You might need to change what you eat after treatment for bowel cancer.

Bowel changes

You will find that your digestion takes time to settle down after bowel cancer treatment. Some foods can upset the way your bowel works. After treatment, high fibre foods, such as fruit and vegetables, may give you loose poo. You may need to go to the toilet much more often than normal.

If you have had a colostomy you may find that it takes a few months for your bowel to work normally again. If you have had a combination of treatments, you may have permanent changes to your bowel. You may need to avoid certain foods.

Some foods can cause wind, which will go into your stoma bag if you have a colostomy or ileostomy.

You may need to experiment a bit to find out which foods upset your system. The foods most likely to cause problems are:

  • very high fibre fruits and vegetables
  • onions, brussel sprouts and cabbage
  • pulses such as baked beans or lentils
  • fizzy drinks, beer and lager
  • very rich or fatty foods

Eating after surgery

When you are well enough to go home after your operation, you will be eating fairly normally. You may be on a low fibre diet for about 6 weeks. You can then gradually increase the amount of fibre in your diet.

The large bowel (colon) normally absorbs water as the poo passes through it.  So if you have had part of your large bowel removed, your poo may become less solid. If you have had a large part of it removed, you may have diarrhoea.

Let your doctor or nurse know if this happens, as they can give you medicine to help control it. It is important to drink plenty of fluids if you have diarrhoea. If you are drinking a lot and still feel thirsty you may need to have a drink that replaces fluid and body salts (an electrolyte replacement drink). Your doctor can advise you about this.

Your bowel should start to work more normally after a few weeks. But particular foods may upset things. You may need to experiment with your diet to find out which foods cause a problem for you.

As the bowel settles down you may find that you can start to eat these foods again later on. Everyone is different and there are no set rules about what you should eat. If you have problems you can ask to see a dietitian at the hospital. They can give you tips and help you to work out which foods upset you.

Keep a food diary

It can help to keep a food diary before you go to see the dietitian. The diary is a record of:

  • what you eat
  • when you eat
  • any digestive problems and when you have them

Looking back over a weekly diary you may be able to spot which foods are causing you problems and then cut them out. You may be able to try the food again in a few weeks to see if it causes the same problem.


  • Eat foods high in calories and protein to help with healing and fighting infection. High protein foods include meat, fish and eggs.
  • Eat small, more frequent meals to begin with rather than 3 large meals a day. Try to avoid long gaps between meals.
  • It may help to eat a low fibre diet at first. Examples of low fibre foods are white pasta and bread, cream crackers, rich tea biscuits, cornflakes, and vegetables and fruit that are well cooked and peeled.
  • Drink plenty of fluids - at least 3 to 4 pints or 1.5 to 2 litres a day.
  • Reduce the amount of caffeine you have in a day. Caffeine can stimulate the bowel and make diarrhoea worse.
  • Take small mouthfuls and chew your food slowly.
  • Drinking peppermint water may help relieve trapped wind and so ease discomfort.

Eating after radiotherapy

Radiotherapy to the bowel often causes diarrhoea. This can take a few weeks to settle down after the treatment ends. Your doctor can give you tablets to help control the diarrhoea. If it doesn't improve within 4 to 6 weeks of finishing your treatment, let your doctor know.

While you are getting over your treatment it is best to keep taking the diarrhoea medicines. You can gradually reduce the amount you take. Your doctor or nurse will advise you about how to manage this.

Eating after chemotherapy

Chemotherapy for bowel cancer can give you diarrhoea and may make you feel sick. You may also have a sore mouth. These side effects will disappear after your treatment is over. You can gradually get back to a normal diet.

Get help

Dietitians can help you cope with eating problems and suggest ways of dealing with diet difficulties. Ask your doctor or nurse to refer you.

A dietitian can support you with diet problems from diagnosis, through treatment and afterwards.

Eating problems can be difficult to cope with. They can cause tension within relationships or families. Events and eating out with friends can be much harder when you have bowel problems. Talking to your dietitian or a counsellor can help.

Regaining weight can be more difficult than maintaining it. It is important to get help as soon as you start to have problems.

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