Dry Mouth or Xerostomia

Approved by the Cancer.Net Editorial Board, 10/2020

Dry mouth is also called "xerostomia." It happens when the body's salivary glands do not make enough saliva, or spit, to keep the mouth moist. Saliva is needed for chewing, swallowing, tasting, and talking. A dry mouth can make these activities difficult or uncomfortable.

What are the 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 corner of the mouth

  • A dry, tough tongue

  • Difficulty chewing, tasting, or swallowing

  • Difficulty talking

Saliva helps keep the balance of bacteria in your mouth healthy. Without enough saliva, bacteria and other organisms in the mouth grow too quickly. This imbalance can cause mouth sores and mouth infections, including thrush. Thrush is caused by an overgrowth of yeast.

Dry mouth often causes dental problems. Saliva also washes away food particles and acids left in the mouth after eating. This build up of food particles and acids can cause gum disease and cavities, also called tooth decay. Dry mouth may also make it difficult to wear dentures.

What causes dry mouth? (updated 07/2021)

Radiation therapy and chemotherapy may cause dry mouth by damaging salivary glands.

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

There are some ways to reduce or prevent damage to the salivary glands when radiation therapy is used. ASCO recommends using methods of radiation therapy, such as intensity-modulated radiation therapy (IMRT), that limit the amount of radiation to which the salivary glands are exposed. During radiation therapy, acupuncture or bethanechol (Duvoid, Urecholine) may be recommended. Bethanechol is a medication that stimulates the production of saliva.

Chemotherapy may also cause dry mouth, but it is usually temporary. It usually clears up 2 to 8 weeks after the treatment ends.

Dry mouth can also be caused by:

  • Graft-versus-host disease, a possible side effect of bone marrow/stem cell transplantation

  • Antidepressants

  • Medicines called diuretics, which increase urination

  • Some pain medications

  • Medications that prevent nausea and vomiting, called antiemetics

  • A mouth infection

  • Dehydration

How can dry mouth be managed? (updated 07/2021)

Relieving side effects is an important part of your 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, including dry mouth. And, let them know regularly how you are feeling or about side effects you are experiencing, so that they can find ways to help you feel better.

Supportive care that can help with dry mouth includes:

  • Saliva substitutes and mouth rinses.

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

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

  • Acupuncture after radiation therapy in people with head and neck cancer.

  • Transcutaneous electrical nerve stimulation (TENS) of the salivary glands after radiation therapy in people with head and neck cancer. During TENS, a low-voltage electric current is run through electrodes placed on the skin.

This information is based on the joint ISOO/MASCC/ASCO guideline “Salivary Gland Hypofunction and/or Xerostomia Induced by Non-Surgical Cancer Therapies.” Please note that this link takes you to another ASCO website.

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

Visit a dentist. Before you begin radiation therapy or chemotherapy, the health of your mouth, including teeth, gums, oral mucosa (lining tissues of the mouth), and salivary glands should be evaluated by a dentist. Schedule this appointment as soon as you can. If you need to have teeth removed, it should be done as soon as possible so your mouth can heal before cancer treatment. Dentists may instruct you how to stimulate saliva secretion and lubricate your mouth or prescribe medication to increase saliva or rinses to treat infections in the mouth during your treatment period.

Maintain good dental health. Brush your teeth after each meal and at bedtime. Use 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. Rinse your mouth 4 to 6 times a day, especially after meals, with water, salt and baking soda. Try a solution of 1 teaspoon of salt and 1 teaspoon of baking soda in 1 gallon 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.

Stay hydrated. Drink sips of water throughout the day, and use saliva substitutes to moisten your mouth. Always keep water nearby in a water bottle to help you drink enough.

Avoid dental products that contain alcohol. Mouthwashes and other dental products often contain alcohol. This can make dry mouth worse. Alcohol-free mouthwashes and other products made for people with dry mouth are available without a prescription.

Use a cool mist humidifier. Keep it running at night, especially during the winter.

Maintain good nutrition. If you're having trouble eating or drinking because of your dry mouth, consider the following tips:

  • Avoid alcohol, drinks with caffeine (like 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.

Questions to ask your health care team

Consider asking your health care team these questions about dry mouth.

  • Could my cancer treatment cause dry mouth? If so, when could dry mouth start?

  • Is there a way prevent dry mouth?

  • Should I see a dentist before my cancer treatment starts?

  • Who should I tell if I start experiencing dry mouth?

  • Are there rinses or medicines that can help relieve my dry mouth?

  • Are there other things I can do at home to help relieve my dry mouth?

  • What are the signs of a mouth infection that I should watch for?

  • What are signs that dry mouth is affecting my hydration or nutrition?

  • Should I keep track of my dry mouth? If so, how should I track my symptoms?

Related Resources

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

Dental and Oral Health

Long-Term Side Effects of Cancer Treatment

More Information

U. S. National Library of Medicine: Dry Mouth During Cancer Treatment