The main causes of lactose intolerance: First, closely related to congenital factors, some people have congenital genetic defects that result in a reduction in the expression of the congenital lactase gene, and the activity of lactase decreases after birth, which is manifested as lactose intolerance. Second, acquired factors, such as a variety of infectious diseases, inflammatory bowel disease, radiotherapy, or surgery, medication damage to the small intestinal mucosa, making intestinal mucosal damage, resulting in the small intestinal mucosa digestion of lactose impaired ability, through the treatment of the primary symptoms can be relieved. Lactose intolerance is mainly manifested by gastrointestinal symptoms, such as abdominal distension, hyperactive bowel sounds, intestinal colic, diarrhea, nausea, vomiting. Treatment If the lactose intolerance is congenital, a lifelong abstinence from lactose is required. If lactose intolerance is secondary to some disease, treatment of the primary disease is most important. The goal of lactose intolerance treatment is to eliminate symptoms while avoiding nutritional deficiencies.