I especially find this part interesting: "Secondary Lactose Intolerance (SLI) Lactase is made in a delicate and vulnerable part of the small intestine. If the intestine is damaged, so is the body's ability to manufacture lactase. This condition is called Secondary Lactose Intolerance to distinguish it from the natural gradual loss of lactase ability. The list of conditions that can bring on SLI is a long one. Many diseases can, from a simple gastrointestinal flu (very common in infants) to deadly illness like cancer. Operations to the small intestine, especially those that remove portions of it, are also a leading cause. But some drugs can produce it, and so can long-term trauma to the body as in alcoholism. Whether SLI is temporary or permanent depends on the cause. Often the condition goes away after the intestines have had time to heal. Infants may become temporarily intolerant several times in just a couple of years. On the other hand, if you are an adult who was beginning to lose your lactase-producing ability naturally, even a slight shock to the intestine may cause a permanent inability."------------------Missycat