Rome Criteria for irritable bowel syndrome, fifth revision: Key updates. A review

Abstract

The Rome V Criteria, published in 2026, updates the scientific and clinical understanding of irritable bowel syndrome (IBS). It redefines IBS from a “functional disorder” to a “gut-brain interaction disorder,” emphasizing biological underpinnings. Recognized pathophysiological mechanisms include impaired motility, alterations in the microbiota and its metabolites, immune dysregulation, serotonin modulation, increased intestinal permeability, visceral hypersensitivity, and bile acid malabsorption. The updated criteria define IBS as recurrent abdominal pain and/or discomfort associated with changes in bowel habits, such as constipation, diarrhea, or a mixed pattern, with symptoms present for at least six months prior to diagnosis and persisting during the preceding three months. Notable updates include the reintroduction of “abdominal discomfort,” a reduced pain frequency threshold of at least three days per week, clarification that pain or discomfort should not be constant, and an auxiliary criterion specifying that pain or discomfort should not be exclusively related to menstruation. IBS is now classified into four primary subtypes based on predominant stool patterns, as determined by the Bristol Stool Form Scale: IBS with constipation, IBS with diarrhea, IBS with mixed bowel habits, and IBS with unclassified bowel habits. Diagnosis is based on typical symptoms in the absence of alarm features, and IBS is no longer considered a diagnosis of exclusion. The revised diagnostic algorithm involves sequential clinical assessment, targeted use of a limited set of laboratory and instrumental tests, and explicit criteria for further evaluation. The Rome V Criteria also recommend a stepwise approach to IBS therapy, including lifestyle and dietary modifications, pharmacological management of predominant symptoms, and behavioral interventions targeting brain-gut axis interactions.