Introduction: drooling when the baby sleeps may be caused by improper sleeping position, such as sleeping on the table, sleeping in the side position, are prone to drooling. However, if this is the case for a long time, it may be a signal of some diseases. 1, poor oral hygiene The temperature and humidity in the oral cavity are most suitable for the reproduction of bacteria, and the accumulation of food residues or sugar substances on the teeth and tooth surfaces can easily cause tooth decay and periodontal disease. Inflammation in the oral cavity will promote saliva secretion. If the mouth is infected by bacteria and the pain is obvious and drooling is easy, topical medication is needed to promote the healing of ulcers. If the salty taste and yellowish color of the saliva flowing out when sleeping is likely due to poor oral hygiene and accumulation of food residues, resulting in more tartar and inflammation of the gums. 2, front teeth malformation Dental malformation is one of the main reasons for drooling in bed. Especially patients with convex malocclusion, whose front teeth protrude more obviously, often appear open lips and teeth, it is difficult for the lips to completely cover the front teeth when sleeping, the upper and lower lips often naturally separate, it is easy to drool. Such patients should correct their teeth as soon as possible. 3, neuromodulation disorders In addition to the above oral problems, there are some systemic diseases that may also cause drooling in bed. The regulation of salivary secretion is completely neuro-reflexive, the so-called “hope to quench thirst” is an example of the conditioned salivary secretion in daily life. Therefore, neurological disorders can also lead to drooling during sleep. Some patients with neurosis or other systemic diseases that may cause disorders of the vegetative nerves will experience abnormal sympathetic excitement during sleep, resulting in the brain to send the wrong signal, causing increased saliva secretion. 4, drug factors For example, one of the side effects of taking certain anti-epileptic drugs is drooling.