Three-month-old babies with green stools may be cold, not eaten enough, eat iron formula and other factors. 1. Cold: three months of the baby flora development is not perfect, and its own intestinal peristalsis is relatively fast, if the cold may bring out the body of the bile, the stool will show green. 2. did not eat enough: the baby if not eat enough, coupled with fast intestinal peristalsis, may lead to the intestinal bilirubin is not converted, it is discharged from the stool, presenting green stools. 3. ate iron containing milk powder: three months baby if eaten iron containing milk powder, resulting in not fully absorb the iron in the milk powder, will also appear green or dark green stool. Three months of the baby’s green stool may have other reasons, it is recommended to go to the hospital in a timely manner to carry out relevant examinations to clarify the cause of the disease and actively treat the symptoms.