3 bowel movements/week) Abnormal stool formations (lumpy/hard or loose/watery stool) Abnormal stool habitsQ (straining, urgency, or feeling of incomplete evacuation) Passage al mucusQ Bloating or feeling of abdominal distention The diagnosis of a functional bowel disorder always presumes the absence of a structural or biochemical explanation for the symptoms. Dagnostic criteria for Irritable Bowel Syndrome 1. Recurrent abdominal pain or discomfo at least 3 days per month in the last 3 months associated with two or more of the follow ing I. Improvement with defecation 2. Onset associated with a change in frequency of sioole 3. Onset associated with a change in form (appearance) of stoolQ. Criteria fulfilled for the last 3 months with symptom onset at least 6 months prior to diagnosis. Discomfo means an uncomfoable sensation not described as pain. In pathophvsiologv research and clinical trails, a pain/discomfo frequency of at least 2 days a week during screening evaluation is required for subject eligibility.">