Why Do I Drool in My Sleep?Causes and When to Check

Waking up to a wet patch on the pillow is embarrassing, but it’s usually ordinary. Drooling simply means saliva leaving the mouth.¹

Why it happens at night

Saliva production is highest while you’re awake and drops dramatically during sleep.² Swallowing still happens during normal sleep.² So nighttime drooling is usually less about making extra saliva and more about saliva escaping:

• An open mouth, often from a blocked nose.
• Sleeping on your side or front, which lets saliva run out instead of back.

In general, drooling comes from one of three routes: trouble keeping saliva in the mouth, trouble swallowing it, or making too much.¹

Things that can add to it

Cause	Why
Blocked nose, allergies, sinus infection	Mouth breathing; allergies and sinus infections can also raise saliva1
Heartburn or reflux	Can increase saliva1
Pregnancy	Extra saliva, sometimes with nausea or reflux1
Certain medicines	Can raise saliva1

The snoring connection

In a survey of 1,000 adults, people who drooled were more likely to snore.³ A blocked nose with mouth breathing was the strongest link to sleep apnea risk: 8 times the odds of high risk.³ It was a questionnaire study, so it can’t diagnose anyone, but drooling plus loud snoring, gasping or daytime sleepiness is worth raising. See why you snore and sleep apnea without snoring.

The other side: a dry mouth

The same open mouth can leave you parched. In a Canadian survey, 23% of people reported waking at night with a dry mouth and reaching for water.² See why you wake up with a dry mouth.

When to check

Call emergency services for drooling with a drooping face, arm weakness or slurred speech: those are stroke signs.⁴

Book an appointment for:

• New or heavy drooling with no clear cause.¹
• Gagging, choking or coughing on saliva.¹
• Drooling with trouble swallowing, or changes in speech or movement. Conditions such as Parkinson’s disease, stroke and ALS can affect swallowing.¹

What helps

1. Treat a blocked nose so you can breathe through it.
2. Try sleeping on your back if your clinician hasn’t advised otherwise; back sleeping can worsen apnea for some people.
3. Note the pattern for two weeks: how often, which position, any snoring a partner hears.
4. Bring your medicine list if drooling started with something new.¹

Try: “I’ve started drooling on my pillow most nights, and my partner says I snore. Could my nose or my breathing at night be part of it?”

Did I Do That in My Sleep? covers this in Chapter 7, “The Pillow, the Water Glass and the Morning Kiss,” in sections called “The Ordinary Pillow Mark” and “When Drooling Changes the Question.” Its Night Map starts with noticing the pattern, so a pillow mark gets matched with snoring, a dry mouth or a new medicine before anyone guesses. See the book.