Three-month-old babies who have green loose stools may have been exposed to cold, resulting in faster bowel movements, and part of the bilirubin will not be converted into fecal bilirubin in time, so the stools will appear green. It is also possible that some of the babies who are taking probiotics may also have green stools. If the stools are not too frequent and not very loose, you can observe, because the color is not the focus of attention, the focus is on the baby’s appetite, spirit, and whether there is bloating. If the stools are really thin, you can take oral probiotics. If the stools are very frequent and long, you should take the stools to the hospital for laboratory tests to see if there is any inflammation in the stools.