Whether it is normal for a 9-month-old baby to suddenly have 4 or 5 bowel movements cannot be generalized. It may be caused by normal physiological factors, but it may also be caused by indigestion, acute enteritis and other diseases, disease factors caused by the abnormal phenomenon. 1. Physiological factors: breastfed babies, if 9 months suddenly eat a lot of breast milk, there may be a short period of time 4, 5 times, triggering breastfeeding diarrhea, but generally soft golden yellow stool, the baby will not have other discomfort. 2. indigestion: 9 month old babies digestive ability is relatively weak, suddenly eat a lot of protein or difficult to digest food, there may be a short period of time to increase the frequency of stools. The nature of the stool is generally not particularly dilute, and there is no mucus, pus or blood. 3. Acute enteritis: viral and bacterial infections can cause sudden acute enteritis in 9-month-olds, manifested by abdominal pain, diarrhea, vomiting, fever, stools can be watery or mucus-pus-blood, and increased frequency. 9-month-old infants suddenly poop 4, 5 times, there are other reasons, it is recommended to consult a doctor in a timely manner, improve the examination, rule out abnormalities, and if necessary, active treatment.