Diverticular disease and diverticulitis

Peer reviewed by Dr Ian Arnott, Consultant Gastroenterologist
Next review due March 2019

Diverticular disease is a condition that affects your large bowel. It happens when small pouches, called diverticula, develop in the lining of your bowel and push out through your bowel wall. In some people, these may cause symptoms such as pain in your tummy but many people don’t get any symptoms.

An image areas of the bowel effected by Diverticular disease

About diverticular disease

Diverticular disease is a common condition – it’s thought to affect up to half of the population of Europe. You’re more likely to get diverticula as you get older. About half of people with diverticula get it by the time they’re 50. This increases to seven in 10 people by the age of 80.

If your diverticula become inflamed and infected, it may lead to a related condition called diverticulitis.

Symptoms of diverticular disease

You might not get any symptoms of diverticular disease. If you do get symptoms, they may include:

  • pain in your tummy, usually on the left-hand side – this may come on when eating and may get better after you go to the toilet
  • feeling bloated
  • constipation or diarrhoea
  • a lot of bleeding or mucus coming out of your rectum (back passage)

If you have any of these symptoms, you should be able to treat them at home. But if they are persistent or you have any bleeding, contact your GP.

Symptoms of diverticulitis can be more severe and include:

  • constant and severe pain in your tummy, usually low-down and on the left-hand side
  • a fever  
  • feeling sick or vomiting
  • losing your appetite

People usually develop diverticular disease on the left-hand side of their bowel so this is where the pain is. But it’s also possible to get it on the right-hand side, particularly if you’re of Asian descent.

If you have any of these symptoms, see your GP.

Diagnosis of diverticular disease

Your GP will ask you about your symptoms and examine you. They’ll ask you about your medical history, diet and bowel movements.

Diverticular disease is sometimes difficult to diagnose because the symptoms are similar to other conditions, such as irritable bowel syndrome (IBS).

Your GP may refer you to see a colorectal surgeon (a doctor who specialises in conditions that affect the bowel). Or they might refer you to see a gastroenterologist – a doctor who specialises in digestive system conditions.

Your GP or doctor may arrange for you to have one or more of the following tests. These will help to confirm if you have diverticula and to check for any complications.

  • A blood test. This can rule out other conditions and also show if you have an infection – a sign of diverticulitis.
  • A colonoscopy. Your doctor will look inside your large bowel to see if you have diverticula (the small pouches that push out of your bowel wall). This will also help to rule out other conditions.
  • CT scan. This should show if you have diverticulitis and any complications linked to it. Unlike a normal CT scan, your doctor will put a tube into your rectum to pump some air up into your rectum. They’ll then take a CT scan.

Treatment of diverticular disease

Your treatment will depend on how severe your symptoms are.


If you start to include more fibre in your diet, particularly from fruit and vegetables rather than cereals, it may help to control your symptoms. There’s not much evidence but it’s always a good idea to eat a healthy balanced diet, rich in whole grains, fruits and vegetables. There’s about 4g of fibre in one wholemeal pitta bread, and almost 4g of fibre in three heaped teaspoons of peas. See Related information to find out more about which foods contain fibre.

It’s best to gradually increase how much fibre you eat and eventually build up to between 18 and 30g each day. If you suddenly increase your intake of fibre, you might pass wind and feel bloated. Drink plenty of fluids because fibre absorbs water.

You may notice an improvement after a few days, but it may take as long as a month for you to feel a difference. If your symptoms don’t improve after this time, go and see your GP. They may need to review your diet and do some more tests to check for other conditions. They may offer you a trial of irritable bowel syndrome (IBS) treatment to rule this out.


Your GP may give you a bulk-forming laxative if you can’t eat a high-fibre diet or have diarrhoea or constipation. This will increase the amount of faeces you have and soften them, so should make it easier for you to go to the toilet.

Your GP may also suggest you take paracetamol to help relieve any pain. It’s best not to take NSAIDs, such as ibuprofen because they may cause your diverticula to bleed.

If you have diverticulitis, your GP may prescribe you some antibiotics for the infection. You might need to hold off food and just have drinks for a few days while you’re taking them, until your symptoms get better. Clear drinks like water are best. You can then gradually introduce solid foods back into your diet.

Always read the patient information leaflet that comes with your medicine. If you have any questions, ask your pharmacist or GP for advice.

Hospital treatment

If you have diverticulitis and it’s severe, you may need to go into hospital if:

  • your symptoms don’t improve after two days of having treatment at home
  • you have a weak immune system
  • paracetamol doesn’t take away your pain
  • you aren’t keeping antibiotic tablets down
  • you have a complication of diverticular disease, such as bleeding

You’ll be given antibiotics and fluids through a drip that’s inserted into a vein in your hand or arm.


You won’t usually need surgery if you have diverticular disease because you can often treat your symptoms at home.

Your doctor might advise you to have surgery if you’ve had symptoms of diverticulitis that keep coming back. But they’ll also take other things into account. For example, you may also need to have surgery if you develop a complication of diverticular disease. See our FAQ Do I need surgery? to find out what’s involved in surgery.

Causes of diverticular disease

Doctors don’t know exactly why people develop diverticular disease but it’s thought that your lifestyle and diet may play a part.

If you don’t eat enough fibre, it can affect how well your digestive system works, and your faeces may become hard. This can make it more difficult for you to empty your bowel, and create more pressure inside your bowel. This pressure might cause the small pouches called diverticula to push through the wall of your large bowel. Diverticular disease seems to be less common in vegetarians, and in parts of the world where people have more fibre in their diet.

Other things that might play a role in diverticular disease include:

  • drinking a lot of alcohol
  • drinking a lot of caffeine
  • certain types of medicines, such as non-steroidal anti-inflammatory drugs (NSAIDs)
  • eating a lot of red meat
  • being overweight
  • not getting enough exercise

Complications of diverticular disease

If your diverticula become inflamed and infected, this may lead to diverticulitis. And this may develop into more serious problems, which are described below.

  • A pus-filled lump, called an abscess, may form on the outside wall of your bowel.
  • If your diverticula are severely infected, they can sometimes burst and cause an infection in your abdomen. This is called peritonitis.
  • If you have an abscess and it bursts into your one of your organs, such as your bladder, a fistula may form. A fistula is a passageway which connects two parts of your body together that aren’t normally connected. You may need an operation to close it.  
  • If your diverticula repeatedly get inflamed, your bowel may get narrower or become blocked. Symptoms include constipation and severe pain, and you may also feel sick.
  • Blood vessels inside your diverticula can weaken and burst, and you’ll bleed from your rectum.

If you have any of these complications, seek urgent medical treatment.

Prevention of diverticular disease

Examples of things you can do to help reduce your chance of getting diverticular disease are listed below.

  • Eat more fibre by eating at least five portions of fresh fruit and vegetables every day. Remember to drink plenty of fluids too.
  • Do some regular exercise.
  • Keep to a healthy weight.

For advice on how to achieve these, see Related topics.

Frequently asked questions

  • Try to eat a diet that contains enough fibre in the form of fruits and vegetables. This is important for your general health, as well as possibly lowering your risk of diverticular disease.

    See our blog ‘Is it time to up your fibre intake?’ to find out more about fibre, as well as which foods it’s in.

    There isn’t much evidence to prove that a high-fibre diet will improve your symptoms but it’s worth a try. You may find it better to eat fibre in the form of fruit and vegetables, rather than having fibre from cereals.

  • You can usually treat diverticulitis at home and won’t need surgery. 

    Surgery isn’t recommended very often and you may only need it if your symptoms of diverticulitis keep coming back. Or you might need to have an operation if you develop any complications.

    If you need an operation, your surgeon will remove the affected part of your bowel and join the remaining healthy parts together. This is known as a colectomy.

    If your surgeon can’t join your bowel back together, because you have a severe infection for example, you’ll need to have stoma surgery. They’ll create a stoma, which is an artificial opening of your bowel on the front of your abdomen (tummy). You’ll have a special bag that will collect your faeces. A stoma can be temporary (and reversed later) but it’s usually permanent if you have emergency surgery. This will depend on which part of your bowel is removed.

    Ask your surgeon what your operation will involve.

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Related information

Tools and calculators

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  • Reviewed by Rachael Mayfield-Blake, Freelance Health Editor, March 2016
    Peer reviewed by Dr Ian Arnott, Consultant Gastroenterologist
    Next review due March 2019

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