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Dry mouth

Dry mouth is also called xerostomia. It refers to a lowering of the quality and amount of saliva. Saliva helps break down food and start the digestion process. It also helps prevent mouth infections and tooth decay by lowering acid levels in the mouth and cleaning the teeth and gums. If there isn’t enough saliva, the mouth cannot clean itself properly and the teeth can lose minerals.

Dry mouth can also cause difficulty chewing, swallowing and talking. Severe dry mouth can interfere with your ability to maintain good nutrition.


Dry mouth can have different causes. Radiation to the head, neck or mouth area is the most common cause of dry mouth in people with cancer. Radiation can affect the salivary glands so they don’t make as much saliva or it doesn’t flow properly. This can result in a dry mouth.

Dry mouth can also be caused by:

  • surgery that removes the salivary glands (such as for salivary gland or oral cancer)
  • certain drugs such as antihistamines (allergy medicines), antidepressants, diuretics or opioids
  • side effects of a bone marrow or stem cell transplant such as graft-versus-host disease


Symptoms of dry mouth can vary depending on its cause and other factors. Symptoms may include:

  • sticky, dry feeling in the mouth or throat
  • thick, stringy saliva
  • burning feeling in the mouth
  • dry, cracked lips and tongue
  • increased thirst
  • changes in taste
  • difficulty chewing, tasting or swallowing
  • speech difficulties
  • problems with dentures
  • mouth sores or infections
  • tooth decay

Dry mouth can develop differently depending on the cause. Radiation therapy to the head and neck can cause temporary or long-term dry mouth. Dry mouth usually develops during the first 2–3 weeks of radiation therapy. In many cases, excessive salivation and drooling develops before dry mouth. These symptoms suddenly stop and dry mouth occurs. Dry mouth from radiation therapy can become worse over time. The salivary glands may partially recover within the first year after radiation therapy. They rarely recover completely or return to normal after radiation therapy.

Chemotherapy can make saliva thick, which causes the feeling of dry mouth. Dry mouth from chemotherapy is usually temporary. Saliva usually returns to normal 2–8 weeks after treatment ends.

Surgery that removes the salivary glands will cause an immediate, permanent dry mouth.

Managing dry mouth

Once the extent and cause of dry mouth is known, your healthcare team can suggest ways to help manage it. You can also try the following to help manage dry mouth.


Dry mouth can make it difficult to swallow and eat. Try the following measures to help you maintain good nutrition if you have dry mouth.

To help keep your mouth moist, sip water, juices and other fluids frequently throughout the day. Carry a water bottle, so it is easy for you to sip water frequently. You can also suck on ice chips, sugarless hard candy, or popsicles or chew sugarless gum to stimulate the salivary glands. Avoid juices and liquids with a lot of sugar or that are acidic because they can contribute to tooth decay. Limit drinks with caffeine such as coffee, tea and some soft drinks. Caffeine can dry out the mouth. Rinse the mouth with water throughout the day and before eating.

Sip water or a sugarless drink during meals and take sips of fluid between bites of food. This will make chewing and swallowing easier. Eat soft foods that are cool or at room temperature. It may help to blend foods into a puree. Use butter, margarine, cream, milk, broth, soup, gravy or sauces to help moisten foods and make them easier to chew and swallow. Make gravy and have it ready to add to meat, potatoes and vegetables. Dunk or soak dry foods in liquids. Avoid foods like muffins, crackers and rice that break down into little pieces in the mouth.

Add ice or skim milk to commercial nutritional supplements or milkshakes if they tend to coat the mouth or are difficult to swallow.

Limit salty, acidic or spicy foods. Avoid alcohol and tobacco.

Oral hygiene

It is important to maintain good nutrition and mouth care if you have a dry mouth. To avoid mouth problems such as cavities, clean your mouth and teeth at least 4 times each day. Use a soft-bristle toothbrush and rinse the toothbrush in hot water to soften the bristles. Brush the tongue gently. Your healthcare team may recommend a fluoride toothpaste, rinse or gel.

After meals and before bed, rinse your mouth with a solution of salt or baking soda and water. Different cancer treatment centres may recommend different amounts of salt or baking soda, so check with your healthcare team. A combination of salt and baking soda may also be used. Baking soda may help to thin saliva and lower the acid effect of dry mouth, but lower acid levels may also promote bacteria growth. Do not use mouthwashes that contain alcohol. These dry the mouth even more. Avoid lemon glycerine swabs, which also dry the mouth.

Your healthcare team may recommend products to moisten the mouth such as a saliva substitute, or artificial saliva. Artificial saliva products can include mouth rinses, sprays or gels. Your healthcare team may also prescribe a medicine called pilocarpine (Salagen), which stimulates the salivary glands to make saliva.

Keep lips moist with a water-based lip balm. Ask your healthcare team which types of lip balms or moisturizers are good to use.

Have regular dental checkups and talk to the dentist about other ways to help care for the teeth, mouth and gums and prevent tooth decay. See a dentist at least 2 weeks before treatment starts for an assessment of the mouth and teeth and to get any dental work done before dry mouth becomes a problem.

A room humidifier may help relieve dryness. Acupuncture may help increase salivary flow. Check with the healthcare team to see if this is an option.


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