If a child has lactose intolerance, they usually do not experience constipation. Lactose intolerance typically refers to a deficiency of lactase in the small intestine mucosa of newborns, which leads to the impaired digestion and absorption of lactose in milk and causes related symptoms. The clinical symptoms mainly include diarrhea, bloating, and abdominal pain, often accompanied by increased bowel sounds and spasmodic diarrhea. In severe cases, dehydration, vomiting, or acidosis may occur. The stools are usually watery or frothy, acidic, and contain lactose. The child's weight usually does not increase, and symptoms such as malnutrition, anemia, and emaciation may occur. Constipation refers to reduced frequency of bowel movements, difficulty in defecating, or hard stools; lactose intolerance usually does not lead to such symptoms.