There are many reasons why babies change milk powder to green poop, such as iron in milk powder, indigestion, and other factors. 1. Iron in milk powder: If the new milk powder contains iron, it can cause the baby to change milk powder to green poop. 2. indigestion: the baby’s gastrointestinal function is not yet fully developed, so the change of milk powder due to the lack of adaptation, may have indigestion, which will lead to the phenomenon of the baby’s change of milk powder green stools. 3. other factors: the baby change milk powder green stools may have nothing to do with milk powder, may be due to the intake of green leafy vegetables, such as spinach, cabbage and so on, will cause the phenomenon of green stools. There are a lot of reasons why babies change their milk powder to green stools, and if they are accompanied by other discomforts or symptoms that cannot be relieved for a long time, it is recommended that they go to the hospital in a timely manner and follow the doctor’s instructions to carry out standardized treatments, so that they do not ignore the symptoms and take them lightly.