The reason why children spit bubbles may be a normal phenomenon caused by excessive secretion of saliva, or it may be a symptom caused by pneumonia and other reasons. 1. Physiological phenomenon: Because the development of salivary glands in children is immature at the beginning, so children’s saliva secretion will be less. With the increase of age, the child’s salivary gland secretion will become more and more mature, wait until after 3 months, the baby’s saliva secretion increased significantly, then the child’s oral movements will gradually increase, the child may show spitting bubbles, drooling and other phenomena, which are normal physiological phenomena. As the child’s swallowing function improves and age, these phenomena will disappear on their own. 2. Pneumonia: When a child suffers from pneumonia, he or she may show symptoms such as spitting up bubbles, refusing milk, shortness of breath, chest tightness, poor general condition, or even suffocation. If your child is spitting up bubbles with other symptoms, you need to go to the hospital for a medical checkup in time to avoid delaying your condition.