what cause drooling out of the side of your mouth
Drooling can be caused by excess production of saliva, inability to retain saliva within the mouth (incontinence of saliva), or problems with swallowing (dysphagia or odynophagia). There are some frequent and harmless cases of 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.