1. Reasons why six-month-old babies spit up milk 1.1 The baby eats too fast 1.2 The baby eats too much 1.3 The baby’s digestion is not fully developed Six-month-old babies are in a period of rapid growth and development, and their nutritional needs are getting higher and higher. However, some babies will spit up milk when eating, which makes parents very worried. So why does this happen? First of all, it may be because