This module covers Irritable Bowel Syndrome (IBS), including its definition, Rome IV diagnostic criteria, clinical subtypes, differential diagnosis, and multifactorial pathophysiology. It explores the role of the gut-brain axis, visceral hypersensitivity, dysbiosis, intestinal permeability, and immune activation in the development of IBS symptoms. The module provides detailed nutritional management strategies, including the three-phase Low-FODMAP diet, fiber modification, probiotics, and peppermint oil, along with identification of common dietary triggers. It also highlights the importance of regular meal patterns, stress management, psychological support, and multidisciplinary care for effective long-term symptom management.