Mucositis

Also called Oral mucositis or Sore mouth from cancer treatment

Mucositis is when the lining of the mouth becomes sore and inflamed. It is a common side effect of chemotherapy and radiotherapy to the head and neck. It usually starts a few days after treatment and gets better a few weeks after treatment finishes. It can make eating, drinking and talking painful.

Last updated Nov 9, 2026

What it is

Good mouth care, soft foods, mouthwashes, painkillers and sometimes special gels can help.

Mucositis can increase the risk of infection, so the cancer team should be told about it.

Common signs

  • A sore, red mouth
  • Mouth ulcers
  • Difficulty eating, drinking or talking
  • Dry mouth
  • White patches, which may be an infection

How it is usually diagnosed

  • Examination of the mouth by the cancer team

Records worth keeping

Keeping these together makes each appointment easier, especially when you see a new doctor:

  • Cancer team notes
  • Mouth care plans
  • Treatments used

Questions to ask your doctor

  • What mouth care should I do each day?
  • Which painkillers can I use?
  • What should I eat while my mouth is sore?

When to get help right away

Call 112 or go to the nearest emergency department if you have:

  • A temperature of 38°C or above, being unable to drink, or feeling very unwell during cancer treatment: call your cancer care team or 112 straight away

This page is general information. It is not a diagnosis and does not replace a doctor who knows your history. Medfold keeps your records organised; it does not interpret them.

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