Looking after your mouth during chemotherapy

Chemotherapy can cause side effects in the mouth, including:

  • dry mouth
  • taste changes
  • sore mouth
  • mouth infections.

There are things you can do to help you cope with these problems. It’s important to tell your doctor or nurse if you develop mouth problems. They can check for infections and give you advice about your situation. If you feel unwell or have a high temperature, contact the hospital.

You may be advised to use certain mouthwashes, protective gels or painkillers to ease any discomfort you have. If your mouth problems mean you are finding it difficult to eat or drink enough, tell your doctor or nurse. They can prescribe supplements or treatments that can help.

Some people find that chemotherapy affects their appetite and sense of taste. There are ways to make your food more appealing. You may find it helpful to discuss this with a dietitian at the hospital.

Although these side effects are unpleasant, they will improve and gradually go away after your treatment is over.

Coping with mouth problems during chemotherapy

This information has some tips to help you cope with common mouth problems during chemotherapy. Always tell your nurse or doctor if you develop mouth problems. They can give you specific advice and may prescribe treatments to help.

Dry mouth

If your mouth is dry, take sips of water often. Moisten foods with sauces and gravies. Sucking on sweets, ice cubes or an ice lolly can help.

Some people are prescribed saliva replacement products. You’re most likely to need these if you are having radiotherapy to the head and neck as well as chemotherapy. They come as gels, sprays and tablets and are designed to have a similar consistency to saliva.

Taste changes

Chemotherapy can affect your taste buds. This can make food and drinks taste different to you. When treatment is over, your taste will gradually return to normal. If your taste is affected, try different foods and drinks to see what tastes best to you.

Sore mouth

Tell your nurse or doctor if your mouth is sore. They will check for problems such as infection or ulcers and may prescribe mouthwashes, painkillers or other treatments to help.

Mouthwashes, gels and sprays to ease soreness

Regularly rinsing your mouth with a saline mouthwash or one prescribed by your nurse or doctor can help to ease soreness. If it is too sore to brush your teeth, your nurse may suggest gently cleaning around teeth and gums with a swab soaked in saline mouthwash.

Your doctor or nurse may prescribe a gel, spray or mouthwash that forms a protective coating over sore areas in the mouth. You apply gels such as Orabase® and sprays like Episil® directly to sore areas in your mouth. Your nurse may advise you to use a mouthwash, such as Caphosol® or Gelclair®, several times a day and before eating. Or they may prescribe a benzydamine mouthwash, such as Difflam®. It contains a local anaesthetic to numb the mouth, which makes it easier to eat and drink.

Painkillers to ease soreness

Painkillers can help ease mouth soreness. It is important to take painkillers regularly as prescribed. This keeps a constant level of painkiller in your blood so that it works more effectively for you.

If you find swallowing pills difficult, there are liquid and soluble painkillers. If mild painkillers like paracetamol don’t control the pain, let your doctor know. They may prescribe something stronger, such as codeine combined with paracetamol (co-codamol). For severe mouth pain, doctors may prescribe strong painkillers such as morphine.

Painkillers containing codeine and morphine can make you constipated. You will usually be prescribed a laxative to take while you’re taking them. You may have to adjust the amount of laxative you take to manage your constipation.

Eating and drinking with a sore mouth

For a few people, mouth pain can even make it difficult to drink liquids. This is more likely in people having high-dose chemotherapy. If this happens, you may have to be admitted to hospital to be given fluids and painkillers by drip into a vein (intravenously).

Soft, bland foods are usually easier to eat when your mouth is sore. If you have problems eating, tell your doctor or nurse. They may refer you to a dietitian for extra support and advice. Food supplements such as Build-Up® or Complan® can help you to get extra energy and nutrients. You can buy them from chemists and some supermarkets. Your doctor, nurse or dietitian may also prescribe food supplements.

If you are having high-dose chemotherapy or radiotherapy to the head and neck combined with chemotherapy, you may need extra support to get the nutrition you need. This may involve being fed through a tube that goes up the nose and down into the stomach (nasogastric tube). Or, some people are given specially prepared nutrition directly into a vein (intravenously).

Mouth infections

During chemotherapy, you are more likely to get an infection in your mouth. This is why it is important to keep your mouth as clean as possible. Infection can happen because chemotherapy temporarily thins the lining inside your mouth. This makes it less good at keeping bugs like bacteria, viruses or fungi out. Chemotherapy also reduces the number of white blood cells in your blood. These cells fight infections, so when they are low your body isn’t as good at fighting infection.

The most common mouth infection is called thrush. Thrush usually appears as white patches, or a white coating, over the lining of the mouth and tongue. It can also cause bad breath. It is treated with anti-fungal drugs. These can be tablets (fluconazole) or a liquid you put on your tongue (nystatin). Doctors sometimes prescribe these treatments to prevent thrush in people having chemotherapy.

Rarely, an infection in your mouth can enter your bloodstream and make you very unwell. Your specialist doctor or nurse may ask you to check your temperature regularly, and to contact the hospital if you feel unwell or if your temperature is high. A high temperature may be over 37.5°C (99.5F).

Having mouth problems can sometimes be difficult to cope with. But they will gradually improve and eventually go away after your treatment is over. You can contact our cancer support specialists on 0808 808 00 00 for more information and support.

Caring for your mouth during chemotherapy

Keeping your mouth as clean as possible during your treatment will help to prevent or reduce side effects in your mouth. Check inside your mouth once a day for any signs of:

  • redness
  • swelling
  • ulcers
  • white patches
  • bleeding.

Your nurse at the hospital can show you how to do this.

Clean your teeth morning and evening and after meals. Replace your toothbrush every three months or sooner if the bristles are spread out of shape. A toothbrush with soft bristles, or a toothbrush for babies or young children, is gentler on your gums if your mouth is sore.

Chemotherapy can cause sickness. If this happens, you should rinse your mouth out with water after being sick. Try to brush your teeth clean as soon as you feel able to after being sick.


Use fluoride toothpaste to clean your teeth. If your usual brand irritates your mouth, or if your mouth is sore, choose a mild-flavoured, non-foaming toothpaste. Some people find children’s toothpaste less irritating. You can ask your nurse if there is one they recommend. Non-foaming brands include:

  • Biotene fluoride®,
  • Sensodyne Pronamel Daily protection®
  • Corsodyl daily®
  • Sensodyne Daily Care®.

You can buy them in larger chemists or online.

Dental floss or tape

Check with your nurse or doctor if it’s all right for you to use dental floss or tape once a day to clean between your teeth. Avoid toothpicks, as they can damage your gums. There may be times when it is best not to floss. This is because flossing can make your gums bleed if your platelets are low. Platelets are tiny blood cells that help stop bleeding.


If you wear dentures, clean them with a separate toothbrush and a denture cleaning cream. Clean and rinse them morning, night and after eating. Before you go to bed, soak your dentures in a denture cleaning solution then leave them in a container of water overnight. This will give your mouth a rest and reduce the chance of mouth infections.


Avoid mouthwashes that contain alcohol as they can irritate your mouth. If your doctor or nurse prescribes a mouthwash for you, use it as prescribed. Otherwise, rinse your mouth with a saline (salty water) or bicarbonate of soda mouthwash four times a day.

To make a saline mouthwash, add one teaspoon of salt to one pint of cold or warm water.

To make a bicarbonate of soda mouthwash, add one teaspoon of bicarbonate of soda to cold or warm water.

Make a fresh solution of mouthwash each day. After using the mouthwash, rinse your mouth with water.

Looking after your lips

Keep your lips moist by using Vaseline® or a lip balm. If you’re having radiotherapy to your head or neck, check with your radiotherapy team or specialist nurse before using any products on your lips.

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