. Several clinical entities may be subsumed under broad rubric, including noncardiac chest pain, non-ulcer dyspepsia, irritable bowel syndrome, chronic abdominal pain, pelvic-floor dysfunction, and biliary dyskinesia. Debate continues as to whether functional GI disorders are due primarily to disturbances in normal GI motility and physiology that interact with psychosocial factors that secondarily affect the GI tract. A host of psychological abnormalities have been detected in subsets of patients with functional GI disorders, including depression, anxiety, somatization, phobia, and panic disorder.