The reason why a one-month-old baby has green stools may be related to hunger reasons, medication factors, indigestion and so on. 1. hunger factor: for some babies, may produce hunger green stool, mainly the baby in the state of excessive hunger, the intestinal biliverdin can not be converted to bilirubin out of the body, so the stool will show green phenomenon. 2. drug factors: a month baby pulling green stools can not be ruled out and drug factors, such as taking iron, iron is metabolized in the body, the formation of black-green iron sulfide, so the baby will show after defecation dark green stool symptoms. 3. indigestion: this is also the cause of more than one month baby green stool, may be due to improper care, resulting in indigestion. In the case of abdominal cold, because the gastrointestinal tract peristalsis accelerated, the food is not fully digested out of the body, will also produce green stools. There may also be other causes of green stools in one-month-old babies, so it is important to identify them as soon as possible and give them targeted treatment and therapy.