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What is Drooling? [1]

Drooling, or slobbering, is the flow of saliva outside the mouth. Drooling can be caused by excess production of saliva, inability to retain saliva within the mouth (incontinence of saliva), or problems with swallowing (dysphagia or odynophagia). There are some frequent and harmless cases of drooling – for instance, a numbed mouth from either Orajel, or when going to the dentist.

Hypersalivation or ptyalism (aka sialorrhoea) is excessive saliva production and may result in involuntary loss of saliva from the mouth – drooling. The pathophysiology of sialorrhoea is often not clear, and in some cases, it is thought to be due to a poor swallowing mechanism and inadequate rate of swallowing rather than increased saliva production[2].

Isolated drooling in healthy infants and toddlers is normal and may be associated with teething[3]. It is unlikely to be a sign of disease or complications. Drooling in infants and young children may be exacerbated by upper respiratory infections and nasal allergies.

Some people with drooling problems are at increased risk of inhaling saliva, food, or fluids into their lungs, especially if drooling is secondary to a neurological problem. However, if the body’s normal reflex mechanisms (such as gagging and coughing) are not impaired, this is not life-threatening.

The glands that make your saliva are called the salivary glands. Humans have six glands. They are located on the bottom of the mouth, in your cheeks, and near your front teeth. These glands typically produce two to four pints of saliva a day. When these glands make too much saliva, drooling may be experienced. Drooling is normal in the first two years of life. Infants don’t often develop full control of swallowing and the muscles of the mouth until they are between 18 and 24 months old. Babies might also drool when they’re teething. Drooling is also normal during sleep.[4] Most people drool every once in a while, and it is especially common while sleeping when we swallow less frequently. This can cause saliva to accumulate and seep from the sides of the mouth[5].

Drooling or sialorrhea can occur during sleep. It is often the result of open-mouth posture from taking CNS depressants[6] or sleeping on one’s side. Sometimes, while sleeping, saliva does not build up at the back of the throat and does not trigger the normal swallow reflex, leading to the condition. A sudden onset of drooling may indicate poisoning – especially by pesticides or mercury – or a reaction to snake or insect venom. Excess capsaicin[7] can cause drooling as well, an example being the ingestion of particularly high Scoville Unit chilli peppers.

Some neurological problems cause drooling. Medication can cause drooling due to primary action or side effects; for example, Orajel, the tooth/gum-related medication, can numb the mucosa[8].

Causes[9] of drooling include:

  • exercise, especially cardiovascular exercise
  • stroke and other neurological pathologies
  • intellectual disability
  • autism
  • adenoid hypertrophy
  • cerebral palsy[10]
  • amyotrophic lateral sclerosis
  • tumours of the upper aerodigestive tract
  • Parkinson’s disease[11]
  • rabies
  • mercury poisoning
  • age
  • diet
  • neurological disorders
  • medical conditions such as acid reflux and pregnancy can increase saliva production
  • allergies, tumours, and above-the-neck infections such as strep throat, tonsil infection, and sinusitis can all impair swallowing

Drooling[12] associated with fever or trouble swallowing may be a sign of an infectious disease, including:

Causes of drooling in older adults
There are many potential causes of drooling. Some people sleep in a position that leaves their mouths open.

Others may have underlying conditions, such as[13]:

Excess saliva production: Some people produce extra saliva. While this can be linked to a number of other conditions, there is not necessarily another cause. Hypersalivation makes it difficult to swallow saliva as it is produced, potentially leading to drooling.

Medication side effects: Some medications can lead to hypersalivation, particularly medications for psychiatric disorders or Alzheimer’s disease.

Stroke: Strokes can weaken the muscles around the mouth, making it hard to swallow or keep the lips firmly closed when at rest. This can cause saliva to leak out of the mouth. In older adults with sudden onset drooling, a stroke may be the cause.

A comprehensive treatment plan depends on the cause and incorporates several stages of care: correction of reversible causes, behaviour modification, medical treatment, and surgical procedures.

Atropine sulfate tablets are used in some circumstances to reduce salivation. The same for anticholinergic drugs, which can also be a benefit because they decrease the activity of the acetylcholine muscarinic receptors and can result in decreased salivation. Doctors may prescribe them in conjunction with behaviour modification strategies. Other drugs used are glycopyrrolate and botulinum toxin A – botox injection in salivary glands to diminish saliva production.[15]

Surgical procedures are generally considered after a clear diagnosis of the cause and evaluation of non-invasive treatment options. Severe cases can sometimes be treated by surgical intervention – salivary duct relocalisation, or in extreme cases, resection of salivary glands.

A variety of techniques can treat drooling. Some are more successful than others, but treatment depends on the individual. You will need an ear, nose and throat examination before choosing a treatment. Treatments can include[16]:

  • rewarding or prompting to encourage swallowing
  • exercises to increase muscle tone, improve oral-motor function and sensory awareness
  • drugs that dry up saliva
  • Botulinum toxin injections to help prevent and control drooling
  • surgery to move the gland so that saliva moves towards the back rather than the front of the mouth
  • in extreme cases, the removal of a salivary gland
  • Radiation therapy, reserved as a last resort option, can reduce drooling in severe cases. In some studies, a single fraction of radiation treatment was enough to show marked improvement.[17]

Speech and occupational therapists teach positioning and posture control to help improve lip closure and swallowing. Therapists will work with a patient to improve muscle tone and saliva control and may also suggest that you see a dietitian to modify the amount of acidic foods in your diet.[18] Healthline[19] also says:

  • A special device placed in the mouth helps with lip closure during swallowing. An oral prosthetic device, such as a chin cup or dental appliances, may help with lip closure and tongue position and swallowing. This option works best if you have some swallowing control.
  • Certain medications help reduce saliva production. These include:
  • Scopolamine (Transderm Scop), which comes as a patch and is placed on your skin to deliver the medication slowly throughout the day. Each patch lasts for 72 hours.
  • Glycopyrrolate (Robinul), which is given as an injection or in the form of a pill. This medication decreases your saliva production but can cause dry mouth as a result.
  • Atropine sulfate, which is given as drops in the mouth (usually used for people during end-of-life care).

Side Effects of Medications[20]
Sometimes, certain medications can increase the amount of saliva your body produces, especially if you take medicines for:

The type of medical specialist you see depends on the specific medication and why the medication was prescribed.

For example, if the medication was prescribed for depression, you may see a behavioural health specialist who can discuss other possible treatment options. If it was prescribed for Alzheimer’s disease, a neurologist might be the best fit. If you aren’t too sure, starting with your GP or pharmacist might be best.

The best ways to stop drooling
According to MedicalNewsToday[21], the best ways to stop drooling are:

  • Change sleeping positions
  • Treat allergies and sinus problems
  • Take medication
  • Receive Botox injections
  • Attend speech therapy
  • Use an oral appliance
  • Have surgery

Parkinson’s Disease (PD) and Drooling[22]
Excessive drooling is a common symptom of Parkinson’s and can cause awkwardness in social situations. It ranges from mild wetting of the pillow during sleep to embarrassing outpourings of saliva during unguarded moments. For example, this can happen when the head is down, the mouth is held open involuntarily (as happens in advanced PD) or when a person is engaged in an activity and is distracted from the need to swallow automatically.

Drooling, along with speech and swallowing issues, is included among non-movement symptoms even though the root cause is motor: decreased coordination, slowness of movement (bradykinesia) and rigidity of the mouth muscles and throat.

PD causes a reduction in automatic actions, including swallowing, creating an inability to manage the flow of saliva in and around the mouth. With PD, the amount of saliva the body usually produces is normal, but swallowing difficulties – swallowing less often or not completely – lead to saliva pooling in the mouth.

Severe drooling indicates a serious difficulty with swallowing (dysphagia), which can cause the person affected to choke on food and liquids and can even lead to aspiration pneumonia[23].

Managing Drooling
If you are having problems with drooling, you might consider an appointment with a speech-language pathologist. These professionals can perform a swallow test to diagnose any difficulties and can also give you some strategies to help with drooling.

Sources and Further Reading

22/365 - Fell Asleep
Picture Credit:22/365 – Fell Asleep” by Marloes* is licensed under CC BY-NC-SA 2.0.

CAUTION: This paper is not medical advice. No advice is implied or given in articles published by us but is only for general information. You should always seek the advice of your GP or other qualified health provider with any questions you may have regarding a medical condition. This paper is compiled from the sources stated but has not been medically reviewed. It should never be used as a substitute for obtaining advice from a salivary gland specialist, a physician who specialises in treating ear, nose, and throat (ENT) conditions or other qualified clinician/medical practitioner. If you have already been given dietary advice, you should not make changes without first talking to your GP, consultant or dietitian. Any medications mentioned may include names for US drugs which may have a different name to those available in the UK. The facts are believed to be correct as at the date of publication, but there may be certain errors and omissions for which we cannot be responsible. There is no implied endorsement or promotion of any organisation by the writer. The hyperlinks were valid at the date of publication.


  1. Source (unless otherwise shown):

  2. Source: NHS – © Crown Copyright acknowledged

  3. Source: Common Baby Teething Symptoms & Signs Kute Keiki.

  4. Source:

  5. Source:

  6. Explanation: Central Nervous System (CNS) depressants are medicines that include sedatives, tranquilizers, and hypnotics. These drugs can slow brain activity, making them useful for treating anxiety, panic, acute stress reactions, and sleep disorders. Examples of CNS depressants are benzodiazepines, barbiturates, and certain sleep medicines.

  7. Explanation: Capsaicin is an active component of chilli peppers, which are plants belonging to the genus Capsicum. It is a chemical irritant for mammals, including humans, and produces a sensation of burning in any tissue with which it comes into contact. Source:

  8. Explanation: Mucosa is another name for mucous membrane. It is a moist internal lining of the body such as the mouth, throat, nasal passages, eyelids, intestines and vagina. Source: Source: © Crown Copyright acknowledged

  9. Sources: and

  10. Source: Weiss-Lambrou, R.; Tetreault, S.; Dudley, J. (1989). “The relationship between oral sensation and drooling in persons with cerebral palsy”. American Journal of Occupational Therapy. 43 (3): 155–161.

  11. Source: Kalf, J.G. (2009). “Prevalence and definition of drooling in Parkinson’s disease: A systematic review”. Journal of Neurology. 256 (9): 1391–1396.

  12. Source:

  13. Source:

  14. Source:

  15. Sources: (1) Ellies Maik (2004). “Reduction of salivary flow with botulinum toxin: Extended report on 33 patients with drooling, salivary fistulas, and sialadenitis”. The Laryngoscope. 114 (10): 1856–1860, (2) Lipp, A.; Trottenberg, T.; Schink, T.; Kupsch, A.; Arnold, G. (2003). “A randomized trial of botulinum toxin A for treatment of drooling”. Neurology. 61 (9): 1279–1281, and (3) Mier, Richard J.; Bachrach, Steven J.; Lakin, Ryan C.; Barker, Tara; Childs, Judith; Moran, Maria (2000). “Treatment of Sialorrhea With GlycopyrrolateA Double-blind, Dose-Ranging Study”. Archives of Pediatrics & Adolescent Medicine. 154 (12): 1214–8.

  16. Source:

  17. Source:

  18. Source:

  19. Ibid

  20. Source:

  21. At:

  22. Source:

  23. Explanation: Aspiration pneumonia occurs when food or liquid is breathed into the airways or lungs, instead of being swallowed. The major features of the lungs include the bronchi, the bronchioles and the alveoli. The alveoli are the microscopic blood vessel-lined sacks in which oxygen and carbon dioxide gas are exchanged. Source:

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