Irritable bowel syndrome (IBS) is a chronic disorder of unknown origin, which is a very common disease and a frequent complaint among patients consulting general practitioners or gastroenterologists. It is primary characterized by abdominal pain, alteration in bowel habit, abdominal discomfort that can significantly affect quality of life (QOL). Measurements of QOL in IBS patients are more complete than a symptomatic score for the evaluation of patient status, which would increase to use as the assessment of therapeutic effects.