Mouth problems and cancer
Some cancer treatment can cause mouth problems. Your healthcare team can tell you how to look after your mouth during and after treatment.
How cancer treatment can affect your mouth
Some cancer treatments can damage the cells lining your mouth or throat. Your mouth may become very sore. Some people develop mouth ulcers. Soreness and ulceration of the lining of the mouth or throat is called mucositis. It can be very painful, but your healthcare team can prescribe painkillers and other medicines to help.
Mucositis can be caused by:
Most side effects get better when treatment ends. But sometimes side effects can be permanent.
Some people develop a fungal mouth infection called thrush (candidiasis). It can make eating unpleasant and change how things taste. Thrush can coat your tongue, the inside of your cheeks and the back of your throat. It looks red with white patches. Your doctor can prescribe an anti-fungal medicine to help.
Different members of your healthcare team can advise you on how to take care of your mouth during treatment. These include your:
- cancer doctor (oncologist)
- clinical nurse specialist (CNS) – a nurse who gives information about cancer, and support during treatment
- dietitian – someone who gives information and advice about food and food supplements
- speech and language therapist (SLT) – someone who gives information and support to people who have problems talking and swallowing
- therapy radiographer – someone who treats certain types of cancer with radiotherapy.
- dentist or dental hygienist.
They may look at your mouth to check for any problems. Tell them if your mouth becomes sore or if the soreness gets worse. They can give you something to help.
Related pages
Caring for your mouth
Many hospitals have their own mouth care guidelines for people having cancer drug treatments or radiotherapy. It is important to follow the advice of your healthcare team.
Looking after your teeth
Your cancer doctor or specialist nurse will be able to advise you. They may recommend using a high-fluoride or non-foaming toothpaste to help reduce any soreness.
- Use a soft toothbrush to clean your teeth gently.
- Do not rinse out toothpaste after you have cleaned your teeth. Just spit out any extra. This leaves a coating of fluoride on your teeth.
- Avoid using toothpicks.
- Check with your doctor or specialist nurse before using dental floss or interdental brushes. If you have a low blood platelet count, flossing may make your gums bleed.
Your doctor or specialist nurse may also advise you to see a dentist before you start treatment.
If you wear dentures
If you wear dentures, it is important to look after them. You are usually advised to clean them regularly with soap and water or a denture cleaning paste. If you use a denture cleaning solution, be careful to follow instructions and do not soak dentures for longer than advised. At night, clean and dry them, then store in a covered container.
Unless you are having radiotherapy, leave dentures out of your mouth for as long as you can during the day. This is to prevent them rubbing against your gums.
If you are having radiotherapy to the jaw area, you may be advised to keep your dentures in as much as possible during the day. Doing this can help to maintain the shape of your gums. If your mouth is very sore, talk to your healthcare team as it may feel more comfortable to leave your dentures out.
Using a mouthwash
Mouthwashes can be very soothing, but many of the ones you can buy in a chemist or shop may be too strong. They may irritate your mouth if it is dry and painful.
If your mouth is sore, a saltwater mouthwash can help reduce soreness. To make the mouthwash, add 1 teaspoon of salt to 900ml of cold or warm water (just under 2 pints). Rinse this around your mouth and spit it out. Then rinse your mouth with cold or warm water.
If your mouth is very painful, tell someone in your healthcare team. They can prescribe an anaesthetic gel or mouthwash if needed.
If your tongue is ‘coated’
This may make your food taste unpleasant and put you off eating. You can clean your tongue with a bicarbonate of soda solution. Dissolve 1 teaspoon of bicarbonate of soda in 570ml of warm water (1 pint). Dip a soft toothbrush or gauze in the solution and use it to clean your tongue. You can buy bicarbonate of soda in a chemist.
If this does not help, talk to your healthcare team. You may have oral thrush and need treatment.
If you are having radiotherapy for a head and neck cancer, talk to your healthcare team about how to look after your mouth and teeth.
Tips if you have a sore mouth
A sore mouth can make eating and drinking difficult. These tips may help:
Drinks
- Drink plenty of fluids, especially water.
- If fruit juices sting your mouth, try less acidic fruit juices, squashes or cordials. These include peach nectar or blackcurrant squash. You could freeze juice in an ice cube tray and suck on the cubes to soothe your mouth.
- Avoid fizzy drinks if they sting your mouth.
- Try milk or milk-based drinks, such as malted drinks, milkshakes and hot chocolate. These can be made using cow’s milk, goat’s milk or a plant-based alternative such as soya, rice or oat milk.
- Cold food and drinks may be soothing. Try ice cream, soft milk jellies or adding crushed ice to drinks.
- Very hot drinks can irritate your mouth, if it is sore. Some people find it better to have drinks that are lukewarm or at room temperature.
- Try drinking through a straw.
Food
- Salty, spicy or acidic food may irritate your mouth, but some people may still enjoy these foods.
- Try to avoid rough-textured food like toast or raw vegetables.
- Keep your food moist by adding sauces and gravies.
- You may find taking painkillers before meals will help. Ask your specialist nurse for advice about what to use. They may suggest using soluble paracetamol that you can rinse around the inside of your mouth before swallowing.
Tips if you have a dry mouth (xerostomia)
Radiotherapy to the head and neck area, and treatment with some cancer drugs, can damage the salivary glands. This may cause a dry mouth.
The following tips may help you cope with a dry mouth during and after cancer treatment:
- Take frequent sips of water or a sugar-free drink. Keep a glass of water by your bed and carry a drink with you when you go out.
- Try sucking ice cubes or lollies. You can make lollies by freezing fresh fruit juice or squash in ice cube trays or lolly containers with sticks.
- Add moisture to make food easier to swallow, especially dry and starchy foods like bread, biscuits, crackers and potatoes. For example, moisten foods with gravies, sauces, extra oil, salad dressings, yoghurt, mayonnaise or butter.
- Chew your food well and take sips of fluid between mouthfuls.
- Chew sugar-free gum. This can sometimes help you to produce more saliva.
- Tell your doctor. They can prescribe mouthwashes, lozenges, saliva substitute sprays, gels or tablets if needed.
- Use a lip balm to protect your lips. If you are having radiotherapy or oxygen therapy, you must not use a petroleum-based lip balm such as Vaseline®. Use a water-based lip balm instead. Your clinical nurse specialist or radiotherapy team can advise you about this.
- Try using an atomiser spray with cool water to keep your mouth moist. Take it with you when you go out.
- Try to avoid alcohol, especially spirits, as these can irritate your mouth. This includes mouthwashes that contain alcohol.
- Do not smoke, as this can irritate your mouth and make it feel dry.
- Try to limit caffeinated drinks, and acidic food and drinks such as citrus fruit.
Tips for coping with changes to taste
You may find that food tastes different or that you lose your sense of taste during treatment.
Food may taste bland, metallic, very salty or too sweet. Sometimes all food tastes the same.
These changes are usually temporary but sometimes can be permanent.
The following tips may help:
- Try different foods to find out what tastes best to you. Eat foods that you enjoy.
- Use seasonings, spices and herbs such as pepper, cumin or rosemary to flavour your cooking. But if your mouth is sore, you may find that some spices and seasonings make it worse.
- You may find it better to eat bland foods such as bread, potatoes and crackers.
- Try marinating meat in fruit juice or a sauce before cooking it.
- Cold meats may taste better served with pickle or chutney.
- Sharp-tasting foods can be refreshing and leave a pleasant taste in your mouth. These include fresh fruit, fruit juices and sugar-free sour or boiled sweets. Be careful if your mouth is sore as these may be painful to eat.
- If you no longer like tea or coffee, try fruit or herbal teas, milk or a cold drink.
- Some people find that cold foods taste better than hot foods. You may find it helps to let your food cool before eating it.
- Serve food with sauces to add flavour. But be careful if your mouth is sore as some sauces, such as curry or sweet and sour, may feel painful to eat.
- If you notice a metallic taste in your mouth, try using cutlery made of plastic, wood or bamboo.
- Brushing your teeth before meals may be helpful.
Tips for coping with difficulties chewing or swallowing
Some cancer treatments can affect the cells in the lining of the throat. This includes some anti-cancer drugs and radiotherapy for head or neck cancer. This can make it painful to chew or swallow.
An infection in your mouth or throat, such as thrush, can also make chewing and swallowing uncomfortable.
Tell your doctor or dietitian if you have any difficulties chewing or swallowing. If having a drink makes you cough, and you are feeling unwell, you should tell your doctor or nurse as soon as possible.
A speech and language therapist (SLT) can advise you about swallowing problems.
Here are some tips to help with difficulties chewing or swallowing:
- Take painkillers 30 minutes before meals. This may make it easier to chew and swallow food. Your healthcare team can advise you about which painkillers to take. Tell your doctor or nurse if you find it difficult to swallow tablets. They will prescribe you liquid medications.
- Choose soft foods that are easy to swallow, such as scrambled eggs or tofu, custard, milk puddings or yoghurt.
- Soften foods with sauces and gravy.
- Chop meat and vegetables finely and cook them for a long time. For example, you could make a stew or casserole.
- Cut the crusts off bread to make softer sandwiches. Some people find thin bread easier to swallow. Your dietitian or SLT may advise you to stop eating bread, as it can be hard to digest and swallow. You may find crackers easier to swallow.
- If you have a blender or food processor, you could liquidise cooked foods.
- Consider ordering frozen meals for delivery. Some companies have a soft-food range.
- You may find it easier to replace some meals with a meal supplement drink There are lots of different ones available. Your dietitian can provide nutritional advice and prescribe supplement drinks if needed. You can buy some at pharmacies or online, such as Complan®, Meritene® or Aymes Retail drinks. Always talk to your doctor or dietitian before taking supplement drinks. They can explain which might be best for you.
About our information
This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer.
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References
Below is a sample of the sources used in our information about mouth problems. If you would like more information about the sources we use, please contact us at informationproductionteam@macmillan.org.uk
Oral Care guidance and support in cancer and palliative care. Third edition. UK oral Management in Cancer Care Group (UKOMiC) Available from www.ukomic.com/documents/UKOMiC-Guidance-3rd-Edition.pdf [accessed July203].
Lalla RV, Bowen J, et al. MASCC/ISOO clinical practice guidelines for the management of mucositis secondary to cancer therapy. Cancer. 2014; 120(10): 1453–1461. Available from doi: 10.1002/cncr.28592 [accessed July 2023].
Mouth Care Matters. A guide for hospital healthcare professionals, Second edition. Health Education England. 2019. Available from mouthcarematters.hee.nhs.uk/wp-content/uploads/sites/6/2020/01/MCM-GUIDE-2019-Final.pdf [accessed July 2023].
Acute Oncology Initial Management Guidelines. Version 4.0 UKONS. 2023. Available from www.ukons.org/site/assets/files/1067/ukons_ao_initial_management_guidelines_final_version_2023.pdf [accesses July 2023].
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