Whether to switch formula for infants with lactose intolerance should be assessed based on the specific condition of the baby. If the baby's symptoms of lactose intolerance are mild, they can be managed by adding lactase and probiotics. However, if the baby has had diarrhea for a long time, frequent bowel movements, and also shows signs of reduced urine output, decreased skin turgor, and lethargy, it indicates a more severe dysfunction in the digestive system. In this case, it is necessary to switch to lactose-free formula to prevent exacerbation of gastrointestinal dysfunction. It is also important to pay attention to the baby's food hygiene and hand hygiene in daily life, especially during the peak season of diarrhea in autumn. It is advisable to get vaccinated in advance to prevent the transmission of other digestive system diseases.