Dry Mouth or Xerostomia

Approved by the Cancer.Net Editorial Board, 05/2018

Dry mouth is also called xerostomia. It occurs when the salivary glands do not make enough saliva, or spit, to keep the mouth moist. Because saliva is needed for chewing, swallowing, tasting, and talking, these activities may be more difficult with a dry mouth.

Signs and symptoms of dry mouth

The signs and symptoms of dry mouth include:

  • A sticky, dry feeling in the mouth

  • Thick, stringy saliva

  • Pain or a burning sensation in the mouth or on the tongue

  • Cracks in the lips or at the corners of the mouth

  • A dry, tough tongue

  • Difficulty chewing, tasting, or swallowing

  • Difficulty talking

Dry mouth also often causes dental problems. Saliva helps maintain a healthy balance of bacteria in the mouth. Without enough saliva, the bacteria and other organisms in the mouth grow too quickly. This can cause sores and mouth infections, including thrush. Thrush is caused by an overgrowth of yeast.

Saliva also washes away food particles and acids left in the mouth after eating. This means that a lack of saliva can cause gum disease and cavities, also called tooth decay. Dry mouth may also make it difficult to wear dentures.

Causes of dry mouth

Chemotherapy and radiation therapy cause dry mouth by damaging the salivary glands. Chemotherapy causes dry mouth by making saliva thicker. But this is usually a temporary symptom that clears up about 2 to 8 weeks after treatment ends.

Radiation therapy to the head, face, or neck may also cause dry mouth. But it can take 6 months or longer for the salivary glands to start producing saliva again after radiation therapy ends. Some people notice dry mouth improving during the first year after radiation treatment. But many people continue experiencing some level of long-term dry mouth. This is especially likely if radiation therapy was directed at the salivary glands.

Dry mouth can also be caused by:

  • Graft-versus-host disease, in which cells transplanted from a donor recognize the patient's body as foreign and attack it

  • Antidepressants

  • Medicines called diuretics, which increase urination

  • Some painkillers

  • A mouth infection

  • Dehydration

Managing dry mouth

Relieving side effects is an important part of cancer care and treatment. This is called palliative care or supportive care. Talk with your health care team about any symptoms or change in symptoms you experience.

Dry mouth cannot be prevented, but some treatments can help. These include:

  • Medicines that prevent or lessen the side effects of radiation therapy, such as amifostine (Ethyol).

  • Saliva substitutes and mouth rinses with hyetellose, hyprolose, or carmellose.

  • Medicines that stimulate the salivary glands, such as pilocarpine (Salagen) or cevimeline (Evoxac).

  • Other ways to stimulate the salivary glands, such as sucking on sugar-free candy or chewing sugarless gum.

  • Acupuncture, which some research suggests can help with dry mouth.

The following tips may help you manage dry mouth and prevent dental problems:

  • Visit a dentist before starting radiation therapy or chemotherapy to check the health of your mouth and teeth. Schedule this as soon as you can. If you need to have teeth removed, it should be done at least 3 weeks before treatment so your mouth can heal.

  • Brush your teeth after each meal and at bedtime with a soft-bristle toothbrush and fluoride toothpaste. Soak the brush in warm water to make the bristles even softer.

  • Floss gently once a day.

  • Rinse your mouth 4 to 6 times a day, especially after meals, with salt and baking soda. Try a solution of half a teaspoon of salt and half a teaspoon of baking soda in 1 cup of warm water.

  • When radiation therapy starts, use fluoride rinses and gels. These are an important part of caring for the health of your mouth during cancer treatment.

  • Drink sips of water throughout the day, and use artificial saliva to moisten your mouth.

  • Avoid mouthwashes and other dental products that contain alcohol. Products designed for people with dry mouth are available without a prescription.

  • Use a cool mist humidifier, especially at night.

Some dentists may also prescribe medicines to increase saliva or rinses to treat infections in the mouth.

Consider the following tips for eating with a dry mouth:

  • Drink at least 8 cups of water a day. Carrying a bottle of water may help you drink enough.

  • Avoid alcohol, drinks with caffeine (such as coffee, tea, and soda), and acidic juices.

  • Eat soft, moist foods that are cool or at room temperature.

  • Moisten dry foods with broth, sauces, butter, or milk.

  • Avoid dry, coarse, or hard foods.

  • Avoid acidic or spicy foods that can burn your mouth.

  • Do not smoke or chew tobacco.

  • Avoid sticky, sugary foods and drinks.   

Related Resources

Cancer.Net Podcast: Managing Eating Challenges After Head and Neck Cancer Treatment

Dental and Oral Health

ASCO answers; Dental and Oral HealthDownload ASCO's free 1-page (front and back) fact sheet on Dental and Oral Health as a printable PDF.