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Diverticular disease

Key points

  • Diverticular disease is a common condition that occurs when small pouches called diverticula form in your large bowel.
  • The symptoms of diverticular disease include pain, bloating and constipation.
  • Diverticular disease may be caused by a lack of fibre in your diet.
  • If you’ve been diagnosed with diverticular disease, it may help to increase the amount of fibre you eat.
  • If your diverticula become inflamed and infected, this is known as diverticulitis.

Diverticular disease is a condition that affects your large bowel. It occurs when small pouches, called diverticula, are pushed out through the wall of your large bowel. It’s a common condition that affects up to half of the population of Western Europe and North America.

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

About diverticular disease

Diverticular disease and diverticulitis are related digestive conditions that are caused by diverticula.

Diverticula are small pouches that push through the wall of your large bowel. They can occur if you don’t eat enough fibre.

Diverticular disease is when your diverticula cause you pain in your abdomen (tummy), without inflammation and infection. If your diverticula become inflamed and infected, this is known as diverticulitis.

Your risk of developing diverticula increases as you get older. It’s thought that half of all people have diverticula by the age of 50. This may increase to seven in 10 people by the age of 80.

Symptoms of diverticular disease

If you have diverticular disease, your symptoms may include:

  • lower abdominal pain, usually on the left-hand side
  • bloating
  • constipation
  • diarrhoea
  • bleeding from your rectum (back passage)

The symptoms of diverticulitis may be more severe and include:

  • constant lower abdominal pain, usually on the left-hand side
  • a frequent need to urinate
  • a fever (high temperature)
  • feeling sick or vomiting
  • a loss of appetite

You may develop diverticula on the right-hand side of your large bowel. This is less common than on the left-hand side and is seen more often in Asian patients. Therefore, if you have diverticulitis, your pain may be on the right-hand side of your abdomen.

These symptoms may be caused by problems other than diverticular disease. If you have any of these symptoms, see your GP for advice.

Complications of diverticular disease

Complications are uncommon if you have diverticular disease.

If your diverticula become inflamed and infected, this may lead to diverticulitis. If you have diverticulitis, it may develop into more serious problems. These are explained below.

  • A pus-filled lump, called an abscess, may form on the outside wall of your bowel.
  • Severely infected diverticula 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, for example, your bladder, a fistula may form. A fistula is a passageway that connects two parts of your body together that aren’t normally connected. If you have a fistula, you may need an operation to close it.
  • If your diverticula repeatedly become inflamed, the affected part of your bowel may become narrow or blocked. If this happens you may have constipation and pain, and you may also feel sick.
  • Blood vessels inside your diverticula can weaken and burst causing bleeding from your rectum.

If you have any of these complications, it’s important to get them treated urgently so they don’t cause you more serious problems.

Causes of diverticular disease

Although the reason isn’t clear, it’s thought that lifestyle and diet may play a part in causing diverticular disease.

If you don’t eat enough fibre, your faeces may become pellet-like and hard. This can make it more difficult for you to empty your bowel, creating additional pressure inside your bowel. Small pouches called diverticula, push through the wall of your large bowel.

Diverticular disease may be less common in vegetarians and in parts of the world where people have more fibre in their diet.

Other factors that may cause diverticular disease include:

  • alcohol
  • caffeine
  • certain types of medicines, such as non-steroidal anti-inflammatory drugs (NSAIDs)
  • red meat
  • being overweight
  • lack of exercise


Illustration showing the areas of the bowel commonly affected by diverticular disease

Diagnosis of diverticular disease

Your GP will ask you about your symptoms and examine you. He or she will also ask you about your medical history, diet and bowel movements.

Diverticular disease is sometimes difficult to diagnose because your symptoms may also be similar to other conditions, such as irritable bowel syndrome (IBS).

Your GP may suggest one or more of the following tests to confirm if you have diverticula in your bowel. They may also suggest some of these tests to rule out complications of diverticular disease, such as diverticulitis, and other conditions.

  • A blood test. If your blood test shows that you have a high level of white blood cells or C-reactive proteins, it may be a sign of infection and usually occurs with diverticulitis.
  • A colonoscopy. This is a test that allows your doctor to look inside your large bowel. A colonoscopy is done in hospital using a narrow, flexible, tube-like telescopic camera called a colonoscope. This test can confirm if you have diverticula and rule out other conditions such as bowel cancer.
  • CT scan. This test uses X-rays to make a three-dimensional image of your body or a part of your body. If your symptoms are severe, a CT scan can show if you have diverticulitis and any complications linked to it.
  • A barium enema swallow and meal. This test involves swallowing a fluid containing barium (a substance that shows up on X-rays) into your bowel via your rectum. X-ray images of your abdomen then show the inside of your bowel more clearly. A barium enema X-ray is another way of confirming if you have diverticula. However, this test is not always accurate and will not be performed if you have acute, sudden pain. This is because it may cause your inflamed diverticula to burst (perforate).

Treatment of diverticular disease

Your treatment will depend on the severity of your symptoms and whether or not you have had diverticular disease before.


Your GP may advise you to follow a high-fibre diet (between 18 and 30g each day) to help you control your symptoms. He or she may suggest that you to follow a balanced diet, rich in whole grains, fruits and vegetables.

Your GP will usually suggest that you gradually increase your fibre intake, as a sudden increase can lead to wind and bloating. They may also advise you to drink enough fluids if you increase your fibre intake as fibre absorbs water.

The evidence, however, to suggest whether a high-fibre diet will improve your symptoms is small. You may notice an improvement after a few days, but it may take as long as four weeks for you to feel a difference.

See our FAQ for more information about the types of food you should try and eat if you have diverticular disease.


Your GP may give you a bulk-forming laxative if you’re unable to follow a high-fibre diet or if you have constipation. Bulk-forming laxatives increase the amount of faeces you have and softens them. This may make it easier for you to empty your bowels.

Your GP may also recommend that you take paracetamol to help relieve any pain. You may be advised not to take NSAIDs, such as ibuprofen, as they may cause your diverticula to bleed.

If you have diverticulitis, your GP may prescribe you antibiotics for the infection. They may also advise you to take paracetamol to help relieve any pain. You may also need to follow a fluid-only diet for a few days until your symptoms get better. You can then gradually introduce solid foods back into your diet.

See our FAQ for more information about how diverticulitis is treated.

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


If you have diverticular disease, you won’t usually need surgery because you may be able to successfully treat your symptoms at home.

If you have diverticulitis, your GP may refer you to a colorectal surgeon (a doctor who specialises in conditions that affect the bowel) who may advise that you have surgery. You may have surgery only if you have had symptoms of diverticulitis more than once. You may also need to have surgery if you develop a complication, such as peritonitis, an abscess, fistula or a blockage in your bowel.

See our FAQ for more information about diverticulitis and surgery.

After your treatment

If your symptoms don’t improve after a month of having treatment, it’s important to seek advice from your GP. They may need to review your diet. Your GP may also do more tests to check for other conditions. He or she may offer you a trial of IBS treatment if you have not had this before.

Prevention of diverticular disease

Some examples of what you can do to help reduce your chance of getting diverticular disease are listed below.

  • Increase your fibre intake by eating at least five daily portions of fresh fruit and vegetables. Also include wholegrain foods such as brown rice, pasta and oats in your diet. It’s important to increase your fibre intake slowly to reduce any side-effects, such as excessive wind.
  • If you increase your fibre intake it’s important that you drink enough fluids.
  • Regular exercise, such as running, may help to prevent diverticular disease.

Reviewed by Kuljeet Battoo, Bupa Health Information Team, March 2014.

Find out more about our health editors.

For answers to frequently asked questions on this topic, see FAQs.

For sources and links to further information, see Resources.

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  • This information was published by Bupa's Health Information Team and is based on reputable sources of medical evidence. It has been reviewed by appropriate medical or clinical professionals. Photos are only for illustrative purposes and do not reflect every presentation of a condition. The content is intended only for general information and does not replace the need for personal advice from a qualified health professional. For more details on how we produce our content and its sources, visit the about our health information page.

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