Breast milk can also cause lactose intolerance, primarily because it also contains lactose, which plays an important role in the nutrition of infants, promoting the development of the brain's nervous system and providing energy for the growth and development of the baby. However, conditions such as rotavirus gastroenteritis or chronic diarrhea can trigger a dysbiosis of the gut flora, leading to insufficient secretion of lactase in babies. Once lactose intolerance occurs and is not alleviated in time, it can prolong the course of the baby's diarrhea, cause digestive and nutritional absorption disorders, often resulting in watery stools increasing in frequency, and the baby may also experience nausea, vomiting, abdominal bloating, and other uncomfortable symptoms. Therefore, in such cases, it is necessary to temporarily stop breastfeeding, administer lactase or switch to lactose-free formula milk for management, and resume normal diet once the symptoms are relieved.