Mouth problems

Dry mouth

Radiation therapy to the head or neck area can cause dry mouth (xerostomia). This can make chewing and swallowing difficult. A dry mouth can also make it harder to keep your teeth and mouth clean, which can increase the risk of developing cavities.

Managing dry mouth

  • Ask your dentist about an oral care plan and have regular check-ups.
  • Carry a water bottle and have regular sips throughout the day.
  • Limit alcohol and caffeinated drinks as these are dehydrating, and avoid smoking.
  • Add moisture to meals with extra sauce or gravy.
  • Chew sugar-free gum to stimulate the flow of saliva.
  • Soften food by dipping it into milk or soup, or moisten it with gravy, sauce, cream or custard.
  • Drink milk with meals to help soften the food and make it easier to swallow.
  • Try acupuncture as this may help increase saliva.
  • Use lubricating agents or dry mouth gels available from the chemist. Swirl olive oil in your mouth and then spit out.

Mouth sores and ulcers

During chemotherapy and radiation therapy, mouth sores are common. The sores can form on any soft tissue in your mouth, making eating, swallowing and talking difficult.

Your doctor can give you medicines to reduce the pain when you eat, drink or speak. Some pain relief medicines can be applied directly to the mouth sores to numb them. Your dietitian can suggest foods to reduce discomfort. You may need to choose softer foods and nourishing fluids. If you are unable to eat and drink enough to meet your nutritional needs, you may need a feeding tube to support you during recovery.

Managing mouth sores and ulcers

  • Talk to your doctor about mouthwashes or medicines to relieve ulcers and to keep your mouth fresh.
  • Use a soft-bristled toothbrush and replace it often to reduce infections. Brush gently.
  • Suck on ice cubes.
  • Avoid rough, crunchy or dry foods (e.g. chips, nuts, toast, crackers). Also avoid vinegar, spices, salty foods, alcohol, very hot or very cold foods and drinks, citrus or tomato-based food and juice.
  • Gargle with ½ tsp salt plus ½ tsp baking soda in a glass of warm water. Use frequently as a mouthwash.
  • Tell your doctor or dietitian if you have ongoing or severe difficulty swallowing.
  • Download the Mouth Health and Cancer Treatment fact sheet from this page.

Difficulty kissing

Surgery to the mouth may reduce sensation in the tongue or lips. This can affect the enjoyment and stimulation from kissing, but sensation should return in 12–18 months.

Side effects such as dry mouth, bad breath due to changes in oral bacteria, poor tongue and lip movement, scars, or a stiff neck and jaw can also make kissing difficult or less pleasant.

Some people choose to express their feelings in other ways, such as hugging, holding hands or touching cheek-to-cheek. However, if you or your partner are distressed by these changes, it may help to talk to a counsellor.


This information was last reviewed in May 2017
View who reviewed this content
View our editorial policy

Support services

Life after cancer treatment
Webinars, exercise and nutrition, sexuality programs, and back-to-work support

Need legal and financial assistance?
Pro bono services, financial and legal assistance, and no interest loans

Coping with cancer?
Talk with a health professional or someone who has been there, or find a support group or forum

Cancer information

Nutrition after cancer treatment
Healthy eating habits to help you maintain good nutrition 

Nutrition and cancer help for carers
Tips for preparing food for someone with cancer

View our publications
Guides and fact sheets for people with cancer, their families and friends

TOP BACK TO TOP