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What is mucositis?

Mucositis is a condition characterised by pain and inflammation of the surface of the mucous membrane. The mucous membrane is the soft layer of tissue that lines the digestive system from the mouth to the anus.

Mucositis is often divided into two main types, including:

  • oral mucositis,which occurs inside the mouth and can cause painful
    mouth ulcers
    (sores) to develop
  • gastrointestinal mucositis, which occurs inside the digestive system and often causes

It is also possible for mucositis to affect the lining of the anus – a condition known as proctitis.

Read more about the

symptoms of mucositis

Why does mucositis happen?

Mucositis develops as a side effect of

when it is aimed at cancerous cells around the mucous membrane.

Patients receiving radiotherapy for other cancers, such as breast cancer, will not usually develop mucositis because the therapy is not targeted near the mucous membrane.

The radiation used during radiotherapy and the powerful medicines used in chemotherapy damage the cells of the membrane and cause the symptoms of mucositis.

Radiotherapy can produce mucositis confined to the area that is treated, and this will depend on the site of the tumour. Mucositis related to chemotherapy is due to the specific drugs used, rather than the site of the tumour.

If you are undergoing cancer treatment that may cause mucositis, you will be checked regularly for the condition. Mucositis can usually be diagnosed after an examination or a description of your symptoms.

Read more about the

causes of mucositis
diagnosing mucositis

How is mucositis treated?

The main aim of treatment for oral mucositis is to prevent infection and reduce any pain. This is done by practicing good oral hygiene and by using painkillers.

However, there are also some treatments available to reduce the symptoms of oral mucositis, such as low-level laser therapy (LLLT), honey, antibiotic pastilles and palifermin.

Treatment for gastrointestinal mucositis aims to reduce the main symptoms of the condition, such as

and inflammation. This is done through a combination of medicines and self-care measures.

The symptoms of mucositis should begin to improve a few weeks after chemotherapy or radiotherapy has finished, although it can sometimes take longer.

Read more about

treating mucositis


The most serious cases of mucositis can lead to a number of associated health complications.

Many people with mucositis find it painful to swallow food and require alternative feeding methods, such as a feeding tube.

Also, mouth ulcers can become infected with bacteria. The infection can spread to the blood and then on to other organs. This is known as

and can be life-threatening.

Read more about the

complications of mucositis

Can mucositis be prevented?

Some treatments can be taken during radiotherapy or chemotherapy to try to reduce the severity of mucositis or how long it lasts. However, it is not always possible to prevent it.

Treatments include medications such as palifermin, benzydamine, sulfasalazine and amifostine.

Read more about

preventing mucositis

Mucositis symptoms

The symptoms of mucositis depend on whether your mouth or digestive system is affected.

Oral mucositis

The symptoms of oral mucositis usually begin five to 10 days after starting

, or 14 days after starting

The tissue inside your mouth will start to feel sore, as if you have burnt it by eating very hot food. It is also likely you will develop white patches or ulcers on the lining of your mouth and, in some cases, on your tongue and around your lips.

The ulcers can feel very painful and may make it difficult for you to eat, drink and talk. They may also bleed and become infected.

You may also have a dry mouth and a reduced sense of taste. These changes in your mouth may make it more difficult to speak. Relatives and friends may notice your breath smells bad.

The symptoms of oral mucositis should ease three to four weeks after your course of chemotherapy or radiotherapy has finished. However, it can take longer – around six to eight weeks – if you have had radiotherapy of your mouth.

Gastrointestinal mucositis

The symptoms of gastrointestinal mucositis are more common in people receiving chemotherapy, although they may also occur if you have had radiotherapy to treat cancer in your abdominal (tummy) or pelvic area.

The symptoms of gastrointestinal mucositis usually begin 14 days after you start your chemotherapy or radiotherapy. They can include:

  • diarrhoea
  • ulcers in your anus and rectum
  • rectal bleeding
    , which can cause blood in your stools
  • passing mucus from your anus (back passage)
  • abdominal pain
  • difficulty swallowing (
  • nausea (feeling sick)
  • bloating

Most of these symptoms will stop a few weeks after your treatment has finished, although occasionally the symptoms of diarrhoea can persist for several months after radiotherapy has finished.

Mucositis causes

Mucositis is usually a side effect of cancer treatment.

Radiotherapy and chemotherapy

are very effective treatments for killing cancer cells but can also damage healthy cells, particularly cells in your mucous membrane, which are more vulnerable to damage. The mucous membrane is the soft layer of tissue that lines your digestive system, from the mouth to the anus.

Radiotherapy and chemotherapy damage the DNA of the cells on the lining of your mucous membrane, which damages the cells and prevents them from regenerating.

This causes the layer of tissue that lines your mucous membrane to eventually break down and ulcers will form. Your cancer treatment team will make every effort to limit the damage to your mucous membrane, but it is not always possible to prevent damage occurring.

Biological therapies

Biological therapies, also called targeted therapies, are another type of cancer treatment that can cause oral mucositis.

Some cases are thought to be different from mucositis caused by radiotherapy or chemotherapy, although at the moment they are poorly understood.

Increased risk

Certain things can increase your risk of developing mucositis, or may increase your risk of mucositis being severe. These include:

  • being younger – oral mucositis is more severe in young people
  • smoking
  • drinking alcohol
  • eating spicy foods
  • dehydration
  • having a dry mouth during your treatment – a dry mouth is another side effect of radiotherapy and chemotherapy
  • not looking after your mouth properly before and during treatment – for example, by not brushing your teeth regularly
  • receiving a higher dose of chemotherapy or being treated with chemotherapy for a long time
  • receiving high-dose radiotherapy to your mouth or neck

Mucositis can also sometimes develop during and after a stem cell transplant (

bone marrow transplant
). This is because cancer treatments are used in combination with medicines that reduce the effectiveness of your immune system (the body's natural defence against infection and illness) during this procedure.

Diagnosing mucositis

Mucositis can usually be diagnosed after a physical examination and a description of your symptoms.

Oral mucositis

If you are receiving high-dose

, it is likely you will receive regular (weekly) assessments for mucositis until the risk of developing the condition has passed.

To confirm a diagnosis of oral mucositis an assessment is made by:

  • examining your mouth
  • asking you about any symptoms of pain that you have
  • checking you are still able to eat and drink properly

Healthcare professionals use a grading system to determine how serious the symptoms of oral mucositis are. There are several different grading systems available.

The World Health Organization (WHO) uses the grading system described below.

  • grade one: you are experiencing symptoms of soreness but there are no ulcers in your mouth
  • grade two: you have ulcers in your mouth but are still able to eat solid food
  • grade three: you are no longer able to eat solid food but can still swallow liquids
  • grade four: you are unable to swallow solid foods or liquid

Cases of grade one or two mucositis can usually be treated at home. Cases of grade three and four mucositis will usually require admission to hospital so you can be given nutritional support and your general health can be carefully monitored.

Read more about

treating mucositis

Gastrointestinal mucositis

A diagnosis of gastrointestinal mucositis can usually be made by asking you about your symptoms.

In rare cases, further testing may be required if it is thought that a serious complication has occurred due to your gastrointestinal mucositis. For example, a bowel obstruction (blockage) or a perforated (burst) intestine may be diagnosed using a

computerised tomography (CT) scan
. This is where multiple X-rays are taken at slightly different angles and put together by a computer to create a detailed image of the inside of your body.

Mucositis treatment

There is no single treatment for mucositis, as it largely depends on which type of mucositis you have and exactly what caused it.

For example, things that are effective for oral mucositis caused by

may not be helpful if you have gastrointestinal mucositis caused by high-dose

Oral mucositis


If you have oral mucositis, it is very important you have a good oral hygiene routine because it can reduce the severity of your symptoms and how long you experience them.

Below is some general advice on good oral hygiene. However, always follow any advice your cancer treatment team gives you if it differs from the advice below.

  • Brush your teeth every morning and evening and after every meal.
  • Use a toothbrush with soft bristles.
  • Replace your toothbrush regularly. Most toothbrushes need to be replaced every three months.
  • Floss your teeth at least once a day or as advised by your treatment team.
  • Rinse your mouth five or six times a day using a bland rinse. A bland rinse is a mixture of water and sodium bicarbonate (baking soda) or a mixture of water and salt (to make a saline solution). Your treatment team will be able to advise you about the type of bland rinse suitable for you.
  • Do not use a mouth rinse that contains alcohol.
  • Avoid tobacco, alcohol and irritating foods, such as hot, spicy, acidic or rough foods.
  • Use a water-based moisturiser to protect your lips.
  • Make sure you drink plenty of fluids throughout the day. A minimum of 1.2 litres (2 pints) is the recommended daily amount.

Ice cubes

Sucking ice cubes or ice chips is sometimes recommended as a way of providing relief from the symptoms of oral mucositis.

The healthcare professionals treating you will advise you about whether ice cubes could help you or not.

Pain relief

Oral mucositis is often painful, but there are several kinds of painkillers available that you can try. You may be given painkillers in the form of a mouth rinse, gel or spray.

If a painkiller is not effective, other medicines can be tried alongside it, or a stronger painkiller can be used. Worsening pain does not always mean you will need to be admitted to hospital, and in most cases you can take the painkilling medication yourself at home.

If a simple painkiller such as

doesn't work, you may then be prescribed a stronger type of painkiller, such as codeine. If this is still not effective, a stronger opioid can be prescribed, such as morphine.

Non-steroidal anti-inflammatory drugs (NSAIDs)
may provide pain relief for some people. However, if you are receiving some types of chemotherapy, NSAIDs could damage your kidneys and affect the way they work. For this reason, you should only take painkillers as advised by your treatment team.


Palifermin is a type of medication that has proved to be successful in treating people having a stem cell transplant (

bone marrow transplant
), which usually includes chemotherapy or radiotherapy.

Palifermin encourages the growth of new cells on the lining of the mucous membrane. This growth is thought to reduce the severity of your symptoms and encourage any ulcers to heal faster. Palifermin also stops sores forming, so can be used to prevent, as well as treat, mucositis.

Palifermin is given by injection. You should receive an injection once a day for three days before your chemotherapy or radiotherapy, and then for three days afterwards, for a total of six doses.

Common side effects of palifermin include:

  • skin rash, itchiness and redness
  • an increase in the thickness of the lining of your mouth or tongue
  • a change in the colour of your mouth or tongue
  • aching joints
  • altered taste

Less common side effects include swelling of the face or mouth.

The side effects should pass after you have completed the course of palifermin.

Low-level laser therapy (LLLT)

Low-level laser therapy (LLLT) is another treatment that can reduce the severity of oral mucositis. It involves focusing low-energy lasers (beams of light) at affected tissue. LLLT is thought to work by stimulating certain cells that then help to speed up the healing process.

As LLLT requires specialist equipment and training, it may only be available at specialist cancer centres or clinics.

Infected ulcers

The mouth ulcers (sores) that mucositis causes can become infected. If this happens, your treatment team may prescribe medication for this. You may also be given a special mouth wash to use to prevent further infections.

Mucositis may increase the risk of oral thrush, which can be treated with antifungal medicines. Read more about treating oral thrush.


Gastrointestinal mucositis can sometimes lead to

, which can be treated in a number of ways. Some of these are described below.


It is very important you drink plenty of fluids if you have diarrhoea. This is because repeated bouts of diarrhoea can cause you to become

very quickly. Take small, frequent sips of water and drink as much as you can.

For people more vulnerable to the effects of dehydration, such as the elderly, oral rehydration salts may be recommended. Oral rehydration salts are available in sachets from pharmacies. You dissolve them in water and they replace salt, glucose and other important minerals your body loses through dehydration.

Hospital treatment will be required for more serious cases of dehydration because fluids and nutrients will need to be administered intravenously.

Changing your diet

One way to prevent and treat diarrhoea is to make some changes to your diet. Your treatment team may suggest a low-residue diet. This is a diet designed to reduce the amount and frequency of the stools you pass. Alternatively you may be advised to cut down on the amount of fat in your diet.

Foods that can be eaten as part of a low-residue diet include:

  • enriched refined white bread
  • breakfast cereals, such as cornflakes
  • white rice
  • refined pasta
  • noodles
  • cooked vegetables
  • lean meat and fish
  • eggs

You should not make any significant changes to your diet without first consulting your treatment team.


A medicine called loperamide is known to help relieve the symptoms of diarrhoea. It is available over the counter (OTC) at pharmacies and you do not need a prescription to buy it. However, while you are still receiving treatment you should only take loperamide on the advice of your treatment team.

Common side effects of loperamide include constipation and dizziness. Rarer side effects of loperamide include cramps, drowsiness, skin rashes and bloating.

Read more about loperamide in the [diarrhoea medicines guide].


If your symptoms of diarrhoea fail to respond to loperamide, you may be given an alternative medicine called octreotide. Octreotide is a synthetic (man-made) hormone that has proved useful in treating diarrhoea caused by chemotherapy.

Octreotide is usually given twice a day by injection. After receiving treatment, you may experience symptoms of pain, redness and swelling at the site of the injection. These symptoms should pass within 15 minutes.

Side effects of octreotide are uncommon but can include:

  • loss of appetite
  • nausea and vomiting
  • abdominal (tummy) pain
  • flatulence (wind)

Rectal bleeding and ulcers

Some people who have high-dose radiotherapy to treat a cancer in their pelvic region may experience rectal bleeding, as well as inflammation and ulceration of the anus and rectum (proctitis).

If these symptoms become severe, they can be treated using medicines such as cinchocaine hydrochloride (proctosedyl) suppositories or hydrocortisone acetate (colifoam). They are both inserted into your rectum and can help relieve pain and inflammation. They contain both a local anaesthetic to numb the area and a corticosteroid to reduce swelling.

Although there is no conclusive evidence to support its use, a medication called sucralfate can be taken for mucositis that affects the upper gastrointestinal tract, such as ulcers that develop in your stomach or intestines.

Sucralfate is used to create a protective coating over any ulcers. This may help to prevent further damage and speeds up the healing process.

Side effects of sucralfate tend to be mild and short-lasting. They include constipation or diarrhoea, indigestion and nausea.

If you develop a rash or swelling around your face or neck, or shortness of breath, it may indicate you are allergic to sucralfate. If this happens, you should stop taking the medication and contact your treatment team as soon as possible.


Some treatments can be taken before you receive cancer therapy to try to reduce the severity and duration of mucositis.

However, it is rarely possible to completely prevent mucositis from developing after some cancer treatments.

Oral mucositis


Palifermin is often given to people undergoing high-dose

as a preventative measure against oral mucositis.

Read about

treating mucositis
for more information on palifermin.


Benzydamine is a medicine that can be used if you are having low-dose radiotherapy to your head or neck. Benzydamine has been shown to be reasonably effective in reducing the symptoms of inflammation (swelling) and soreness.

Benzydamine is available in the form of a cream, spray and mouth rinse. Your treatment team will be able to advise you about which type of benzydamine is best for you.

You may experience some stinging and numbness of your mouth when you first start using benzydamine, but these side effects should pass in a few days.

Other treatments

There are other treatments that may be used to reduce the severity of oral mucositis and how long it lasts, although some of these have not yet been tested thoroughly. These include:

  • sucking on ice cubes or chips held in the mouth before, during and after cancer treatment
  • honey smeared inside the mouth and slowly swallowed to cover as much mucous membrane as possible
  • aloe vera used as a gel or mouthwash
  • allopurinol mouthwash

A recent study looking into the effectiveness of a medicine called rapamycin suggested it may be a useful treatment for oral mucositis in the future. However, more research is needed before it can be widely used.

Gastrointestinal mucositis


Sulfasalazine is a medicine that can be used to help reduce inflammation of the digestive system in people undergoing radiotherapy to their pelvis.

Sulfasalazine works by blocking some of the body's chemicals involved in the inflammation process.

Occasionally, some people experience an allergic reaction to sulfasalazine. If you experience any allergy-like symptoms, such as a rash, shortness of breath, or swelling of your lips or face, you should stop taking sulfasalazine and contact your treatment team as soon as possible.


Amifostine is a medicine that can be used to help reduce inflammation of the rectum and anus in people who are having radiotherapy for

rectal cancer
. It can also be used to reduce symptoms of a dry mouth in people undergoing radiotherapy for
head and neck cancer

Amifostine helps protect healthy tissue by lowering levels of acid in the body, while also providing additional protection against infection.

However, a recent review of scientific literature reported that evidence for the effectiveness of amifostine when used to treat mucositis was weak.

Side effects can include:

Ranitidine or omeprazole

Ranitidine and omeprazole are medicines that can help relieve stomach and gullet pain in people having chemotherapy. It works by lowering the level of acid in your stomach.

Common side effects of ranitidine include:

  • diarrhoea
  • constipation
  • headache

Complications of mucositis

Oral mucositis and gastrointestinal mucositis can sometimes lead to other problems.

Pain when swallowing

Most people with oral mucositis will experience pain when swallowing. Until your symptoms subside, you may find it easier to switch to a diet that contains softer foods, such as mashed potatoes or puréed scrambled eggs.

Feeding tubes may be required in cases severe enough to place you at risk of becoming

. You will probably be given a nasogastric tube, which is a tube that passes down your nose into your stomach.

The tube can usually be removed after your ulcers heal and your ability to swallow has returned.

Blood poisoning

If you have a weak immune system and a mouth ulcer becomes infected, there is a risk the infection will spread into your blood and organs. This is known as blood poisoning or sepsis.

In the most serious cases of blood poisoning, multiple organ damage can cause a large drop in blood pressure. This is known as septic shock and can be fatal. The symptoms of septic shock include cold skin and an increased heartbeat.

Blood poisoning is a medical emergency and requires immediate treatment in an intensive care unit (ICU) so that the functions of the body can be supported while the infection is treated using antibiotics or antiviral medication.

Read more about

blood poisoning
septic shock

Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.