If a child has lactose intolerance, the main symptoms are related to the digestive system, such as frequent bloating. Children may experience bloating and restlessness at night, and even signs of intestinal colic. There are abnormal bowel movement frequencies, such as constipation for several days, as well as diarrhea with a noticeable increase in stool frequency and a looser stool consistency. Sometimes, there may be symptoms of bloody stools, which should alert caregivers to the possibility of lactose intolerance. Lactose intolerance is divided into primary and secondary forms. Primary lactose intolerance is more common in Chinese due to genetic factors. Secondary lactose intolerance is mainly due to other reasons that lead to a deficiency of intestinal lactase, with infections and acute gastroenteritis being common causes. For children with lactose intolerance, lactase can be added to breast milk or lactose-free formula can be used. It is also advised to regularly recheck urinary lactose levels. If levels return to normal, breastfeeding can continue. If abnormalities persist, gradually introduce solid foods, as a normal diet usually does not significantly affect the child.