Spitting up in a 40-day-old child is a frequent occurrence and happens in many children. If the spitting up is not serious, you can burp your child after feeding to expel the gas that enters the stomach to reduce the spitting up. After spitting up, the child should be cleaned up in time to avoid aspiration pneumonia or even suffocation caused by inadvertent aspiration into the respiratory tract. Do not feed your child immediately after vomiting, but wait until the child is stable before feeding. If your child is spitting up violently, burp him/her well after feeding, and then pay attention to elevating the upper half of the child’s body when putting him/her down, about 30 degrees. If your child is vomiting heavily and is not gaining weight satisfactorily, you should pay attention to other diseases, such as congenital hypertrophic pyloric stenosis, and go to the hospital to improve the digestive system imaging to confirm the diagnosis.