Navigating the Four Types of Irritable Bowel Syndrome: A Guide to Personalized Management

Understanding the differences between IBS-C, IBS-D, IBS-M, and IBS-U is crucial for effective treatment. Learn about the symptoms and triggers for each type.

By: AXL Media

Published: Feb 26, 2026, 6:35 AM EST

Source: Health

The Bristol Stool Scale: The Diagnostic Foundation

To determine the subtype of IBS, gastroenterologists rely on the Bristol Stool Scale, a diagnostic tool that classifies human feces into seven categories. For a diagnosis of IBS, a person must have recurrent abdominal pain related to bowel movements or changes in stool frequency and appearance. The subtype is then defined by the consistency of the stool on days when bowel movements are abnormal. This objective measurement helps move beyond subjective patient descriptions to a clinical framework for treatment.

The Four Subtypes of IBS

IBS-C (Predominant Constipation): Characterized by more than 25% of bowel movements being hard or lumpy (Bristol types 1 and 2). Patients often experience straining and a sensation of incomplete evacuation.

IBS-D (Predominant Diarrhea): Characterized by more than 25% of bowel movements being loose or watery (Bristol types 6 and 7). This type is often associated with urgency and post-meal cramping.

IBS-M (Mixed Bowel Habits): Patients experience both constipation and diarrhea, with more than 25% of movements being hard and more than 25% being loose. This fluctuating pattern can be particularly challenging to manage.