This chapter contains sections titled: Definition of irritable bowel syndrome Prevalence and incidence of irritable bowel syndrome Irritable bowel syndrome and health services Pathogenesis of irritable bowel syndrome Making a diagnosis of irritable bowel syndrome Treatment of irritable bowel syndrome Prognosis of irritable bowel syndrome References Definition of irritable bowel syndrome Prevalence and incidence of irritable bowel syndrome Irritable bowel syndrome and health services Pathogenesis of irritable bowel syndrome Making a diagnosis of irritable bowel syndrome Treatment of irritable bowel syndrome Prognosis of irritable bowel syndrome References