The irritable bowel syndrome is a common disorder of gastrointestinal motility. Abdominal pain, bloating, and inconsistent bowel habits are the hallmark symptoms of irritable bowel syndrome. Fever, weight loss, and gastrointestinal bleeding often indicate more serious pathologic gastrointestinal conditions, such as inflammatory bowel disease or infectious enteritis. Because irritable bowel syndrome is so prevalent in our society, the primary care physician should be able to readily recognize the clinical features of this disorder in order to spare patients expensive, unnecessary diagnostic and therapeutic interventions. In this review, the authors discuss the clinical and psychological features of irritable bowel syndrome and offer a useful approach to the diagnosis and treatment of this disorder.