Green stools in four-month-old babies may be related to feeding problems or may be caused by indigestion, acute gastroenteritis and other reasons. 1. Feeding problems: If breastfeeding, the mother of a large number of dark-colored food or food rich in green pigments, may lead to the baby stools green. If the baby is formula-fed, the formula is rich in iron, which can also cause the baby’s stools to be green. These are physiological factors that do not require special intervention. 2. Indigestion: If parents do not feed properly, or the baby’s abdomen is cold, it is easy to cause the baby’s gastrointestinal peristalsis speed up, resulting in increased intestinal secretion, which may cause green stools, may also be accompanied by abdominal distension, abdominal pain and other symptoms. 3. Acute gastroenteritis: four months of the baby ate spoiled breast milk or milk powder, is likely to induce acute gastroenteritis, due to the presence of gastrointestinal tract inflammation and infection, may cause green stools, may also be accompanied by increased stool frequency, abdominal pain and other symptoms. Four-month-old babies with green stools may also be caused by other reasons, if accompanied by other uncomfortable symptoms, you should consult a doctor as soon as possible, after diagnosis of the cause, to give targeted treatment.