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Page last reviewed: 13/07/2011

Mucositis is a condition that causes pain and inflammation of the surface of the mucous membrane. The mucous membrane is the soft layer of tissue that lines the digestive system including the:

  • mouth
  • stomach
  • anus (back passage)

Mucositis develops as a side effect of radiotherapy and chemotherapy. The radiation used during radiotherapy and the powerful cancer-killing medicines used in chemotherapy can damage the cells of the mucous membrane.

However, in radiotherapy, mucositis will only occur if the high-energy beams of radiation are directed at the areas of the body where the mucous membrane is present, such as the mouth and oesophagus (the passageway that connects the mouth to the stomach). Therefore, patients who are receiving radiotherapy for other types of cancer, such as breast cancer, will not usually develop mucositis.

Types of mucositis

There are two types of mucositis:

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

How common is mucositis?

Mucositis can be a very common side effect of certain types of cancer treatment. For example, four out of ten people who have chemotherapy as part of their cancer treatment will develop some degree of mucositis.

Mucositis is more common among certain types of cancer. For example, one in three people who have radiotherapy or chemotherapy for head or neck cancers will develop mouth problems, such as oral mucositis.

At least three-quarters of people who receive high-dose chemotherapy because they are undergoing a stem cell transplant (more commonly bone marrow transplant) known as a will develop oral mucositis.

Radiation-induced mucositis is less common in cancer treatments that do not involve the head or neck, but it can still be a problem.


Oral mucositis can be very painful, but the ulcers that are caused by the condition will heal without treatment and will not leave scars.

The symptoms of mucositis should begin to improve three or four weeks after chemotherapy or radiotherapy has finished. However, if you have had radiotherapy that is aimed directly at your mouth, it may take six to eight weeks before your symptoms start to improve.

The most serious cases of mucositis can lead to a number of associated health complications, some of which are occasionally life-threatening. Therefore, the condition requires careful management and monitoring.

Many people with mucositis find it painful to swallow food and require alternative feeding methods, such as a feeding tube. A lack of suitable nutrition, combined with the symptoms of diarrhoea, can quickly cause a person to become malnourished and dehydrated.

Sometimes, mouth ulcers can become infected with bacteria. In people with a weakened immune system (as is usually the case in those receiving high-dose chemotherapy or radiotherapy) the infection can spread to the blood and then on to other organs. This is known as sepsis and it can be a life-threatening condition that requires emergency treatment.

Preventing mucositis can often be difficult. However, treatments are available that can shorten the duration of the condition and reduce the severity of its symptoms. See Mucositis - treatment and Mucositis - prevention for more information.

Immune system
The immune system is the body's defence system, which helps protect it from disease, bacteria and viruses.
Inflammation is the body's response to infection, irritation or injury. It causes redness, swelling, pain and sometimes a feeling of heat in the affected area.

Page last reviewed: 13/07/2011

Oral mucositis

The symptoms of oral mucositis usually begin five to ten days after starting  or 14 days after starting radiotherapy and chemotherapy

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 that you will develop ulcers on the lining of your mouth and, in some cases, on your tongue and on or 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.

The symptoms of oral mucositis should stop three to four weeks after your course of chemotherapy or radiotherapy has finished. However, it can take longer (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
  • blood in your stools
  • abdominal pain
  • difficulty swallowing (dysphagia)
  • 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.

Page last reviewed: 13/07/2011

Mucositis is usually a side effect of cancer treatment.

Radiotherapy and chemotherapy

Radiotherapy and chemotherapy are very effective treatments for killing cancer cells but they can also damage healthy cells, particularly the 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, including your mouth, stomach and anus (back passage).

Radiotherapy and chemotherapy damage the DNA of the cells on the lining of your mucous membrane. DNA is a long molecule made of two coiled strands, which stores genetic information.

The damaged cells release small toxic molecules (known as reactive oxygen species) which, in turn, cause further damage to nearby cells. These damaged cells then release more toxic substances. This means that any initial damage can quickly spread and attack the tissue of the mucous membrane.

Eventually, the layer of tissue that lines your mucous membrane will break down and ulcers (sores) will form. Your cancer treatment team will make every effort to limit the damage to your mucous membrane, although 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.

There are several different types of biological therapy, which work in different ways. For example, some cancers use a type of protein called mTOR to help the cancer cells grow. A biological therapy called an mTOR inhibitor can be used to stop these cancers growing.

Some people being treated with mTOR inhibitors have developed mouth ulcers. They are thought to be different from the usual mucositis caused by radiotherapy or chemotherapy, although at the moment they are poorly understood.  

Risk factors

Some factors 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 younger people 
  • 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
  • undergoing a stem cell transplant (bone marrow transplant)

To prepare for a stem cell transplant, any cancer cells are killed using high-dose chemotherapy and sometimes radiotherapy. The treatment also stops your immune system (the body's natural defence against infection and illness) from working, so that your body does not reject the transplant. Damage to the mucous membrane is a side effect of both of these types of treatment.

Page last reviewed: 13/07/2011

Oral mucositis

If you are receiving high-dose radiotherapy and chemotherapy ,it is likely that you will receive a regular (weekly) assessment 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 that 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 you 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 that you can be given nutritional support and your general health can be carefully monitored. See Mucositis - treatment for more information.

Gastrointestinal mucositis

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

Occasionally, 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:

  • ultrasound scan,
  • an  which is a procedure that uses high frequency sound waves to create an image of part of the inside of your body
  • computerised tomography (CT) scan,which is where several 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

Page last reviewed: 13/07/2011

Oral mucositis

Self care

If you have oral mucositis, it is very important that you have a good oral hygiene routine because it can reduce the severity of your symptoms and shorten the length of time that you have them for.

Below is some general advice to help you obtain a good level of oral hygiene. 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.
  • Allow the toothbrush to dry before storing it. 
  • 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 that is 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. However, if you have diarrhoea, you will need to drink more than this to avoid becoming dehydrated.

Ice cubes

In the past, sucking ice cubes or ice chips was often recommended as a way of providing relief from the symptoms of oral mucositis. However, sucking ice cubes can cause your blood vessels to narrow, which may result in the chemotherapy or radiotherapy not reaching the tissues that they are supposed to be treating. In some cases, ice cubes may also cause more damage to the lining of your mouth. 

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

You will usually be started on a simple painkiller, such as paracetamol. If this proves ineffective at controlling your pain, 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. 

If you are in severe pain, you can be given morphine by a continuous drip through a narrow tube into a vein in your arm.

Non-steroidal anti-inflammatory drugs (NSAIDs) may provide pain relief for some people. However, if you are receiving platinum-based 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 reasonably successful in treating people who are having a stem cell transplant (bone marrow transplant) and who are thought to be at considerable risk of developing oral mucositis.

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 it can be used to prevent, as well as treat, mucositis.

One small study found that people taking a single dose of palifermin before their chemotherapy also experienced less nausea and constipation than those who did not. 

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 your tongue
  • general swelling of the body
  • pain
  • fever
  • 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.

The use of palifermin during pregnancy is not recommended. This is because there has not been any testing to determine whether palifermin is safe to use during pregnancy. Therefore, you should tell your treatment team if:

  • you are pregnant
  • you think that you are pregnant
  • you plan to get pregnant

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. 

Gastrointestinal mucositis

Treatments for diarrhoea

It is very important that you drink plenty of fluids if you have diarrhoea. This is because repeated bouts of diarrhoea can cause you to become dehydrated very quickly. Take small, frequent sips of water and drink as much as you can.

For people who are 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 that your body loses through dehydration.

If you have a kidney condition, certain types of oral rehydration salts may not be suitable for you. Ask your pharmacist or GP for advice about this.

Hospital treatment will be required for more serious cases of dehydration because fluids and nutrients will need to be administered intravenously (directly into a vein).

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 that is designed to reduce the amount and frequency of the stools that you pass.

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.

Loperamide is not suitable for people with colitis (inflammation of the colon) or pregnant women. However, it can be used safely by breastfeeding women.


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 (intravenously). 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 (feeling sick)
  • vomiting (being sick)
  • abdominal (tummy) pain
  • flatulence (wind)
  • changes in blood sugar levels

The side effects of octreotide can be minimised by injecting the medication between meals or before bed.

Rectal bleeding and ulcers

Some people who have high-dose radiotherapy to treat a cancer that is in their pelvic region may experience inflammation and ulceration of the anus and rectum and rectal bleeding. Proctitis is a medical term that is used to describe inflammation of the lining of the rectum (the lower section of the large bowel).

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

Colifoam also contains a corticosteroid to hep reduce inflammation and is a foam that is inserted into your rectum once or twice a day. Your treatment team will explain how to use colifoam or the patient information leaflet that comes with the medication will provide details.

If ulcers and inflammation affect your digestive system higher up, they can be treated using a medicine called sucralfate. Sucralfate works by creating a protective coating over any ulcers. This helps to prevent further damage and speeds up the healing process. Sucralfate can be taken for mucositis that affects the upper gastrointestinal tract, such as ulcers that develop in your stomach or intestines.

Side effects of sucralfate tend to be mild and short-lasting. They include:

  • constipation or diarrhoea
  • indigestion
  • nausea
  • dry mouth
  • headache
  • itching

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


If your mouth is sore because of radiotherapy or chemotherapy , you may need to change your eating habits. The following tips may help you to avoid making your symptoms worse:

  • eat moist or soft food because dry food may scratch your mouth
  • eat plain food and avoid spicy flavours
  • eat warm rather than hot food

If you are unable to eat or drink because of mucositis, you may need to be admitted to hospital so that you can receive nutrition in one of the following ways.

  • with a nasogastric feeding tube: where a tube is inserted into your nose and down into your stomach 
  • with a gastrostomy: where a tube is inserted directly into your stomach 
  • intravenously: where a tube is inserted directly into a vein

Page last reviewed: 13/07/2011

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 pureed scrambled eggs.

Feeding tubes may be required in cases that are severe enough to place you at risk of becoming malnourished and dehydrated. 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 that becomes infected, there is a risk that 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 it 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.

See the Health A-Z topics about Blood poisoning and  Septic shock for more information about these conditions.

Immune system
The immune system is the body's defence system, which helps protect it from disease, bacteria and viruses.

Page last reviewed: 13/07/2011

It is not usually possible to prevent mucositis from developing following a course of radiotherapy or chemotherapy.However, there are several treatments that can be used to help reduce the severity and duration of your symptoms.

Oral mucositis


As discussed in Mucositis - treatment, palifermin is often given to people who are undergoing high-dose chemotherapy or radiotherapy, as a preventative measure against oral mucositis.


Benzydamine is a medicine that can be used if you are having 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.

Gastrointestinal mucositis


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

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

Occasionally, some people experience an allergic reaction to sulfasalazine. If you experience any allergic-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 inflammation of the windpipe in people who are undergoing chemotherapy or radiotherapy for lung cancer.

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

Side effects include:

  • nausea (feeling sick)
  • vomiting (being sick)
  • hiccups 
  • low blood pressure (hypotension)


Ranitidine is a medicine that can help reduce inflammation of the stomach and relieve the symptoms of stomach pain in people who are having chemotherapy. It works by lowering the levels of acid in your stomach.

Common side effects of ranitidine include:

  • diarrhoea
  • headache
  • dizziness
  • nausea
  • skin rash
  • tiredness
Inflammation is the body's response to infection, irritation or injury, which causes redness, swelling, pain and sometimes a feeling of heat in the affected area.

Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.

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