Blood in the stool of a newborn baby may be related to coagulation disorders, allergic enteritis, necrotizing small bowel colitis, intussusception and other causes. 1. Coagulation dysfunction: It may be thrombocytopenia or hemophilia, etc. Blood in the stool due to coagulation dysfunction. The baby may also have skin petechiae and ecchymosis. 2. Allergic enteritis: Some babies are allergic to milk protein, causing food intolerance. Allergy will cause edema, hemorrhage and necrosis of the intestinal wall, causing blood in the stool. 3. Necrotizing small bowel colitis: due to intestinal infection or ischemia of the intestinal mucosa, the intestinal mucosa is destroyed, resulting in bloody stools, which may be accompanied by drowsiness, refusal to eat and other symptoms. 4. Intussusception: early for crying, vomiting, later manifested as bloody stools, may be accompanied by abdominal masses. Just a month old baby with blood in the stool can also be seen in other causes, it is recommended to consult a doctor in a timely manner, follow the doctor’s instructions for relevant examinations, with the help of the doctor to clarify the cause, and targeted treatment or treatment.