The causes of drooling in sleep and speech include disease, physiological causes, drug causes, environmental causes and others. 1. Disease causes: facial neuritis, there will be a crooked mouth, drooling, facial paralysis, etc.; craniocerebral diseases, such as cerebral thrombosis, Alzheimer’s disease, etc., there will be a crooked mouth, eyes slant, drooling and other phenomena; oral diseases, dental caries, gingivitis, salivary neuromodulation dysfunction, etc., will lead to salivary secretion disorders, the mouth corner of the closure of the difficulty, caused by sleeping drooling, talking and also drooling. 2. Physiological reasons: newborns and young children, due to the incomplete development of the nervous system, due to the incomplete closure of the corners of the mouth, can lead to sleep drooling and drooling. 3. Drug reasons: taking anti-anxiety drugs, sedative drugs, anesthesia drugs, such as Valium, Phenobarbital, etc., will have the side effect of drooling. 4. Environmental causes: High ambient temperature, smell of food around, etc. can also cause drooling. 5. Other: food is difficult to digest, stimulate excessive salivary secretion, can cause drooling; sleep side position, resulting in poor breathing, can also cause sleep drooling; overworked during the day, sleep well at night, open-mouth breathing, etc., can also cause sleep drooling. Therefore, there are more reasons for drooling in sleep and drooling in speech, and patients should consult the doctor in time to clarify the cause of the disease and get early treatment so as not to delay the condition.