The guidelines provide a comprehensive overview of irritable bowel syndrome (IBS), aiming to guide the assessment and management of adult patients with IBS. IBS affects 5-11% of the population, with a peak prevalence in the third and fourth decades, and a female predominance. The guidelines emphasize the importance of classifying patients based on their predominant bowel habit and highlight that few investigations are typically needed unless diarrhea is prominent. Psychological features and somatic complaints are common, and addressing patients' concerns and explaining symptoms clearly improves outcomes. IBS is a heterogeneous condition with various treatments, each benefiting a small proportion of patients. Treatment for associated anxiety and depression often improves bowel and other symptoms. Randomized controlled trials show benefits from cognitive behavioral therapy, psychodynamic interpersonal therapy, hypnotherapy, antispasmodics, tricyclic antidepressants, ispaghula, 5-HT3 antagonists, 5-HT4 agonists, and selective serotonin reuptake inhibitors. The guidelines also discuss the need for better methods to identify which treatments will respond to specific patient subtypes. The development of the guidelines involved systematic literature searches and consensus-building among experts. The guidelines are intended for consultant gastroenterologists, trainees, and general practitioners with a special interest in gastroenterology. They are available on the British Society of Gastroenterology website and will be reviewed and revised every four years. The guidelines cover epidemiology, clinical features, mechanisms, and management of IBS, emphasizing the importance of recognizing alarm features and differentiating IBS from other conditions. They also discuss the role of genetics, gastrointestinal motility, visceral hypersensitivity, and stress response in the pathophysiology of IBS.The guidelines provide a comprehensive overview of irritable bowel syndrome (IBS), aiming to guide the assessment and management of adult patients with IBS. IBS affects 5-11% of the population, with a peak prevalence in the third and fourth decades, and a female predominance. The guidelines emphasize the importance of classifying patients based on their predominant bowel habit and highlight that few investigations are typically needed unless diarrhea is prominent. Psychological features and somatic complaints are common, and addressing patients' concerns and explaining symptoms clearly improves outcomes. IBS is a heterogeneous condition with various treatments, each benefiting a small proportion of patients. Treatment for associated anxiety and depression often improves bowel and other symptoms. Randomized controlled trials show benefits from cognitive behavioral therapy, psychodynamic interpersonal therapy, hypnotherapy, antispasmodics, tricyclic antidepressants, ispaghula, 5-HT3 antagonists, 5-HT4 agonists, and selective serotonin reuptake inhibitors. The guidelines also discuss the need for better methods to identify which treatments will respond to specific patient subtypes. The development of the guidelines involved systematic literature searches and consensus-building among experts. The guidelines are intended for consultant gastroenterologists, trainees, and general practitioners with a special interest in gastroenterology. They are available on the British Society of Gastroenterology website and will be reviewed and revised every four years. The guidelines cover epidemiology, clinical features, mechanisms, and management of IBS, emphasizing the importance of recognizing alarm features and differentiating IBS from other conditions. They also discuss the role of genetics, gastrointestinal motility, visceral hypersensitivity, and stress response in the pathophysiology of IBS.