Mouth health

Your treatment team will discuss the oral side effects that you may experience and suggest ways to manage them. Common oral side effects are:

• Mouth changes – You might have mouth sores and ulcers (oral mucositis), thick saliva or a dry mouth (xerostomia).
• Tooth decay – Your teeth may be at increased risk of decay, especially if you have a dry mouth.
• Mouth infections – The most common infection is oral thrush, which usually appears as white or red patches, or a white/yellow coating on the mouth and tongue. Thrush can affect your taste, cause bad breath and be uncomfortable. Your treatment team can prescribe medicine to help treat mouth infections.
• Bleeding gums – Your gums may look red, shiny or swollen and they may bleed. Bleeding may occur if you don’t have enough platelets in your blood, which can happen with chemotherapy. Platelets help the blood to clot.
• Taste changes – Cancer treatment may make foods taste different (e.g. bland, bitter or metallic). You may lose interest in eating (loss of appetite).
• Trouble swallowing (dysphagia) – Treatment to the head and neck area can affect swallowing. If you are having difficulty swallowing, you can ask your doctor for a referral to a speech pathologist.
• Difficulty opening your mouth (trismus) – This can be caused by the cancer or cancer treatments. If opening your mouth is difficult, a speech pathologist may be able to help you.

If you are experiencing side effects, tell your treatment team and they may prescribe medicine to manage pain or symptoms or suggest ways to make eating, drinking and swallowing easier.

Your doctor may refer you to a dietitian or speech pathologist to help you manage your oral side effects and make eating and drinking easier.

For more information about caring for your mouth, see Taste and smell changes and Nutrition.

Oral mucositis

Some treatments – for example, radiation therapy to the head or neck area, some chemotherapy and targeted therapy drugs – can damage the cells lining the mouth. This is known as oral mucositis. Symptoms include:

• painful spots, sores or ulcers in your mouth
• bleeding in the mouth
• mouth infections such as oral thrush
• discomfort and pain when eating, drinking, speaking or wearing dentures
• sensitivity to certain foods and drinks.

Some medicines help to reduce the discomfort when you eat, drink or speak, and can be applied directly to the mouth sores to numb them. Mucositis usually gets better a few weeks or months after treatment ends.

Dry mouth and saliva changes

Radiation therapy or surgery to the head or neck area, some chemotherapy drugs and some pain medicines can reduce the amount of saliva (spit) in your mouth or make your saliva thick and sticky. Symptoms include:

• not having as much saliva as usual
• thick or stringy saliva
• a sticky or dry feeling in your mouth
• problems chewing, tasting and swallowing 
• difficulty speaking (your tongue may have trouble moving) 
• ridges or cracks on the tongue or corners of the mouth 
• difficulty with swallowing saliva or spitting it out 
• a thick coating on the tongue
• taste changes.

How quickly these symptoms improve is different for every person. Talk to your treatment team about what to expect after treatment.

• Rinse your mouth several times a day – ask your treatment team what type of alcohol-free or homemade mouthwash to use and how often to use it.
• If you wear dentures, make sure they fit properly. Take them out after eating and clean them well. Keep them dry when you’re not wearing them.
• Clean your teeth with a soft-bristled toothbrush and replace regularly (at least every three months) to prevent infection. Use a mild fluoride toothpaste recommended by your dentist.
• Avoid whitening toothpastes, which may irritate your mouth and gums. 
• If your mouth is too sore to brush, or bleeds when you clean your teeth, rinse it using the mouthwashes recommended by your treatment team.

• Visit your dentist before having treatment for cancer.
• Tell your treatment team if you notice any changes to your mouth – they may prescribe medicines and mouthwashes that can make you more comfortable. 
• If you are struggling to eat enough food or you notice you are losing weight, ask to speak to a dietitian.
• Ask a speech pathologist or dietitian what you can eat or drink if you are having difficulty or pain when swallowing food or drink.
• Find a speech pathologist or an accredited practising dietitian.
• Talk to your doctor and nurse about medicines to relieve pain and help with healing.

• Drink 6–8 glasses of water and fluids throughout the day. Carry a water bottle with you and take frequent sips.
• Limit how much caffeine you drink (e.g. from coffee, tea, energy drinks or soft drinks) and reduce alcohol, as both can increase dryness in the mouth.
• Suck on ice chips or ice blocks, eat soft sugar-free sweets, or try sugar-free chewing gum.
• Eat soft foods that are moist and easy to swallow, such as rice, mashed potatoes, mashed vegetables, tinned fruit, soup, scrambled eggs, yoghurt, custard and minced or slow-cooked meat, chicken or fish. Use gravies and sauces to add flavour and make foods easier to eat.
• Avoid dry, rough or crunchy foods that irritate your mouth (e.g. chips, nuts, toast, crackers), vinegar, spices, salty foods, alcohol, very hot or very cold foods and drinks, and citrus or tangy tomato-based food and juice.
• Drink through a straw if you have mouth sores. Paper or silicone straws may taste better than metal straws.
• If you are eating less or losing weight, choose nourishing drinks like milk, smoothies or nutritional supplements.

• Check your mouth, tongue and teeth for changes daily during treatment. Any white spots or pain might mean an infection.
• Consider using a cool mist humidifier at night. This can be helpful if you have a very dry mouth.
• Quit smoking or vaping as it will irritate your mouth and make dryness worse.
• Your dentist may be able to apply fluoride treatments, which can slow any tooth decay.
• Keep lips moist with a lip balm containing beeswax, shea butter, lanolin or plant-based oils. Avoid lip balms based on petroleum jelly.