Dry Mouth After Radiation Therapy: Why It Happens

Tips to Avoid Dry Mouth During Radiation Therapy

elderly woman drinking water from glass
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Xerostomia, also known as dry mouth, is the result of the salivary glands not producing enough saliva to keep the mouth moist. Common cancer treatments such as radiation therapy can cause symptoms of dry mouth among many other uncomfortable side effects.

Dry Mouth as a Cancer Treatment Side Effect

Radiation therapy to the head and neck can harm the salivary glands, which can lead to dry mouth. Chemotherapy can also cause harm to the mouth, throat, and lips.

The signs or symptoms of dry mouth include:

  • A dry, sticky feeling in the mouth
  • Saliva that is thick or stringy
  • A burning, painful sensation in the mouth or tongue
  • Difficulty chewing, tasting, or swallowing
  • Difficulty talking

In addition to overall discomfort, dry mouth problems can interfere with dental health and with eating and drinking, which can lead to dehydration or malnutrition. Fortunately, most people eventually regain salivary gland function weeks (or sometimes months) after treatment is over.

Before Beginning Radiation Treatment

Before starting your cancer treatment, make sure you visit your dentist for a thorough cleaning and check-up. Let your dentist know about your cancer treatment and get all dental work completed before treatment begins.

Make sure that you check your mouth every day for sores or white spots. If you notice any pain or sensitivity, let your doctor or nurse know. During the day, make sure to rinse your mouth with a solution of warm water, baking soda, and salt.

Gently brush your teeth, gums, and tongue after eating and before going to bed. Use a very soft toothbrush or cotton swabs to clean your teeth.

How to Deal With Symptoms During Treatment

There are several things you can do to remedy the symptoms of dry mouth during radiation therapy:

  • Stay well hydrated by carrying a water with you at all times and sipping on water frequently.
  • Choose to eat foods that are soft and easy to swallow.
  • Make milkshakes or blend food to make it easier to swallow.
  • Chewing sugarless gum (sugar can increase the risk of cavities, especially when you have less saliva) to help keep the inside of your mouth moist and increase the production of saliva.
  • Use numbing sprays before you eat to make eating less painful.
  • Avoid foods that are crunchy, salty, spicy, or sugary.
  • Avoid caffeine and alcohol as they can act as a diuretic (promotes the production of urine) leading to dehydration.
  • Don’t smoke or use tobacco products.
  • If you have a change in your sense of taste, try cold foods or iced smoothies to make the food more palatable for you.
  • Try sipping through a straw if drinking liquids from a cup becomes difficult.
  • Try using a humidifier in your home or bedroom. 

Your dentist may want you to maintain regular visits during your radiation therapy treatments in order to check your teeth and your mouth and to help you deal with any oral problems.

Your doctor may also recommend over the counter (OTC) products such as mouthwashes, toothpastes and sprays to help with saliva production and add moisture to the mouth. There are also prescription medications that can help increase saliva production and reduce dry mouth, such as pilocarpine (Salagen) or cevimeline (Evoxac).


The Oral Cancer Foundation. Xerostomia.

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