Decorative image

Mouth and teeth after head and neck radiotherapy

You might have problems with your mouth or teeth during or after radiotherapy to your head and neck.

Having a sore mouth

The cells lining your mouth are sensitive to radiation. So after a few days, radiotherapy to your mouth is likely to make it sore. This is called oral mucositis.

The soreness usually only lasts while you are having treatment and for a few weeks afterwards. 

Eating and drinking

While your mouth is sore you may find that some foods or drinks are too strong for you to cope with. These include highly flavoured or spiced foods, and strong alcohol. It is best to avoid these while having treatment.

You may have to eat a bland or soft diet for a while. Dry foods can hurt and scratch your mouth. You may also find that hot foods or drinks make your mouth more sore. Try eating your food when it is just warm.

Mouth care

A dry, sore mouth is more prone to infection. So your doctor or nurse might give you mouthwashes and a mouth care routine to follow. This helps keep your mouth healthy during your treatment. 

It is important to keep your mouth clean and as healthy as possible. It's best to use a small soft toothbrush to clean your teeth. And you might need to clean them more than twice a day.


Smoking might make the soreness worse. You can try to cut down on smoking. Or you could talk to the radiotherapy staff about nicotine replacement treatments.

Mouth ulceration

Sometimes the delicate lining inside your mouth can break down during radiotherapy. This is called ulceration. If it happens, the radiotherapy staff give you painkillers to help you cope with it. 

You might need to have a fine feeding tube into your nose if your mouth is very sore, because it will be painful to eat or drink. The tube is called a nasogastric tube.

Or you might have a tube put directly into the stomach through the skin and muscle of the abdomen. The tube is called a percutaneous endoscopic gastrostomy tube (PEG tube).


If you wear dentures they may make your mouth more sore during radiotherapy treatment. You might find it more comfortable to take them out for some periods during the day.

Dry mouth

Your treatment might affect the salivary glands so that they produce less, or no, saliva. It can be uncomfortable to chew or swallow. In the early days of the treatment your saliva might become very thick and difficult to swallow.

After the treatment ends it can take a long time (6 months or more) for saliva production to get back to normal. If the radiotherapy treatment area included the salivary glands, you might have a permanently dry mouth afterwards.

If you have a severely dry mouth, talk to your radiotherapy doctor (clinical oncologist) or radiographer.

Some of the following tips may help:

  • Clean your tongue with a liquid made from a teaspoonful of bicarbonate of soda in a litre of warm water.
  • Use moistened cotton wool or a soft toothbrush to clean your tongue.
  • Sip drinks often to keep your mouth moist.
  • Fizzy drinks can refresh your mouth.
  • Moisten your food with sauces, gravy, cream, custard or ice cream.
  • Chewing gum can make your salivary glands produce more saliva.
  • Get your doctor to prescribe boiled sweets that boost saliva production, lozenges, and artificial saliva sprays or gels.
  • Ask your doctor to prescribe medicines that stimulate saliva.
  • Don't eat chocolate and pastry, because they tend to make your mouth more dry.
  • Use lip balm to keep your lips moisturised.
  • Moisten the inside of your mouth at night with a small amount of olive oil.

Thrush infection

The treatment might also make it easier for infections of the mouth to develop, such as thrush. 

Let your doctor or nurse know if you have any white patches on the inside of your mouth or on your tongue. They can prescribe medicines to help.

Your radiotherapy staff will check your mouth regularly during your treatment.

Taste changes

Your taste buds might also be affected by radiotherapy to the head or neck area. You might notice changes in the way your food tastes. Some people say their food has a metallic taste. Others say that all foods taste the same.

There are some tips on making food more tasty. You might need to wait to try these until your mouth has recovered from the treatment and is not sore any more.

You could try using more herbs and spices to flavour your food, as well as using strong tasting sauces like sweet and sour. Sharp tasting foods, such as fresh fruit and sharp boiled sweets can be refreshing but only use these after your mouth has healed. A glass of sherry before a meal can make food taste better.

The radiotherapy staff can arrange for you to talk to a hospital dietitian for advice about overcoming taste changes.

Problems with your teeth

Radiotherapy to your mouth can make you more likely to get tooth decay afterwards. You'll need to go for check ups at the dentist more often. Fluoride treatment might help to protect your teeth. You can have this as a mouthwash to use twice a day. 

You might need to have some teeth taken out before you start treatment. Before radiotherapy to your mouth, face, or neck your radiotherapy doctor might refer you for a dental examination.

Remember to tell your dentist that you have had radiotherapy to your mouth before you have any dental work. Your dentist might need to change the way they treat you. They may also need to talk to your radiotherapy doctor before giving you any treatment.

Information and help

Dangoor sponsorship

About Cancer generously supported by Dangoor Education since 2010.