Two months baby with blood in stool and anal fissure, lactase deficiency, intussusception, allergy and other factors related. 1. anal fissure: two month old babies who have dry stools and cause mechanical damage to the anus during defecation will have blood in their stools. 2. Lactase deficiency: two-month-old babies who are breastfed will experience abdominal pain, diarrhea, and blood in the stool if they lack lactase. 3. Intussusception: If your two-month-old baby has blood in the stool, vomiting and crying at the same time, you need to rule out intussusception. 4. Allergy: If the baby consumes formula, allergy to the ingredients in the formula will cause allergic diarrhea, blood in the stool, vomiting, fever and other symptoms. There may be other reasons for blood in the stool of a two-month-old baby, so it is recommended to go to the hospital and get prompt treatment after clarifying the cause of the disease.