The recovery time of lactose intolerance in infants varies from person to person and is related to the specific cause, severity and individual factors of the child, and should be analyzed on a case-by-case basis. If lactose intolerance in infants is caused by congenital lactase deficiency, lactase replacement therapy must be given for life, and recovery is usually impossible. It is often manifested as diarrhea, vomiting, increased gas accumulation in the stomach and intestines, and crying after eating lactose-containing dairy products. In milder cases, the symptoms usually return to normal in 5-7 days. For those with more severe symptoms of lactose intolerance, the degree of mucosal villi damage is more severe and the exact recovery time varies from person to person. During the period of lactose intolerance in infants, parents are advised to add lactase or adjust dairy products to their babies. During the acute period, anti-diarrheal formula with de-lactose can be fed temporarily, and then changed to formula after normalization.