why saliva comes out of mouth while sleeping
Drooling Drooling or sialorrhea can occur during sleep. It is often the result of open-mouth posture from CNS depressants intake or sleeping on one's side. Sometimes while sleeping, saliva does not build up at the back of the throat and does not trigger the normal swallow reflex, leading to the condition.
Hypersalivation Hypersalivation (also called ptyalism[1] or sialorrhea[2]) is excessive production of saliva. It has also been defined as increased amount of saliva in the mouth, which may also be caused by decreased clearance of saliva.[3]