What happens when the baby vomits as soon as he eats milk

The baby vomits when he eats milk. It is considered that the child has a cold and will spit milk. Or the baby eats too much air in the process of eating. When there is too much gas in the stomach, it will also cause vomiting milk. Secondly, it is also considered that the baby's gastrointestinal function is mature. Eating too much will lead to indigestion and will also cause vomiting milk symptoms.