Why does my baby have green stools and constipation when drinking formula milk?

Green stools and constipation in infants consuming formula milk may be caused by the following factors: 1. Inappropriate formula composition: The formula may contain large-molecule substances such as soy protein or casein, or have a high sugar content. These components can lead to accumulation of large molecules in the infant's intestines, causing indigestion, which in turn results in constipation and green stools. 2. Improper feeding practices: Feeding too much or too little formula at one time may disrupt normal intestinal function, increasing intestinal motility and leading to green stools. 3. Lactose intolerance: If the infant has lactose intolerance or cow's milk protein allergy, this may also cause green stools accompanied by constipation. 4. Indigestion: An infant's gastrointestinal system is still developing. Excessive formula intake may cause formula buildup in the intestines, leading to indigestion and resulting in constipation and green stools.