What Causes Dry Mouth?

There are a variety of dry mouth causes, which we will outline in this article. In general, the condition is caused by either insufficient saliva being produced or it being cleared away too quickly.

It is important to note that although many people get the problem as they get older, it is not a normal sign of ageing. Instead, if we get it in our old age it is generally due to other factors such as prescription medicines. So don’t ignore the problem and put it down to ‘getting old’.

Here are the main causes to be aware of:


Prescription medicines

Prescribed medications can have a range of side effects, and for several this includes causing dry mouth (also known as ‘xerostomia’). Some drugs that commonly lead to the problem include:

A wide range of prescription medicines can cause dry mouth

  • Antidepressants, used to treat depression and anxiety
  • Amphetamines
  • Antihistamines and decongestants, used for example in those with hay fever. Can be prescribed or bought over-the-counter.
  • Diuretics and beta-blockers, commonly used to manage heart disease and high blood pressure.

There are many other medicine that produce xerostomia as a side effect, for example antipsychotic drugs, medicines to control Parkinson’s disease and some anti-epileptic medications. If you have any concerns about drug-induced xerostomia then consult your doctor.


Medical Conditions And Treatments

There are several diseases that can lead to this condition. Some of the main xerostomia causes are:

  • Sjögren’s syndrome. This is an ‘auto-immune’ disease that can affect the joints, eyes and mouth.
  • Diabetes that is poorly-controlled
  • Alzheimer’s disease
  • Rheumatoid arthritis
  • HIV
  • The salivary glands can be damaged as a result of chemotherapy and/or radiotherapy
  • Dehydration can lead to dry mouth, as fluids are preserved for more important areas of the body.

Physical damage or disease to the salivary glands (that produced saliva) , their ducts (that channel the saliva into the oral cavity) or the nerves that supply the glands can all lead to not enough saliva being produced and/or secreted.


Other Causes of Dry Mouth

Aside from the above-listed medical causes, there are several other common factors to be aware of:

  • Drug abuse. Methamphetamine, cannabis and heroin can lead to xerostomia. Methamphetamine abuse can lead to ‘meth-mouth’, where the teeth can develop cavities very rapidly.
  • Alcohol – As a diuretic, alcohol leads to excess loss of bodily fluids.
  • Smoking, another common dry mouth cause.
  • Anxiety is known as another factor that frequently results in the problem.
  • Caffeine, found in coffee and many soda drinks.
  • Pregnancy – Many women complain of this when expecting -it is often worse at night.


As mentioned above, the problem is caused by insufficient saliva being produced or the saliva being cleared away too quickly. All of the above causes are down to the former. The latter cause of xerostomia is found in people who breath excessively through their mouths (‘mouth-breathing’). This can be as a result of nose-blockage. Some people also breath only through their mouths while sleeping, leading to night-time xerostomia.



There are many different factors that can cause dry mouth. If you suffer from the problem, finding out the cause is the first step in getting treatment.

Next, red our page on xerostomia treatment or return to the main page on the condition.

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