LOTRONEX® in Severe Diarrhea-Predominant Irritable Bowel Syndrome (IBS-D)

This observational study will evaluate the effect of Lotronex® as used in the current clinical practice setting on symptom relief, specifically, improvement in bowel habits and IBS pain. Patients planning to initiate commercially available LOTRONEX® therapy will be consented for study participation. Patients will complete study questionnaires related to bowel symptoms, prior therapies, quality of life, productivity loss and treatment outcome. Investigators will also be asked to complete questionnaires related to the patient's disease characteristics, patient progress on study medication and treatment outcome.