There are many reasons that cause babies who eat milk powder to have green poop, such as immature digestive system, babies catching cold, and eating milk powder containing iron. 1. immature digestive system: the baby is young, the development of digestive organs is not mature enough, the secretion of digestive juices is not enough, the function of digestive enzymes is not perfect, affecting the digestive ability, resulting in gastric dysfunction, there will be a bloated tummy, stool green and other manifestations. 2. baby cold: if the baby usually do not do a good job of warmth, resulting in the abdomen is cold, there may be overflow of milk, the phenomenon of green stool, so usually pay attention to warmth, to avoid getting cold. 3. Eat iron milk powder: If the baby usually eat milk powder contains iron, the baby’s digestive system is not good enough to fully absorb the iron in the milk powder, there will be a green stool. If the symptoms are not relieved, it is recommended to go to the hospital for examination in time.