Yellow water after spitting up may be caused by indigestion, congenital pyloric obstruction, gastrointestinal dysfunction, gastroesophageal reflux and other reasons. 1. indigestion: feeding babies too much milk, the baby inhaled a lot of air during breastfeeding, may cause the baby’s stomach flatulence, causing gastrointestinal discomfort and thus leading to vomiting. As the infant’s gastrointestinal system is not yet fully developed, vomiting too much may have vomited yellow water. 2. Congenital pyloric obstruction: if the baby suffers from congenital pyloric obstruction, the tension of the pyloric region will be particularly high, the baby can not enter the intestine after drinking milk, there will be spitting up, if the baby spitting up is more serious, there will be spitting up the yellow water, the yellow water spitting up may be bile. 3. Gastrointestinal dysfunction: babies’ own immune system is not perfect, poor gastrointestinal digestive ability, it is easy to have gastrointestinal dysfunction, which will cause abdominal pain, diarrhea, vomiting and other conditions, spitting up milk will be spit out of yellow water in severe cases. 4. Gastroesophageal reflux: due to the lower esophageal sphincter relaxation and decreased ability to contour, reflux, belching (hiccups), etc., can also lead to yellow water after spitting up. Infants with yellow water after spitting up, there may also be other reasons, we should consult the doctor in a timely manner, by the doctor to clarify the specific causes to take relevant treatment, so as to avoid delaying the condition.