Lactose intolerance.

Lactose intolerance affects more than 50 million Americans. It is one of the most common gastrointestinal disorders seen by primary care physicians. When this disorder is properly diagnosed, the patient is easily treated with education and dietary modifications. Lactose intolerance is commonly misdiagnosed because of its overlapping symptoms of diarrhea and abdominal bloating. This article reviews the etiology, diagnosis, and treatment of lactose intolerance.