Mouth care and cancer

Looking after your mouth is important when you have cancer. You can get useful tips on how to cope with common mouth problems.

It's important to keep your mouth very clean and moist:

  • during cancer treatment
  • if you're not eating and drinking normally
  • if you're at risk of infections

General mouth care

  • Let your doctor or specialist nurse know if your mouth is getting sore - they can prescribe medicines to help.

  • Clean your mouth and teeth gently every morning, evening and after each meal.

  • Use a soft bristled or child's toothbrush.

  • Use alcohol free mouthwash instead if your toothpaste stings or if brushing your teeth makes you feel sick.

  • You can use dental floss gently every day (if your doctor agrees) but be careful not to harm your gums.

  • Your doctor or specialist nurse can prescribe mouthwashes containing local anaesthetic if your mouth is very sore.

  • Clean your dentures every morning, evening and after each meal.

  • Use lip balm to keep your lips moist.

  • Moisten your mouth at least every 2 hours with mouthwash or a foam if you're not eating or drinking normally.

  • Salt water or bicarbonate of soda rinses can help to keep your mouth clean.

Remember to tell your doctor or nurse straight away if you start to get any mouth problems.

Support from your doctor, nurse or dentist

When you have radiotherapy to your mouth, you may need to see your dentist for a check up. This is usually at least 2 weeks before treatment begins.

Your dentist will check for any tooth decay or gum problems. They’ll treat these before you begin your radiotherapy.

Your doctor or specialist nurse might give you one or more alcohol free mouthwashes to use every 4 hours while you're having treatment. This is to help stop infection.

You might have anti fungal lozenges, drops or mouthwashes too. It’s important that you try to remember to use these as prescribed.

Your doctor might give you a mouthwash that contains local anaesthetic if you have a very sore mouth. You use it several times a day. Ask your doctor about this if you think it might help you.

You can also have painkillers. Some people have morphine drips (infusions) because their mouths are so sore. So do tell your doctor or nurse if your mouth is painful.


Dentists recommend flossing to keep your mouth fresh and clean. But it can damage the gums.

This matters because blood cells called platelets are important for blood clotting. But people having chemotherapy can have a low platelet count. This is common with the high dose courses of chemotherapy for leukaemia or lymphoma.

Your doctor might not want you to use dental floss if you have a low platelet count because it can make your gums bleed. Check with your doctor or specialist nurse first.

There are alternatives, such as inter dental toothpicks or gum stimulators (rubber tips). But be careful with these too. Sticking anything in between your teeth can cause gum damage. Infection can get in if your gums are bleeding.

Tips for coping with problems

Some cancer drugs, painkillers and radiotherapy can make your mouth dry. After radiotherapy to the head, some people can have a permanently dry mouth.

Your mouth may also be dry if you’re not eating or drinking properly because you’re not well enough.

Tips to help you cope
  • Choose meals that are moist.

  • Use gravies and sauces to make swallowing easier.

  • Take regular sips of water with your meal to help you chew and swallow your food. Try to drink plenty of water throughout the day.

  • Milk, water, fruit or vegetable juices are the best drinks to choose, but any fluid is better than nothing.

  • Dilute citrus juices with water so they’re not as acidic.

  • Suck ice to keep your mouth refreshed.

  • Chew sugar free chewing gum.

  • Eating fresh pineapple can keep your mouth fresh and moist but avoid acidic fruits (such as oranges, grapefruit) if your mouth is sore.

  • Ask your doctor about medicines to stimulate your salivary glands or artificial saliva products. They can suggest what might help in your situation.

  • Talk to your doctor or nurse about the medicines you are taking if there’s no obvious reason for your dry mouth.

Some chemotherapy drugs can make food and drink taste strange to you.

Radiotherapy to the mouth may permanently change your sense of taste. This may improve slowly over time.

Any treatment that has affected your sense of smell will also affect your sense of taste. This is because the scent of food contributes a great deal to how it tastes. 

Tips to help you cope
  • Avoid foods that taste strange to you but try them again every few weeks because your taste could have gone back to normal.
  • Choose foods that have strong flavours such as herbs, spices and marinades if all your food tastes the same.
  • Try adding garlic, lemon juice, herbs and spices to food.
  • You can marinate foods overnight or even 10 minutes will make a difference.
  • Make a marinade with a couple of tablespoons of olive oil add herbs or spices and a splash of wine or some lemon juice if you like.
  • You can use a dry marinade which is sometimes called a rub. Mix up spices and herbs and rub onto uncooked meat or fish with clean hands.
  • Be careful with spicy foods if you have a sore or infected mouth.
  • Gravies and bottled sauces can help to add flavour to a meal.
  • You might find you prefer stronger versions of your favourite foods for example smoked ham, bacon or stronger cheese.
  • You might prefer to avoid your favourite foods and drinks altogether during chemotherapy so there’s no danger of going off them for good. This is particularly useful advice for children.

Many things can cause bad breath. It can be worse if you also have a dry mouth. But good mouth care can cure most cases of bad breath. 

Tips for treating bad breath
  • Brush your teeth regularly.
  • Floss daily if your doctor agrees.
  • Use mouthwashes after cleaning your teeth or after eating.
  • Chew sugarless gum or suck on sugarless mints.
  • Drink plenty of water to keep your mouth moist. Swish the water around in your mouth for a few seconds to help remove any bits of food that may be stuck in your mouth or teeth.
  • Have regular dental check ups.

A dry or sore mouth can easily become infected. It is best to prevent mouth sores and infections.

Tips to help you
  • Check your mouth every day for sores or any other changes.

  • Tell your doctor or nurse if there are any problems.

  • Stick firmly to your mouth care routine. It is best to clean your teeth morning, night and after every meal.

  • Use anti fungal or other mouthwashes your doctor has prescribed even if you don't like them. They may suggest rinsing your mouth regularly with plain water or salt water.

  • A salt water mouth rinse can help to stop bacteria growing. Use 1 teaspoon of salt in 1 pint of cold or warm water. You can use this during the day as part of your mouth care routine. You'll need to make a fresh supply every day.

  • Stay away from foods that are sharp or crunchy which could scrape or cut your mouth such as crisps or French bread.

  • Avoid alcohol especially neat spirits, smoking and using toothpicks. These irritate the lining of your mouth and could make problems worse.

  • Sucking crushed ice during chemotherapy sessions can lower the risk of mouth ulcers by reducing blood flow to the mouth but it’s very important that you talk to your doctor before trying this.

Your nurse will give you a mouth care routine to follow if you have mouth sores (ulcers) or an infection. 

You might have mouthwashes or medicines to help protect the lining of your mouth, reduce pain and keep your mouth clean. Your doctor might prescribe anti fungal mouth rinses to help stop thrush infection.

It is important to take your medicines and use the mouthwashes exactly as your doctor or nurse advise.
Tips to help you
  • Brush your teeth regularly with a soft toothbrush using alcohol free mouthwash.
  • Using a baby's toothbrush is good.
  • You can clean your teeth with a foam mouth care stick or a piece of gauze dipped in the mouthwash if your mouth is too sore for a toothbrush. Ask your nurse for advice.
  • With sores in your mouth that are crusty, rinse with mouthwash several times a day to loosen the crusts.
  • You could try a gel mouthwash that sticks to the inside of your mouth and reduces pain from mouth ulcers. Ask your doctor or nurse about these.
  • Choose bland, soft foods such as mashed potato, well cooked rice or scrambled eggs if you’re able to eat.
  • Don't eat spicy or salty foods, dry or crisp foods, citrus fruits or juices.
  • It is important to drink plenty of liquids. Water is fine.
  • It’s much better to take painkillers and be able to eat and drink than to avoid eating because it's too painful.

When a person is very ill and weak, they can’t do their own mouth care. They may only be awake for short periods. Or they may be drowsy or sleeping all the time. It is still very important to regularly clean and moisten the mouth. This can help to make someone feel more comfortable.

If someone is awake, you can help them to drink. Or you can encourage them to have frequent sips of water, other drinks or ice chips. You can help a person gently clean their teeth or wash dentures for them. Some of the tips listed above on this page may be useful.

If someone is unconscious you can moisten their mouth regularly. You can do this with a sponge stick, using a small amount of water or mouthwash. Ask the healthcare team if they can provide or recommend some products for you.

Try to do a person’s mouth care when their head and shoulders are elevated on a pillow. If this isn’t possible, use a small amount of moisture and check fluid isn’t collecting inside the mouth.

Talk to the healthcare team and ask for support with this. Mouth care is one of the things that friends and relatives can do for the person with cancer. But you should also feel comfortable about doing it, so do ask for help if you need it.

  • Oral Care guidance and support in cancer and palliative care. Third Edition
    UK Oral Management in Cancer Care Group, June 2019

  • European Oral Care in Cancer Group – Oral Care Guidance and Support. 1st Edition
    Accessed April 2024 

  • Palliative care - oral. Clinical Knowledge Summaries​ 
    National Institute for Health and Care Excellence (NICE), revised 2018

  • Management of Oral and Gastrointestinal Mucosal Injury: ESMO Clinical Practice Guidelines  
    D E Peterson and others
    Annuals of Oncology, 2015

Last reviewed: 
23 Apr 2024
Next review due: 
23 Apr 2027

Related links