Newborns 28 days pull green poop, usually due to dietary factors resulting in physiological phenomena, such as underfeeding, diet containing iron, etc., but also may be indigestion and other pathological factors caused. 1. Insufficient feeding: newborns are underfed, resulting in not eating enough, hunger makes intestinal peristalsis accelerate, and intestinal fluids and bile are discharged together, resulting in the formation of green stools. 2. Diet containing iron: newborns drink milk powder containing iron, iron is not fully absorbed by the newborn, can also lead to green stools. 3. Indigestion: Newborns suffer from indigestion, which can lead to nutrients being excreted before they are fully absorbed, and can also lead to the formation of green stools, which are usually quite dilute. Newborns 28 days green poop, there may be other reasons, it is recommended to go to the hospital, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.