Irritable Bowel Syndrome (IBS) is a chronic functional gastrointestinal disorder characterized by recurrent abdominal pain associated with changes in bowel habits, without identifiable structural or biochemical abnormalities. IBS is classified into subtypes based on stool pattern: IBS with predominant diarrhea (IBS-D), constipation (IBS-C), mixed bowel habits (IBS-M), or unclassified IBS.

The pathophysiology of IBS is multifactorial and includes altered gut motility, visceral hypersensitivity, dysregulation of the gut–brain axis, psychosocial stressors, dietary triggers, and changes in the gut microbiome. Hormonal influences and prior gastrointestinal infections may also contribute. Although IBS does not cause permanent intestinal damage, symptoms can be persistent and significantly impact daily functioning and quality of life.

Common symptoms include crampy abdominal pain, bloating, excessive gas, urgency, constipation, diarrhea, or alternating bowel patterns. Symptoms often fluctuate and may worsen during periods of stress, after certain foods, or with disrupted sleep. Alarm features such as unintentional weight loss, anemia, or bleeding require further evaluation to exclude organic disease.

Diagnosis is based on clinical criteria supported by targeted investigations to rule out other conditions. Management is individualized and focuses on symptom control and trigger identification. Core strategies include dietary modification (such as structured elimination approaches), gut-focused lifestyle interventions, stress management, and patient education. Long-term care emphasizes reassurance, regular follow-up, and quality-of-life improvement through a holistic, multidisciplinary approach.