Experts Explain When Drooling During Sleep Signals Medical Concern

Drooling during sleep is a common phenomenon that usually does not indicate a medical problem, according to sleep experts interviewed by Iris Kol. The most frequent cause is simply breathing through an open mouth while asleep, which allows saliva to escape due to gravity. During REM sleep, when muscles relax significantly, the likelihood of drooling increases, especially if the mouth remains open. Nearly everyone drools occasionally in sleep, but only some leave visible marks on their pillow.

However, experts warn that new, increased, or persistent drooling accompanied by symptoms such as loud snoring, breathing pauses or choking sensations during sleep, extreme daytime fatigue, significant dry mouth upon waking, facial weakness, unclear speech, or difficulty swallowing should prompt medical evaluation. These signs may indicate obstructive sleep apnea, a common sleep disorder linked to higher risks of hypertension, heart disease, and stroke if untreated. In rare cases, neurological issues may be involved when drooling is paired with muscle weakness or speech changes.

Other factors contributing to mouth breathing and drooling include allergies, nasal congestion, a deviated nasal septum, acid reflux, certain medications, and sleeping position. Sleeping on the side or stomach tends to increase drooling, while sleeping on the back reduces it. Despite this, experts advise against changing healthy sleep positions solely due to drooling and recommend addressing the underlying causes instead.