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What is Sialorrhea?

C. Martin
C. Martin

In human biology, sialorrhea is a medical condition characterized by drooling, or excessive salivation. The drooling may be caused by the production of too much saliva or by a decreased ability to swallow, or by a combination of these two factors. There are a number of other terms by which sialorrhea is also known, including ptyalism, hyperactive salivary flow, polysialia, and sialism.

Saliva is produced in the mouth from three major salivary glands, the parotid gland, the submandibular gland, and the sublingual gland, as well as from a number of smaller glands. The amount of saliva that is produced is affected by several different factors, and when much more saliva is produced than is required, drooling may result. It is particularly noticeable when the excess saliva production is accompanied by impaired swallowing.

A decreased ability to swallow may cause sialorrhea.
A decreased ability to swallow may cause sialorrhea.

Sialorrhea causes can be varied. It can be a symptom of one of a number of neurological disorders, such as cerebral palsy and Parkinson’s disease. Sialorrhea diagnosis can also be linked with infection or poisoning. Heavy metal poisoning in particular, such as mercury poisoning, tends to induce drooling. Poisoning with insecticides and nerve gases is also known to have a similar effect.

Nerve gas poisoning may cause sialorrhea.
Nerve gas poisoning may cause sialorrhea.

A number of medicinal drugs are known to have induced sialorrhea as a side effect. The most commonly reported of these are antipsychotic drugs, in particular a drug called clozapine. Some of the drugs that are used to treat Alzheimer’s disease and related disorders are also often associated with drooling.

Treatment for sialorrhea usually depends on the root cause. If it is a side effect induced by prescribed drugs, then treatment is often limited to managing the excess salivation to a point where it can be controlled without too much impact on the patient. While drooling is often considered a cosmetic problem for patients, it can lead to hygiene problems, dehydration, and skin problems around the mouth. In some cases, drooling can also significantly hinder the ability of the patient to successfully engage with speech therapy where required, for example in some neurological disorders.

Sialorrhea may occur as a side effect of certain medications.
Sialorrhea may occur as a side effect of certain medications.

There are certain drugs that may be used in sialorrhea treatment. These drugs largely work by affecting the nervous system to reduce salivation, but they often have significant side effects. In extreme cases, where drooling is a long-term problem, surgical treatment of sialorrhea has been used, in the form of removal of one or more of the major salivary glands.

Discussion Comments


Is sialorrhea always a symptom of something else or could it just be caused by normal fluctuations in the body?

I find that during allergy season I suffer from excessive saliva buildup and it is really uncomfortable and makes it hard to get through the day. It is even worse when I try to sleep at night because I find I make a bit of a mess on my pillow.

Do you think this could have something to do with my medication I take for allergies, or more a result of the allergies themselves? I have also considered that it may just be a sign that I am feeling anxious about my allergies.


My friend suffered from sialorrhea while he was taking clozapine for his bipolar disorder. Sialorrhea for him was mild, but still embarrassing and he ended up needing to switch drugs so that he wouldn't have to worry about getting through his day with too much saliva.

He found the most difficult thing with sialorrhea was sleeping, as the saliva would make it difficult to keep his pillows clean. For the most part he just covered everything he came in contact with. He mostly used clean towels and switched them daily.

Luckily, once he switched drugs his symptoms of sialorrhea went away.

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    • A decreased ability to swallow may cause sialorrhea.
      By: Andriy Petrenko
      A decreased ability to swallow may cause sialorrhea.
    • Nerve gas poisoning may cause sialorrhea.
      By: Fernando Cortés
      Nerve gas poisoning may cause sialorrhea.
    • Sialorrhea may occur as a side effect of certain medications.
      By: milosducati
      Sialorrhea may occur as a side effect of certain medications.