Newborns with blood in their stools can be caused by acute gastroenteritis and lactose intolerance. 1. Acute gastroenteritis: due to the newborn’s gastrointestinal mucosal barrier function is relatively weak, caused by bacterial and viral infection of the newborn’s gastrointestinal tract will appear diarrhea with blood, vomiting, fever. 2. Lactose intolerance: newborns with blood in the stool may also be due to the lack of lactase enzyme is not able to fully digest the lactose in dairy products, the patient will also have abdominal distension, crying and other symptoms. Newborns with blood in the stool may also have other causes, such as digestive protein allergies, etc., it is recommended to go to the hospital, complete the examination to determine the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.