Digestive System Home > Lactose Intolerance Information
A person who is unable to digest large amounts of lactose, the primary type of sugar found in milk, is said to have "lactose intolerance." Symptoms typically appear within 30 minutes to 2 hours of eating a product containing lactose, and can include abdominal cramping and diarrhea.
There are two general types of lactose intolerance -- primary and secondary -- and between 30 and 50 million Americans have this condition. In addition, certain ethnic and racial populations are more affected than others. It can be hard to diagnose, but treatment is fairly easily and usually just involves dietary modifications.
(For more information on this topic, click Lactose Intolerance. This article describes how this condition differs from a milk allergy, what causes it, how it is diagnosed, and more.)