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

Quick answer: Drooling in your sleep is usually normal. It often happens because you swallow less while sleeping and saliva escapes from your mouth. Your sleep position, mouth breathing, nasal congestion, acid reflux, braces, medication, and some health conditions can also play a role.

Waking up with drool on your pillow can feel embarrassing, but it is usually nothing to worry about. Your body still makes saliva while you sleep, and some of it can escape before you swallow it.

But if drooling happens often, starts suddenly, or makes you wonder whether it could be connected to another sleep or health concern, keep reading. 

This article explains why it happens, what you can do about it, and when it may be worth talking with a healthcare provider.

Is Drooling in Your Sleep Normal?

Yes. Occasional drooling during sleep is normal for many adults.

Your body continues to produce saliva overnight, but you swallow less frequently than you do while awake. Swallowing is infrequent during sleep and may be absent for long periods, particularly in deeper sleep stages. [1]

If saliva collects in your mouth and your lips are open, it can leak onto your pillow. An occasional wet spot on your pillow does not usually mean that you are making too much saliva or have a health problem.

Persistent or excessive drooling is sometimes called sialorrhea or hypersalivation. This is different from occasional nighttime drooling. It is more likely to happen often, affect you during the day, or occur with other symptoms, such as trouble swallowing.

Why Do You Drool When You Sleep? Common Causes

Drooling during sleep can happen when saliva escapes from your mouth more easily, when your body makes more saliva than usual, or when swallowing saliva becomes more difficult.

Your sleep position

Sleeping on your side or stomach can make drooling more likely. Gravity pulls saliva toward the corner of your mouth, where it can escape more easily.

This does not necessarily mean that anything is wrong. It may simply be more noticeable in certain positions. 

Some people find that another comfortable sleep position reduces drooling. But do not force yourself to sleep on your back if it makes snoring, breathing, or sleep comfort worse.

Mouth breathing and nasal congestion

Sleeping with your mouth open gives saliva an easy way to escape.

Some people naturally sleep with their mouths open. But mouth breathing can also happen when it is hard to breathe through the nose. Common reasons include:

• Seasonal allergies

• A cold

• Sinus congestion

• Nasal polyps

• A deviated septum

• Enlarged tonsils or adenoids

If you mainly drool when you have a cold, allergies, or a stuffy nose, it may improve once you can breathe through your nose more comfortably.

Waking up with a dry mouth, dry throat, or open mouth may also suggest that you are mouth breathing during sleep.

Infections and allergies

Allergies and infections can make drooling more likely by blocking your nose, irritating your throat, or making swallowing uncomfortable.

Possible causes include:

• Strep throat

• Tonsillitis

• Mononucleosis

• Sinus infections

• Peritonsillar abscess, a possible complication of tonsillitis

Drooling related to a cold, allergies, or a minor infection often improves as you recover. But severe throat pain, trouble breathing, difficulty swallowing liquids, or worsening swelling needs prompt medical attention.

Braces and other dental appliances

New braces can temporarily make your mouth feel more watery than usual. As your mouth adjusts to brackets and wires, fixed orthodontic appliances can affect saliva flow. [2]

If you also sleep with your mouth open, you may notice more drool on your pillow. For many people, this improves as their mouth gets used to the braces. The same can happen when you first begin using retainers or other dental appliances.

Talk with your dentist or orthodontist if excess saliva continues, is difficult to manage, or occurs with pain, mouth sores, or another dental concern.

Acid reflux

Acid reflux can sometimes increase saliva in your mouth. When acid reaches the esophagus, your body may produce extra saliva as a protective response. This is sometimes called water brash. [3]

Reflux may be contributing to nighttime drooling if you also have:

• Heartburn

• Regurgitation

• A sour or bitter taste in your mouth

• Coughing at night

• Symptoms that worsen after lying down

Heartburn, regurgitation, swallowing problems, and chronic cough can occur with gastroesophageal reflux disease, or GERD. [4]

Talk with a healthcare provider if reflux symptoms are frequent, persistent, or affecting your sleep.

Medication side effects

Some medicines can increase saliva production or make saliva harder to manage. Clozapine, an antipsychotic medication, is one well-known example, and hypersalivation is listed in its prescribing information. [5]

If drooling started after you began a new medication or changed your dose, ask your pharmacist or prescriber whether it could be a side effect.

Do not stop a prescription medication on your own because of drooling.

Sleep apnea

Drooling alone does not mean you have sleep apnea. But it may be worth paying attention to whether you have other signs of disrupted breathing during sleep.

Obstructive sleep apnea happens when the upper airway becomes narrow or blocked repeatedly during sleep. [6] Other possible signs include:

• Loud, frequent snoring

• Gasping or choking during sleep

• Pauses in breathing noticed by someone else

• Waking often during the night

• Morning headaches

• Excessive daytime sleepiness

• Trouble concentrating during the day

If drooling happens along with one or more of the signs above, especially loud snoring, gasping, choking, or witnessed breathing pauses, talk with a healthcare provider about sleep apnea.

Teeth grinding

Teeth grinding, also called sleep bruxism, does not usually cause drooling on its own. But if you grind your teeth and sleep with your mouth open, you may be more likely to notice saliva on your pillow.

Other signs of nighttime teeth grinding include:

• Jaw soreness when you wake up

• Morning headaches

• Sensitive teeth

• Worn or chipped teeth

• A grinding sound noticed by someone else

A dentist can check your teeth and jaw for signs of bruxism. More severe teeth grinding can contribute to tooth damage, jaw pain, tooth sensitivity, and headaches. [7]

Trouble swallowing and neurological conditions

Sometimes drooling happens because you are having difficulty swallowing saliva normally.

Difficulty swallowing is called dysphagia. It can affect food and drinks, but some people also have trouble clearing saliva from their mouth. [8]

Neurological conditions that affect the nerves or muscles involved in swallowing can make drooling more common. These include Parkinson’s disease, stroke, cerebral palsy, amyotrophic lateral sclerosis, and multiple sclerosis. [9]

These conditions are much less likely to explain an occasional wet pillow if you otherwise feel well. But drooling needs medical attention if it also happens while you are awake or comes with coughing, gagging, choking, or difficulty swallowing food or drinks.

Is Drooling a Sign of Deep Sleep?

No, drooling does not mean you slept well or were in deep sleep. You swallow less often while sleeping, but a wet pillow does not show how restful your sleep was. 

You may drool because your mouth was open, your nose was congested, or you slept on your side. You can also sleep deeply without drooling at all.

Also Read: Why Am I Still Tired After 8 Hours of Sleep?

Why Am I Suddenly Drooling in My Sleep?

If drooling is new for you, think about what has changed recently.  

For example, you may have:

• Developed a cold, allergies, or nasal congestion

• Started sleeping in a different position

• Begun mouth breathing at night

• Gotten braces or another dental appliance

• Started a medication or changed your dose

• Noticed more acid reflux

• Started snoring more often

A temporary cause, such as a cold or seasonal allergies, may improve on its own. But if the drooling continues, becomes more frequent, or happens with other symptoms, talk with a healthcare provider.

How Can You Reduce Drooling While Sleeping?

If sleep drooling bothers you or happens often, these steps may help reduce it.

Address nasal congestion

If allergies or congestion are making you breathe through your mouth, treating the underlying problem may reduce drooling.

If you often have a blocked nose, recurring sinus symptoms, or trouble breathing through your nose at night, ask a healthcare provider about possible causes.

Identify mouth breathing

If you wake up with a dry mouth, dry throat, or open mouth, consider whether you may be mouth breathing while asleep.

Focus on why nasal breathing is difficult rather than trying to force your mouth closed. Mouth taping is not a one-size-fits-all solution, particularly for people with nasal blockage, snoring, or possible sleep apnea. In a recent clinical study, closing the mouth improved airflow for some people with obstructive sleep apnea but worsened airflow for a subgroup who primarily breathed through their mouths during sleep. [10]

Manage reflux symptoms

If nighttime drooling happens with heartburn, regurgitation, coughing, or a sour taste in your mouth, managing reflux may help. 

A healthcare provider can help if reflux is frequent, disrupts your sleep, or does not improve.

Review medication changes

If you noticed drooling after starting a new medicine or changing a dose, ask your prescriber or pharmacist whether the medicine may be involved. 

They can help determine whether a change is appropriate while keeping your treatment safe.

Give braces time

If you recently got braces, extra saliva may improve as your mouth adjusts. Check with your orthodontist if it does not improve or if you have other symptoms, such as pain, sores, or trouble eating.

When Should You See a Healthcare Provider?

Occasional nighttime drooling usually does not need medical treatment. But certain patterns may be worth checking.

Persistent daytime drooling can sometimes irritate the skin around your mouth or raise the risk of saliva entering your airway, especially if you also have trouble swallowing.

Get urgent medical help for sudden drooling with facial drooping, one-sided weakness, confusion, trouble speaking, severe trouble swallowing, or trouble breathing.

For persistent drooling related to a swallowing or neurological condition, treatment depends on the cause. It may include swallowing or motor therapy, medicines that reduce saliva, botulinum toxin injections, oral appliances, or surgery in severe cases. 

The Bottom Line

Drooling in your sleep is usually harmless. It often happens because you swallow less while sleeping, sleep with your mouth open, or lie in a position that allows saliva to escape.

But frequent or sudden drooling can be worth checking, especially if it happens during the day or comes with trouble swallowing, coughing or choking, loud snoring, gasping, or breathing pauses.

About the author

Dr. Ruchir P. Patel, MD, FACP, is the Medical Director of the Insomnia and Sleep Institute of Arizona and the founder of Sip2Sleep. He is triple board-certified in sleep medicine, obesity medicine, and internal medicine. Dr. Patel is a multi-year Phoenix Magazine Top Doctor and holds the Inspire Excellence designation.

References

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2. Jakavičė, R., & Žarovienė, A. (2023). Changes in the pH and the Flow Rate of Saliva During Orthodontic Treatment with Fixed Orthodontic Appliances: A Systematic Review. Turkish journal of orthodontics, 36(3), 199–207. https://doi.org/10.4274/TurkJOrthod.2022.2022.66

3. Helm, J. F., Dodds, W. J., & Hogan, W. J. (1987). Salivary response to esophageal acid in normal subjects and patients with reflux esophagitis. Gastroenterology, 93(6), 1393–1397. https://doi.org/10.1016/0016-5085(87)90270-8

4. National Institute of Diabetes and Digestive and Kidney Diseases. (2020, July). Symptoms & causes of GER & GERD. National Institutes of Health. https://www.niddk.nih.gov/health-information/digestive-diseases/acid-reflux-ger-gerd-adults/symptoms-causes

5. Mylan Institutional Inc. (2025, July 18). Clozapine tablet, orally disintegrating. DailyMed. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=976be6e3-a9db-49c6-9b02-1ab168cf17b1

6. National Heart, Lung, and Blood Institute. (2025, January 9). Sleep apnea - symptoms. National Institutes of Health. https://www.nhlbi.nih.gov/health/sleep-apnea/symptoms

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