Mouth care during radiotherapy - coping with a dry mouth (xerostomia)
Radiotherapy to the head and neck can cause the glands in the mouth to produce less saliva and make your mouth dry. This is called xerostomia and it can be temporary or permanent.
This information is about how you can help yourself if you are having problems with a dry mouth. You may also find it helpful to read our information about radiotherapy and diet.
Saliva, or spit, is the fluid produced by the salivary glands, which are situated around the jaw and under the tongue. Saliva keeps the mouth clean and helps prevent infection. It also protects your teeth, as a lack of saliva can increase your risk of developing tooth decay or gum disease.
When you eat, more saliva is produced to moisten the food, which makes it easier to chew and swallow. The saliva also begins the process of digestion. A lack of saliva can change the taste of the food you eat and may also mean that you cannot swallow food so well.
Radiotherapy treatment to the head and neck, or mouth, can affect the salivary glands, so that less saliva is produced. The glands may recover over time (sometimes this takes several months), but for some people the dry mouth may be permanent.
How your doctor can help
Back to top
Drugs to stimulate saliva
It's important to tell your doctor if you have a dry mouth, as they may be able to prescribe medicines to help. Pilocarpine (Salagen®) is usually used. Sometimes a drug called bethanechol (Myotonine®) may be used instead of pilocarpine, although it's not licensed to treat dry mouth.
These drugs stimulate the salivary glands to produce saliva and will only work if the damage to the glands is temporary or partial. Two or three months of continuous treatment with pilocarpine may be needed before it is effective in stimulating temporarily damaged salivary glands to work again.
Like many drugs, pilocarpine and bethanechol have side effects, which can include dizziness, sweats, feeling sick (nausea) and being sick (vomiting).
Artificial saliva products can also help moisten the mouth. As their effect may last only for a short time, it's best to use them just before meals and at night to prevent the dryness from disturbing your sleep. Some artificial saliva products are acidic and can damage your teeth, so try to use a saliva substitute that is pH neutral.
Several brands are available and they come in the form of a gel, spray, pastille or tablet. You may find it helpful to try more than one form of artificial saliva brand to find out which one suits you best.
How you can help yourself
Back to top
Keep your mouth clean
As saliva helps keep your mouth clean, it is important to brush your teeth with a soft toothbrush twice a day and to use mouthwashes regularly. Mouthwashes containing detergents or alcohol should be avoided as they can dry and irritate the lining of the mouth. Your doctor or nurse will be able to advise you about the best mouthwash to use.
Visit your dentist
Regular dental check-ups are essential, as the risk of developing tooth decay is increased by a lack of saliva.
Encourage saliva production
If your salivary glands are still able to produce some saliva, sucking sugar-free sweets or chewing sugar-free gum can encourage saliva production. Pineapple chunks, ice cubes, frozen tonic water, yoghurt and buttermilk can also be helpful, although some people find that very cold foods or drinks may be too uncomfortable to use.
Keep your mouth moist
To keep your mouth moist you can drink sips of water or sugar-free fizzy drinks regularly throughout the day. Rinsing your mouth with a little vegetable oil (about a teaspoonful - 5ml) or a small amount of softened butter or spread (margarine) can also help, especially at night.
Cut down or avoid substances that can dry the mouth
These include alcohol, caffeine and cigarettes. Some prescribed medicines can also cause a dry mouth - it can be helpful to ask your doctor or nurse to identify these, as it may be possible to reduce the dosage or change the drug. It may also be helpful to try acupuncture as this may sometimes increase the amount of saliva that is produced.
Many people can lose their appetite because of a dry mouth, or may find that foods taste different, which can cause eating difficulties. Here are some tips that can make food more palatable:
Make sure you drink fluid with meals.
Include plenty of sauces and gravy with meals.
Include foods with a high fluid content in your diet, such as jelly, puréed fruits and soft puddings.
Avoid dry and 'thick' foods such as biscuits, crackers and dry snacks.
This section has been compiled using information from a number of reliable sources including:
Souhami Hochhaser. Cancer and Its Management, 6th edition. 2010. Wiley-Blackwell.
Doyle et al. Oxford Textbook of Palliative Medicine 3rd edition. 2005. Oxford University Press.