Children always spit may be physiological phenomena, bad habits, mouth ulcers and other reasons. 1. Physiological phenomenon: If the child is in the period of eruption, the process of tooth growth, the child feels uncomfortable, there may be always spitting. 2. Bad habits: If the child does not have a disease, but always spit, may be the child’s sense of fun, the development of bad habits. 3. Mouth ulcers: children have ulcers in the mouth, inflammation stimulation can lead to increased salivary secretion, and mouth ulcers are more painful, the child is afraid to swallow saliva, which led to the emergence of the old spit. Children always spit, may also be other causes, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, give targeted treatment or standardized treatment.