Irritable bowel syndrome (IBS) is a common disorder characterized by abdominal pain or discomfort and altered bowel habit (chronic or recurrent diarrhea, constipation, or both) that occurs more frequently in women than in men. Severe IBS may be underrecognized and inadequately managed in clinical practice. Although no consensus definition for “severe IBS” exists, patients may be categorized as having severe illness if they show an insufficient response to conventional treatments or if their functionality or quality of life is impaired as a result of their IBS symptoms. Nurses can be an important resource in optimizing the evaluation and treatment of these patients. Nursing assessments that delineate predominant symptoms and the history and nature of prior interventions (e.g., lifestyle changes, over-the-counter or prescription medication trials, psychotherapy, alternative treatments) and subsequent responses are important when advising patients and participating in the management of their IBS. Likewise, the nurse's assessment should include a history of symptom severity and impact on daily functioning, as these elements are important to choosing therapy. The nurse–patient dialogue should also include a description of available treatment options and the benefits and risks associated with each. By maintaining such a dialogue, nurses can hasten IBS recognition, improve management, limit the negative consequences of this common disorder, and improve overall treatment outcomes in this population.