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Mouth & Teeth

Xerostomia (dry mouth) and oral mucositis (redness and sores) are common side effects of cancer treatment.

Mouth and Teeth- Patient Handout

Xerostomia (dry mouth) is a change in the amount of saliva (spit) in your mouth. It is a common side effect of radiation therapy and medications. It is more common in older people.

Xerostomia may be a lifelong effect of treatment and medication. 

People with xerostomia should be very careful with acidic food and drinks. Acid can hurt your teeth. Drink water before brushing and after eating. Avoid drinking lemon water and other acidic drinks.‎


Oral mucositis is painful redness and sores in and around the mouth and throat. It can cause pain/discomfort and interfere with eating, swallowing and talking.


Oral mucositis is common for patients who are undergoing high-dose radiation for head and neck cancers and for patients who have had stem cell transplant therapy. Some patients who get chemotherapy will also notice oral mucositis as a side effect. Some chemotherapy drugs (such as, 5-FU, methotrexate, cycylopho-sphamide, etoposide and cisplatin) are known to cause oral mucositis.


Signs of oral mucositis are:

  • Pain in and around your mouth and throat
  • Sores (ulcers) in and around your mouth and throat
  • Sometimes the pain and sores are in the intestinal tract, causing pain, nausea, diarrhea and other infections

Symptoms may continue after treatment ends. 

Many patients do not report symptoms of oral mucositis to their doctors or dentists. If left untreated, it can lead to feelings of worry, depression and social isolation. It can also interrupt or delay cancer treatment. 

It is important for you to report symptoms of oral mucositis to your doctor or dentist.


Your dentist should work with you to treat any pre-existing dental problems (cavities, gum disease, infections, broken/sharp teeth, etc.) before your cancer treatment and make sure that your dentures are comfortable.

To help reduce your symptoms your doctor or dentist may order treatments such as drugs (to be taken by mouth or injected), a special oral rinse (mouthwash) or ice chips.

If you having difficulty eating and are losing weight ask to speak to a dietitian.

The most important thing you can do is start and maintain very good oral hygiene (regular brushing and flossing). Start oral hygiene two weeks before the start of cancer treatment or as early as possible.



  • If flossing is part of your usual routine, continue to floss once per day, at bedtime, before brushing
  • If flossing is not part of your usual routine, do not start flossing (unless recommended by your dentist)
  • Stop flossing if it causes pain or bleeding gums that does not stop after 2 minutes

Oral rinses

  • Oral rinses help keep mouth moist and clean 
  • Rinse your mouth often (about four times each day), after brushing
  • Use 1 tablespoon (15ml) of oral rinse, swish in your mouth for 30 seconds, then spit it out (if you are using a homemade oral rinse, make it daily to avoid risk of germs)

Recipes for bland oral rinses

  • Recipe # 1: Mix ½ teaspoon (2.5 ml) of salt in 8 oz (240 ml) of water
  • Recipe # 2: Mix ¼ to ½ teaspoon (1.25-2.5 ml) baking soda in 8 oz (240 ml) of water

Other things you can do for yourself

  • Make sure that your health care team (your family, nurse, doctor, dentist, radiation therapist and other specialists) knows about your symptoms and what you are doing to manage them
  • Use water or aloe based lubricant to protect and moisten lips  Leave dentures out of your mouth during sleep and as much as possible during cancer therapy
  • Drink lots of liquids (8-12 glasses each day)
  • Eat bland, soft foods while maintaining adequate protein and vitamin levels
  • Rinse your mouth with water after eating or drinking
  • Avoid alcohol based mouthwashes mouthwashes
  • Avoid spicy, acidic or coarse foods
  • Avoid alcohol
  • Avoid smoking
  • Avoid biting trauma
  • Avoid teeth grinding or clenching

You may also want to ask your doctor or dentist about a prescription for an oral rinse (mouthwash) that can help. Mouthwashes for oral mucositis are made up of different drugs. These mouthwashes have to be compounded at a pharmacy. They can be expensive and they are not typically covered by Pharmacare. If you are registered with Pharmacare the Pharmacist can ask for special authority from Pharmacare to have some of the costs covered.

Information for patients

Recommended websites: Mouth and Teeth Websites


Symptom management guidelines: Oral MucositisXerostomia


For more suggestions about eating with a dry or sore mouth please see our nutrition handouts section


Information for health professionals

Magic Mouthwash Explained (Excerpted article from the Fall 2014 edition of the Journal of Family Practice Oncology). 

*Thank you to the BC Cancer Family Practice Oncology Network, Dr. A. Hovan, Dr. H. Pada and Dr. B. Chan


Revised: December 2016

SOURCE: Mouth & Teeth ( )
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