Mouth problems

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Mouth sores and ulcers

Mouth sores and ulcers are a common side effect of chemotherapy and radiation therapy. This is known as oral mucositis. The sores can form on any soft tissue in your mouth, making eating, swallowing and talking difficult. This is usually short-term and goes away as you recover from treatment.

Your doctor can give you medicines to reduce the pain when you eat, drink or speak. Some pain relief medicines can be applied directly to the mouth sores to numb them.

Your dietitian can suggest foods to reduce discomfort. You may need to choose softer foods and nourishing fluids. If you are unable to eat and drink enough to meet your nutritional needs, you may need a feeding tube to support you during recovery.

For more on this, see Mouth health and cancer treatment.

Dry mouth

Radiation therapy to the head or neck area can cause dry mouth (xerostomia), which is often long-lasting. This can make chewing, swallowing and talking difficult. A dry mouth can also make it harder to keep your teeth and mouth clean, which can increase the risk of damage to your teeth. See the table below for some ways to manage a dry mouth.

How to relieve mouth problems

Mouth sores and ulcers

Dry mouth

  • Talk to your doctor about mouthwashes or medicines to relieve pain and to help with healing.
  • Use a soft-bristled toothbrush and replace it often to reduce infections. Brush gently after meals and before going to bed.
  • Suck on ice cubes.
  • Avoid rough, crunchy or dry foods (e.g. chips, nuts, toast, crackers). Also avoid vinegar, spices, salty foods, alcohol, very hot or very cold foods and drinks, and citrus or tangy tomato-based food and juice.
  • Gargle with ½ tsp salt plus ½ tsp baking soda in a glass of warm water. Use frequently as a mouthwash.
  • Use a lip balm to keep your lips moist.
  • Tell  your doctor or dietitian if you are eating and drinking less because it is difficult to swallow.
  • Ask your dentist about an oral care plan and have regular check-ups.
  • Carry a water bottle and have regular sips throughout the day.
  • Limit alcohol and caffeinated drinks as these are dehydrating, and avoid smoking.
  • Add moisture to meals with extra sauce or gravy.
  • Chew sugar-free gum to encourage the flow of saliva.
  • Soften food by dipping it into milk or soup, or moisten it with gravy, sauce, cream or custard.
  • Take drinks with meals to help soften the food and make it easier to swallow.
  • Acupuncture may help to improve dry mouth. Talk to your doctor before trying acupuncture.
  • Use artificial saliva, lubricating agents or dry mouth gels available from the chemist. Swirl grapeseed oil in your mouth and then spit out.

Click on the icon below to download a PDF fact sheet on mouth health

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Instructions for downloading and reading EPUB files

Apple devices

The iBooks application must be installed on your Apple device before you can read the EPUB.
Different ways to download an EPUB file to your Apple device:

  • email EPUB files to yourself and transfer the attachment to iBooks.
  • copy EPUB files into DropBox (or a similar service) and use the DropBox app to send them to iBooks.
  • open EPUB files directly from Mobile Safari and open them in iBooks, where they are saved automatically by downloading the EPUB from the website.

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To download an EPUB file to your Kobo from a Windows computer:

  • download and save the EPUB directly onto your desktop.
  • connect your Kobo to your computer using the USB cable and tap “Connect” on your eReader.
  • select “Open folder to view files” to view the contents of your Kobo.
  • navigate to where you have stored your EPUB file in “Finder”, in documents or downloads, and drag and drop it into the Kobo window. You can now disconnect your Kobo to read the eBook.

To download an EPUB to your Kobo from a Mac:

  • download and save the EPUB directly onto your desktop.
  • connect your Kobo to your computer using the USB cable and tap “Connect” on your eReader.
  • open your “Finder” application.
  • select “Kobo eReader” from the listed devices to view the contents of your Kobo.
  • navigate to where you have stored your EPUB file in “Finder”, probably in documents or downloads, and drag and drop it into the Kobo window. You can now disconnect your Kobo to read the eBook.

Turn on your Kobo and your EPUB will be located in “eBooks”, while a PDF will be located in “Documents”.
Need more information? Visit:

Sony Reader

To download an EPUB file on your Sony Reader™:

  • ensure you have already installed the Reader™ Library for PC/Mac software
  • select the eBook you want from our website and click the link to download it.
  • connect the Reader™ to your computer.
  • open the Reader™ Library software and click “Library” in the left-hand pane and select the eBook to view it.

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Amazon Kindle 2nd Generation devices

EPUB files can’t be read on the Amazon Kindle™. However, like most eReaders, Kindle™ 2nd Generation devices are able to display PDFs. We recommend that you download the PDF version of this booklet if you would like to read it on a Kindle™.
To transfer a PDF to your Kindle™ via USB cable from your computer or Mac:

  • download the PDF directly onto your computer.
  • connect the USB cable to your computer’s USB port, and the micro USB end of the cable to your Kindle™. Note: the Kindle™ won’t be available as a reading device while it is connected to your computer until it has been disconnected.
  • open the Kindle™ drive and several folders will appear inside. The “Documents” folder is where you will need to copy or drag the PDF to.
  • safely eject your Kindle™ from your computer and unplug the USB cable. Your content will appear on the Home Screen.

Kindle also provides a Kindle Personal Documents Service that allows users to send documents as an attachment directly to your eReader. For more information on this service, visit
For more information on accessing a PDF on your Kindle™, visit, log in to your account and click on Personal Document Settings.
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Android and PC

You can also download and open eBooks on Android devices and PCs with appropriate apps or software installed. Suitable eReader apps for Android include Google Play Books, FBReader and Moon+ Reader. Suitable software for PCs include Calibre and Adobe Digital Editions.

This information was last reviewed in September 2019
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