Drooling in bed is a common physiological phenomenon in infancy, because the infant’s facial muscles are not yet well developed, chewing ability is weak, not yet able to regulate the excess fluid in the mouth, often sleep drooling symptoms; adults mostly because of incorrect sleeping posture, side lying, lying on their stomach to compress the parotid gland, easily lead to sleep always drooling. In addition, also common in the following pathological reasons: 1, oral inflammation: such as periodontitis, oral ulcers, etc., inflammation in the mouth easy to promote saliva secretion, oral bacterial infection may cause pain, resulting in sleep always drooling; 2, dental malformation: some patients with dental malformation, the front teeth protrude forward, the lips can not completely cover the front teeth when sleeping, the upper and lower lips naturally separate, easily lead to sleep drooling; 3 Facial neuritis: often caused by cold, wind or upper respiratory tract infection caused by facial neuritis, resulting in crooked corners of the mouth, poor closure, salivation and other symptoms appear, also seen in the stroke aura, often appear to sleep drooling symptoms; 4, nerve excitement: excessive fatigue or taking certain drugs may appear parasympathetic excitement, stimulating saliva secretion increases, appear to sleep always drooling symptoms; 5, gastrointestinal function Disorders: such as gastrointestinal motility disorders, may cause patients to increase saliva, resulting in sleep always drooling; 6, cerebrovascular lesions: such as cerebral infarction, cerebral atrophy, easily lead to the relaxation of facial muscles, as well as the ability to swallow weakened, can appear to sleep always drooling symptoms, common in the elderly; 7, other: such as Parkinson’s, Alzheimer’s, cerebral palsy and other serious cases, can also appear to sleep always drooling symptoms .