Quick Answer: Drooling in sleep (sialorrhea) is common and usually harmless. The most frequent causes are sleeping on your side, nasal congestion that forces mouth breathing, certain medications, and relaxed facial muscles during deep sleep. Simple fixes , nasal strips, side-sleeping pillows, or a different pillow loft , resolve most cases. Persistent or sudden-onset drooling with other neurological symptoms warrants a doctor visit.
In This Guide
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Medical disclaimer: This article provides general information and is not a substitute for medical advice. If drooling onset is sudden or accompanied by slurred speech, facial asymmetry, or neurological symptoms, seek immediate medical attention.
Why Do We Drool in Sleep?
Your salivary glands produce roughly 1–2 litres of saliva per day. During the day, you swallow constantly , usually unconsciously. When you sleep, swallowing slows dramatically. The muscles of the face, jaw, and throat relax. If saliva accumulates faster than the slowed swallowing reflex can handle, and if your mouth is open or slightly open, gravity does the rest.
Drooling during sleep is technically called nocturnal sialorrhea. Most people experience it occasionally; some experience it regularly. In most cases, it reflects normal physiology rather than anything concerning.
Common Causes
1. Sleep Position
Side and stomach sleeping are the most common contributors to drooling. When you're on your side, saliva pools in the lower cheek and mouth corner and exits by gravity. Back sleeping is the least likely position to cause drooling because saliva drains toward the throat rather than out of the mouth.
2. Mouth Breathing
If your nose is even partially blocked , from seasonal allergies, a cold, deviated septum, or nasal polyps , you compensate by breathing through your mouth during sleep. An open mouth allows saliva to escape. This is one of the most actionable causes because addressing the nasal obstruction (even with a simple nasal strip) often resolves the drooling.
3. Medications
Certain common medications increase saliva production or reduce muscle tone, leading to more drooling during sleep. According to a 2020 review in Current Drug Safety, the most commonly implicated medication classes include:
- Antipsychotics , particularly clozapine
- Certain antidepressants and mood stabilisers
- Cholinesterase inhibitors (used in dementia treatment)
- Some anticonvulsants
- Muscle relaxants
If you've started a new medication and noticed increased drooling, discuss it with your prescribing physician. Do not stop medication without medical advice.
4. Deep Sleep / Sleep Stage
During deep non-REM sleep (slow-wave sleep), muscle activity throughout the body is reduced. The muscles that normally keep your mouth closed and support swallowing are no less subject to this relaxation. People with more time in deep sleep , including many young adults and those who are sleep-deprived , may drool more.
5. Teething and Infants
Excessive drooling in infants and toddlers is normal and developmental. Infants don't develop efficient swallowing coordination until 18–24 months. Teething further increases saliva production. This is not a concern unless accompanied by other symptoms.
Is Drooling a Sign of Good Deep Sleep?
There's a popular belief that drooling means you're sleeping deeply. Technically, it's not a reliable indicator , it's more about muscle relaxation, sleep position, and mouth breathing than sleep depth specifically. However, if you're regularly reaching deep slow-wave sleep (usually in the first third of the night), your muscles are maximally relaxed, which can contribute. A mattress that allows your body to relax fully , without pressure points keeping you tense , supports deeper sleep stages. Research in Sleep Medicine (Tononi & Cirelli, 2003) links comfort and reduced pain to longer slow-wave sleep durations.
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When It May Signal Something More
In most adults, drooling during sleep is benign. However, sudden onset or worsening drooling , especially alongside other symptoms , can occasionally signal a medical issue worth investigating.
Consult a doctor if drooling is accompanied by:
- Slurred speech or difficulty swallowing when awake
- Facial asymmetry or weakness (could indicate stroke or Bell's palsy)
- Tremor or muscle stiffness (early Parkinson's disease can affect swallowing)
- New-onset in an older adult with no change in medications
- Excessive daytime sleepiness suggesting a sleep disorder like sleep apnea
These associations are worth knowing, but they are not common causes of typical nocturnal drooling. Most drooling in otherwise healthy adults is positional or congestion-related.
How Sleep Position Affects Drooling
Position is the most directly controllable factor. Here's how each position affects drooling:
| Position | Drooling Risk | Reason | Notes |
|---|---|---|---|
| Back sleeping | Low | Saliva drains toward throat, swallowed not expelled | Best position for reducing drooling; may increase snoring |
| Side sleeping (left or right) | High | Gravity pulls saliva toward the lower corner of the mouth | Most common sleep position in adults; pillow loft matters |
| Stomach sleeping | Very high | Face often turned to one side; saliva exits directly | Also the worst position for neck and spine alignment |
If side sleeping is your preferred or necessary position (as it often is for people with back pain, acid reflux, or snoring), the goal is to optimise the position rather than change it entirely. The right pillow height keeps your jaw slightly elevated and your mouth closed more naturally.
How to Stop Drooling in Sleep
Address Nasal Congestion
This is often the single most effective fix. Options include:
- Nasal strips (Breathe Right) , expand nasal passages physically, no medication needed
- Saline nasal rinse before bed (neti pot or squeeze bottle) , clears allergens and mucus
- Nasal corticosteroid spray (e.g., Flonase, Avamys) , for chronic allergies, available OTC in Canada
- HEPA air purifier in the bedroom , reduces airborne allergens
- Keeping bedroom humidity between 40–50% , dry air irritates nasal passages
Adjust Your Sleeping Position
If you're a side sleeper and want to try back sleeping, a body pillow behind your back can discourage rolling. If you must side sleep, a contoured pillow that keeps your jaw slightly raised and your head well-supported reduces the pooling effect.
Treat Allergies
Seasonal and year-round allergies are a major driver of chronic mouth breathing during sleep. If you've never been assessed for allergies, an allergist referral through your Brantford family doctor is worth considering if drooling is persistent and connected to congestion.
Chin Strips or Chin Strap Devices
These keep the jaw gently closed during sleep. Some CPAP users already use them to prevent mouth breathing with their therapy. They're available in pharmacies and online , adhesive chin strips are the less intrusive option for non-CPAP users.
Pillow and Bedding Tips
Your pillow affects both sleep position and how much drooling gets absorbed. A few practical considerations:
- Pillow height (loft): Side sleepers need a higher pillow that fills the space between the ear and shoulder, keeping the neck neutral and the head level. Too-flat pillows tilt the head down and open the jaw. Dorothy at our showroom can help assess the right loft for your shoulder width.
- Pillow covers: A waterproof or moisture-wicking pillow protector is worth using if drooling is regular. Cotton percale dries faster than sateen; bamboo-blend covers wick moisture effectively.
- Pillow material: Latex and memory foam hold shape better than down for side sleepers, maintaining consistent head elevation throughout the night. Down compresses and can leave you with a flat pillow by 3 a.m.
Talia Grose, sleep specialist, Mattress Miracle: "We carry pillow protectors in both waterproof and moisture-wicking versions. If drooling is a regular issue, a protector extends the life of the pillow significantly , regular saliva contact breaks down fill materials over time. It's one of those small things that makes a difference to pillow longevity."
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Call 519-770-0001Frequently Asked Questions
Is drooling in sleep normal for adults?
Yes, it's common and usually normal. Most adults drool occasionally, particularly when sleeping on their side, when congested, or in deep sleep. Regular drooling in otherwise healthy adults without other symptoms is almost always positional or congestion-related rather than a medical issue.
Can drooling in sleep cause any harm?
In most cases, no. Drooling itself is harmless. The main practical issue is dampness affecting your pillow's fill material and fabric over time. A waterproof pillow protector is the practical solution. In rare cases of very significant drooling (such as medication-induced), skin irritation around the mouth corner can develop from chronic moisture , barrier cream at bedtime resolves this.
Why do I suddenly drool more at night?
Sudden onset or increase in drooling warrants attention. Common recent-onset causes include new medications, nasal congestion from a new allergy or infection, a change in sleep position, or weight gain affecting airway and jaw position during sleep. If the change is sudden and you also notice slurred speech, facial drooping, or difficulty swallowing when awake, seek medical attention promptly as these can be signs of a neurological event.
Does a better mattress reduce drooling?
Not directly , drooling is primarily driven by position, nasal congestion, and muscle relaxation. However, a mattress that properly supports your preferred sleep position (adequate shoulder relief for side sleepers, proper spinal alignment) reduces the unconscious tossing and position changes that can open the jaw and increase drooling. If you're sleeping on an uncomfortable surface and constantly shifting positions, you're less likely to maintain a jaw-closed position throughout the night.
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