Why does my baby's stool have bubbles?

It is normal for a baby's stool to contain foam, which is caused by the baby's immature digestive system. A baby's digestive tract contains a large amount of digestive enzymes that can produce foam during digestion. In addition, lactose intolerance is another common cause—babies may be unable to fully digest the lactose in breast milk or formula, resulting in foamy stools. If a baby's stool consistently contains foam, it is advisable to seek medical attention promptly.