Three-month-old babies suddenly start vomiting milk is not necessarily a cold, may be too much to eat, not enough back patting, indigestion, congenital hypertrophic pyloric obstruction and so on. 1. Eat too much: If the baby eats too much at once when drinking milk, spitting up will occur, and then when breastfeeding can be used to gently press the nipple to control the flow of milk. 2. After feeding did not fully pat the back: if the baby directly after feeding put down will also appear vomiting milk performance, it is recommended that after feeding the baby will be vertical hold up gently pat the back. 3. indigestion: three months of the baby’s digestive system may not be perfect, indigestion will also appear to vomit, can give bifidobacteria to regulate the intestinal tract. 4. Congenital hypertrophic pyloric obstruction: babies will vomit milk almost every time after breastfeeding, and then it is recommended to go to the hospital for ultrasound and other tests to confirm the diagnosis. The baby may also vomit after a cold, and it is recommended that the parents pay attention to keep warm. If your three-month-old baby is vomiting milk, we recommend that you go to the hospital to find out the cause of the vomiting and choose the appropriate treatment plan under the guidance of your doctor.