Bowel control problems after pelvic radiotherapy

After pelvic radiotherapy, you may find it difficult to control when and how often you pass poo (stools) or wind.

About bowel control problems

Sometimes pelvic radiotherapy can cause long-term changes to the way the bowel works. After radiotherapy, you may find it difficult to control when and how often you pass stools (poo) or wind. You may sometimes have leakage (bowel incontinence).

Not feeling in control of your bowel can be stressful, particularly when you are away from home. Although you might find it difficult to talk about bowel control problems, it is important to tell your doctor or specialist nurse. There are many things that they can do to help.

Assessing bowel control problems

It is important that you see a doctor so they can properly assess your situation.

Your cancer doctor and their team will probably have helpful suggestions. If your symptoms do not improve, you can ask your GP to refer you to a continence specialist or a specialist in stomach and bowel problems (gastroenterologist).

When you are being assessed, the doctor will usually ask about your bowel problems and things that might affect them. You may also have tests such as blood tests, endoscopy tests (camera tests) or scans.

You might want to keep a record of your bowel habits and what you eat for a week before you go to your appointment. You can use our food and symptom diary to do this. It could help give information about what might help you. At your assessment, the doctor or nurse will usually ask you about:

  • your bowel habits and how they have changed
  • the appearance and consistency of your stools
  • your diet and lifestyle
  • what medicines you take
  • how any change in bowel habit is affecting your day-to-day life.

Treating bowel control problems

The best treatments for bowel control problems depend on your symptoms and what is causing them.


Your doctor or nurse may suggest changing your diet. This can be an important way of improving bowel control. We have more information about diet after pelvic radiotherapy.

Anti-diarrhoea drugs

If you have urgency, loose stools, diarrhoea or bowel incontinence, anti-diarrhoea drugs may help. It is important to speak to a doctor or specialist nurse before taking any medicines.

The most commonly used treatment is loperamide. It slows down your bowel, making the stools more solid and less frequent. Taking loperamide regularly can work very well for some people. It usually works best when taken about 20 to 30 minutes before eating a meal.

It is safe to take loperamide for as long as you need it. But you should discuss this with your doctor.

The dose of loperamide you take may need to be adjusted until you find what works best for you. Your doctor may recommend starting with a low dose and increasing this until it is right for you. Sometimes loperamide can cause cramps. If this happens, it is fine to continue taking it, but at a lower dose. Loperamide is available as a syrup, which allows you to adjust the dose as needed.

Sometimes doctors prescribe other types of anti-diarrhoea medicine, such as codeine phosphate or diphenoxylate (Lomotil®). Your doctor or a continence adviser can advise you about the medicines that may be best for you.

Drugs that make bowel symptoms worse

You may be taking medicines that can make bowel symptoms worse.

Medicines that can increase bloating, wind, urgency or loose stools include:

  • non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and diclofenac
  • magnesium in antacids (for heartburn)
  • proton pump inhibitors such as omeprazole (Losec®)
  • Lactulose® and Fybogel®
  • metformin – a tablet used to treat diabetes
  • beta-blockers – tablets to treat high blood pressure and some heart problems
  • antibiotics
  • some types of anti-depressants such as venlafaxine and citalopram.

If you are taking any of these drugs, and think they may be making your symptoms worse, tell your doctor. They may be able to prescribe a different drug that may affect you less.

Smoking or vaping and bowel control

If you have problems with urgency, loose stools or bowel incontinence, smoking or vaping can make things worse. This is because nicotine stimulates the bowel. Talk to your doctor about ways to give up or cut back. We have more information about giving up smoking.

Strengthening the muscles used for bowel control

Exercises to strengthen the muscles used in bowel control are called pelvic floor exercises. They may help with:

  • urgency
  • bowel incontinence
  • difficulty emptying your bowel completely
  • wind.

We have more information about pelvic floor exercises.

Bowel retraining

Bowel retraining can help you to get your bowel habits back into a regular pattern. This means setting a regular time to empty your bowels.

If you have loose stools or urgency, you may worry you will not be able to ‘hold on’. Worrying you may not get to the toilet in time can make you anxious. You may try to monitor your bowel for signs that you need to go to the toilet. This can make you aware of any activity in your bowel, including wind.

Continence specialists can teach you to retrain your bowel. The aim is to help you build up the length of time you can ‘hold on’. Bowel retraining is often used with other methods such as anti-diarrhoea medicines and muscle-strengthening exercises.

With bowel retraining, you learn to resist the urge to go straight away. At first, you start by getting to a toilet when you feel the urge. You then wait for a minute or so before sitting on the toilet to empty your bowels. The aim is to increase the time between feeling the urge to go and emptying your bowel. This will build up your confidence and give you more control of your bowel.

Good toilet habits for bowel control

Learning good toilet habits can help with problems such as constipation or straining on the toilet. We have more information about good toilet habits for bowel control.

If you have ongoing diarrhoea

If changing your diet and taking anti-diarrhoea drugs does not stop the diarrhoea, ask your doctor to refer you to a gastroenterologist. Lots of different things can cause diarrhoea, and a gastroenterologist will be able to do a full assessment.

After pelvic radiotherapy, some people have diarrhoea or pale, smelly stools that are difficult to flush away. This can be caused by the following conditions.

Bile acid malabsorption (bile acid diarrhoea)

Bile acids are made in the liver and go to the small bowel to help us digest fats. They are then absorbed into the small bowel. Sometimes radiotherapy damages the small bowel and it cannot re-absorb the bile acids. This is called bile acid malabsorption (BAM). It can cause bouts of watery diarrhoea, abdominal cramping and bloating. These can be related to the amount of fat eaten in the past 24 hours.

A bowel specialist can diagnose bile acid malabsorption using a SeHCAT scan. They will explain this test to you if you need it.

If you have bile acid malabsorption, they may advise you to follow a low-fat diet. A dietitian will be able to help you do this in a balanced way.


The drug most commonly used to treat bile acid malabsorption is colestyramine (Questran®, Questran Light®). It is a powder that you mix with water or fruit juice.

If colestyramine does not work, your specialist may prescribe a different medicine, called colesevelam (Cholestagel®). You take it as a tablet.

Most people with bile acid malabsorption do not absorb enough vitamins and need to take vitamin supplements. Your doctor can talk to your more about this.

Small bowel bacterial overgrowth

A healthy small bowel contains almost no bacteria. But the large bowel contains lots of healthy or ‘good’ bacteria, which help us digest food. After pelvic radiotherapy, sometimes bacteria can be found in the small bowel. This can cause different symptoms, including:

  • diarrhoea
  • wind
  • bloating
  • constipation
  • feeling sick
  • vomiting
  • bad breath.

A breath test can help to find out whether you have small bowel bacterial overgrowth. You can have the test as an outpatient. Samples of your breath are tested. This tells the doctors if there are bacteria in your small bowel.

Small bowel bacterial overgrowth is usually treated with antibiotics.

Exocrine pancreatic insufficiency (EPI)

This condition sometimes develops in people who have had pelvic radiotherapy that includes para-aortic lymph nodes, which are close to the pancreas. This type of radiotherapy is sometimes used to treat cervical cancer or womb cancer.

The pancreas makes proteins called enzymes that help to digest food. Exocrine pancreatic insufficiency develops when the pancreas does not make enough enzymes to digest food properly.

Supplements to replace the enzymes

If your doctor thinks you might have EPI, they can arrange for you to have a stool test (faecal elastase test) to find out. If you have EPI, you will need a supplement to replace the enzymes. There are several different brands available. Most supplements are made from pigs. It is also possible to get supplements made from beef. Vegetarian-based enzymes are not available.

The most commonly used supplement is a tablet called Creon, which is a pork-based enzyme replacement. There is no alternative that is not pork-based. Jewish and Muslim organisations support its use if there is no alternative. If you have concerns speak to your doctor or nurse.

You will need to take this with everything you eat or drink. You usually take the capsules for the rest of your life.

Most people with pancreatic insufficiency do not absorb enough vitamins and minerals. You may also need a multi-vitamin and mineral supplements. A dietitian will be able to help you use the tablets correctly, as it is important to take enough of the supplements.