Constant swallowing of saliva while sleeping may be caused by oral diseases or related to gastroesophageal reflux. When oral ulcers or periodontitis exists, the oral mucosa due to its own immune response needs to secrete a large amount of saliva containing phagocytes, which will cause unconscious swallowing of saliva during sleep. You can take vitamin supplements or oral metronidazole to promote healing of inflammation, and the symptom of nocturnal gagging will be relieved. Gastroesophageal reflux when the lack of consciousness at night, coupled with the body in a lying position, reflux of gastric fluid into the oral cavity, causing increased secretion of saliva, you can take oral omeprazole, sodium bicarbonate and other mucosal protective agents. Therefore, keep swallowing saliva while sleeping may be mouth ulcers or gastroesophageal reflux, the specific circumstances need to go to the stomatology or gastroenterology department for medical treatment.