There are three main reasons why three-month-old babies poop green, in general terms. First, dairy products are rich in iron, which is not fully absorbed in time and excreted from the stool, making the stool green. Secondly, the food that the baby eats consumes less bile in the intestines, so the excess bile is discharged from the intestines, making the stools green. Third, inflammation in the intestines or intestinal peristalsis is too fast, so that the bilirubin in the intestines has not been converted, and then discharged from the stool, making the stool green. In more detail, there are mainly the following situations can lead to green stool. 1, breastfed babies are prone to green stool, this is because breastfed babies acidic stool, sometimes in the role of intestinal bacteria, part of the bilirubin into bilirubin, so sometimes discharged stool green. 2, cold, such as babies eat milk or food some cold, or baby’s tummy, feet due to the cold, cold can lead to faster bowel movements. The cold will lead to accelerated intestinal peristalsis, which can lead to green stools. 3, the baby is in a state of hunger, or eat half full, will also lead to accelerated intestinal peristalsis, which causes green stools. 4, the baby to eat iron strengthened formula, eat the milk inside the iron is not fully absorbed, can also lead to green stools. 5, the baby ate too much, or too varied kinds of, is also prone to green stools. When the baby stools appear green, does not necessarily mean that the disease state, must do a good job of abdominal warmth as well as feeding work, try to ensure that the baby has enough milk to eat, as long as the baby milk and mental state can be, there is no frequent difficult to coax abnormal crying, no fever and other abnormal symptoms do not have to worry about, do not have to be special treatment, if necessary, you can send stool to the hospital to give the baby to do routine stool laboratory tests If necessary, you can send your baby to the hospital for routine stool tests to further exclude intestinal bacterial infections.