Why Saliva Ends Up on Your Pillow While Sleeping, Explained by Science

Waking up to find a wet spot of drool on your pillow might seem embarrassing, but science has a surprisingly interesting explanation for it. Saliva leaking from your mouth during sleep, also known as nocturnal drooling, is more common than most people think and it’s often harmless...CONTINUE READING THE FULL ARTICLES HERE

When we sleep, especially during the deep sleep stage (non-REM sleep), our muscles, including those in the face and jaw, relax significantly. This relaxation can cause the mouth to fall open slightly, allowing saliva to escape more easily.

If you sleep on your side or stomach, gravity helps pull saliva out, making it more likely for drool to land on your pillow.

Another common cause is nasal congestion. When your nose is blocked, you’re forced to breathe through your mouth, which can increase drooling.

Medical conditions like acid reflux, allergies, sleep apnea, or neurological disorders can also contribute. Even some medications that relax muscles or increase saliva production may play a role.

In most cases, drooling is nothing to worry about. However, excessive drooling might indicate an underlying issue that requires medical attention.

If it bothers you, try adjusting your sleeping position, treating allergies, or staying hydrated. Your body is simply doing what it’s designed to do—rest and restore.