Drooling in two-year-olds is considered to be related to physiological factors, and may also be caused by abnormal central nervous system development, oral ulcers and other factors. 1. Physiological factors, two-year-old children swallowing function is not fully developed, saliva secretion is not swallowed in a timely manner, this symptom may occur. 2. Abnormal central nervous system development, some children have abnormal central nervous system development, resulting in poor swallowing function, which may lead to excessive salivary secretion, and therefore this situation will occur. 3. Mouth ulcers, some children with mouth ulcers after oral sensitivity increases may appear drooling symptoms. Two-year-old children drooling, there may be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.