Diverticular disease and diverticulitis

Expert reviewer Mrs Sara Badvie, Consultant Laparoscopic, Colorectal and General Surgeon
Next review due September 2021

Diverticular disease is a condition where small pouches, called diverticula, form in the lining of your bowel and push out through the bowel wall, causing symptoms. Symptoms may include, for example, pain in your tummy or a change in bowel habits.

If you have diverticula that don’t cause any symptoms, this is known as diverticulosis.

If your diverticula become inflamed or infected, this is known as diverticulitis and can cause complications.

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About diverticular disease

You could have just a couple or sometimes hundreds of diverticula. They can be tiny or over 2cm wide. Often you won’t know they’re there. You’re more likely to develop diverticula and thus diverticulosis as you get older and the walls of your bowel grow weaker.

The number of people with diverticulosis is increasing. Nearly one in 10 people over 45 have diverticulosis. This may increase to around eight in 10 people by the age of 85. Only around two in 10 people with diverticulosis will go on to develop symptoms and thus diverticular disease at some point.

Causes of diverticular disease

Doctors don’t know exactly why some people develop diverticulosis and potentially go on to be affected by diverticular disease, while others don’t. But it’s thought that there are lots of factors that could be involved – your diet, lifestyle and even your genes may play a part.

Age is one of the main risk factors as outlined above, but your diet is important too.

Having a diet that is low in fibre can affect how well your digestive system works. Your stools (poo) may become hard and more difficult to pass. This creates more pressure inside your bowel and it’s this that is thought to cause diverticula to form and diverticulosis to occur. We think this because vegetarians, and people from parts of the world who have lots of fibre in their diet, appear to be less likely to get diverticulosis and diverticular disease.

However, fibre isn’t the only component of your diet that’s thought to have an effect. Other factors that are thought to increase your risk include:

  • eating red meat
  • drinking alcohol

Smoking and drinking caffeine may also have a role to play, but more evidence is needed. Regardless, stopping smoking and reducing your caffeine intake can benefit your overall health and wellbeing, so try to make positive changes where you can.

Other lifestyle factors that are thought to be involved include being overweight and not getting enough exercise. They may increase your risk of complications and diverticulitis too.

If you’re overweight, learn how to lose weight safely and about having a healthy, balanced diet. If your activity levels could do with a boost, find out how you can get started with exercise too.

Certain types of medicines, such as non-steroidal anti-inflammatory drugs (NSAIDs) may increase your chance of getting diverticular disease. So too can conditions like arterial hypertension and having a weakened immune system.

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Symptoms of diverticular disease

As discussed, if you have diverticula, you might not get any symptoms. This is known as diverticulosis. In fact, only about two out of 10 people with diverticula do.

If you do get symptoms, this is known as diverticular disease. Symptoms may include:

  • recurring pain in your tummy – this may come on when eating and may get better after you go to the toilet or break wind
  • feeling bloated
  • constipation or diarrhoea or a general change in your bowel habits
  • a lot of bleeding or mucus coming out of your rectum (back passage)

Any bleeding may be because blood vessels inside your diverticula have weakened and burst. It is usually painless and doesn’t last long. You might get stomach cramps first.

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. Once you've had symptoms of diverticular disease, you're likely to get them again.

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

Symptoms of diverticulitis can be more severe and include:

  • constant and severe pain in your tummy, usually low down
  • a fever
  • feeling sick or vomiting
  • losing your appetite
  • problems urinating
  • a faster heart rate than normal

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

Diagnosis of diverticular disease

If you don’t have any symptoms, diverticulosis is often spotted when you’re having other tests, like a colonoscopy as part of bowel screening.

If you have symptoms, your GP will ask you about them and examine you. The examination may involve feeling your tummy and inside your rectum for any tenderness or lumps.

They’ll ask you about your medical history, diet and bowel movements. This information can show if you’re likely to develop complications. It also helps your doctor plan the best way to manage your condition.

Diverticular disease is sometimes difficult to diagnose because the symptoms are similar to other conditions. These include irritable bowel syndrome (IBS), appendicitis, gastroenteritis, pelvic inflammatory diseaseurinary tract infections and bowel cancer. In women, symptoms like tummy pain and nausea may be signs of an ovarian cyst or ectopic pregnancy.

Your GP may refer you to see a specialist in bowel conditions (a colorectal surgeon or gastroenterologist). You may need to have one or more of the following tests. These will help rule out other conditions, confirm if you have diverticula and check for complications.

  • A blood test. This can rule out other conditions, and check if bleeding has caused anaemia. It can also show if you have signs of diverticulitis like inflammation or an infection, and how severe any inflammation may be.
  • Computer tomography (CT) scan of your tummy and pelvis. This should show if you’ve got diverticulitis and any complications linked to it. The doctor will first use a tube to pump some air into your rectum. This makes certain complications (like fistulas) show up more clearly on your scan.
  • Ultrasound of your tummy and pelvis. This can be an alternative if you can’t have a CT scan, if you’re pregnant, for instance. Or it can help rule out gynaecological problems and pelvic inflammatory disease.
  • A colonoscopy or sigmoidoscopy. Your doctor will look inside your large bowel to see if you have any diverticula. This will also help to rule out other conditions and identify the source of any bleeding.
  • An X-ray of your tummy. Your doctor may suggest this if they already strongly suspect you’ve got diverticulitis and want to assess any complications.
  • A laparoscopy. This is an exploratory operation, which involves inserting a narrow, tube-like telescopic camera (laparoscope) into your tummy through a small cut. It may be used to treat certain complications and, at the same time, help your doctor to confirm your diagnosis. See our FAQ: Will I need surgery if I have diverticulitis? for more information.

How to help yourself

Adding more fibre to your diet may help to control your symptoms. It can make your bowel movements more regular and encourage the growth of healthy bacteria in your intestine.

There’s still not much evidence, but it’s always a good idea to eat a healthy balanced diet, rich in whole grains, fruits and vegetables.

The recommended amount is about 30g of fibre a day. There’s roughly 8g of fibre in a jacket potato, 2g in an average apple or banana, and 5g in two slices of wholemeal bread.

It’s best to gradually increase how much fibre you eat and build up to that. 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.

Other lifestyle changes, like stopping smoking and losing weight if you’re overweight, may also help manage your symptoms.

Fruit can act as a natural laxative if you have constipation, including apricots, peaches, pears, plums, grapes, raspberries and strawberries.

Go and see your GP if your symptoms don’t improve after a month. They may need to review your diet and do some more tests to check for other conditions.

Treatment of diverticular disease

Your treatment will depend on how severe your symptoms are and the risk of complications.


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 non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and aspirin, because they may cause your diverticula to bleed.

If you have diverticulitis but only a slight inflammation or infection, your GP may prescribe you some antibiotics that you can take at home. Or mild symptoms could clear up on their own.

While you’re taking antibiotics for diverticulitis you might need to stick to a simple low-fibre diet, like white rice. Or your doctor may advise you not to eat anything for a few days and just have clear drinks (especially water) until your symptoms get better. 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.

Your doctor will probably want to see you again after a week to check on your symptoms.

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 heavy bleeding
  • you’re at particular risk of dehydration and can’t drink enough fluids at home. This is generally due to older age and frailty, or conditions like diabetes and cirrhosis

You’ll be given antibiotics and fluids through a drip that’s inserted into a vein in your hand or arm. You may be restricted to certain foods to ‘rest’ your bowels.

Procedures and surgery

Most people with diverticular disease don’t usually need surgery and are able to treat their symptoms at home.

But some complications of diverticulitis may require a surgical procedure, especially to limit the risk of serious infection.

And 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. These include your age and general health, the strength of your immune system, how often symptoms recur and how severe they are.

See our FAQ Will I need surgery if I have diverticulitis? to find out more.

Complications of diverticular disease

If your diverticula become inflamed and infected, this is known as 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. This can cause pain in your pelvic area and around your anus.
  • 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 one of your organs, such as your bladder, a fistula may form. A fistula is a passageway that joins two parts of your body together that aren’t normally connected. Signs of a fistula depend on where it is. You may get frequent urine infections or, in women, vaginal discharge.
  • If your diverticula repeatedly get inflamed, your bowel may get narrower or become blocked. Symptoms include constipation, trapped wind, severe pain, a swollen tummy, and feeling sick.

The risk of developing complications is quite low, and can depend on how quickly any infection in your diverticula spreads. If you have any of these complications, seek urgent medical treatment. You may need further tests.

Prevention of diverticular disease

There are some risks of developing diverticular disease you can’t avoid, like getting older or having certain conditions. But changes to your general health and lifestyle could help reduce your chance of getting diverticular disease, like the ones listed below.

If you’ve had symptoms of diverticular disease once, you’re likely to get them again. But recurrent symptoms shouldn’t increase the risk of complications.

It may help to avoid certain medicines, especially NSAIDs, if possible. This can reduce the risk that your symptoms will return, particularly bleeding, or that you’ll develop complications.

Frequently asked questions

  • Try to eat a diet that contains enough fibre in the form of fruits and vegetables, particularly with the skin left on. This is important for your general health, as well as possibly helping your symptoms.

    Find out how to up your fibre intake.

    In addition to fruit and vegetables, other good sources of fibre are wholegrain foods, beans, peas, nuts and seeds.

    Increase your fibre intake gradually so your digestive system has time to adjust. Drink plenty of fluids at regular intervals to help the fibre do its job properly. You could add pulses like baked beans and lentils to dishes, and extra vegetables to pasta and curry sauces.

    At the same time, you may want to cut down on red meat and foods that are high in sugar and salt. Reducing your caffeine and alcohol consumption might help too. Beer and wine may affect diverticular disease less than spirits and liqueurs.

  • Surgery isn’t recommended very often and you may only need it if symptoms of diverticulitis keep coming back. Or you might need to have an operation if you develop any complications, especially to limit the risk of serious infection spreading.

    Your doctor will talk to you about the pros and cons of having an operation for diverticulitis and what surgery will involve.

    If you have an abscess, you may need a procedure to drain it. This will be done using a thin needle and catheter. The needle and catheter are placed into the abscess through your skin under local anaesthetic and then guided into the correct position using images from a computer tomography (CT) or ultrasound scan.

    If you have diverticulitis and the pockets of diverticula tear, pus can spread to the lining that covers the internal organs in your tummy and cause infection. This is known as peritonitis. If this happens, you’ll need emergency surgery to drain the pus and clean the inside of your abdomen. This is usually done using surgical tools that are passed through small cuts in your abdomen, known as laparoscopy or laparoscopic surgery. You’ll also, at some point, need surgery to remove the damaged part of your bowel. This is known as bowel resection surgery.

    You may also need bowel resection surgery to correct a fistula or part of the bowel that has been obstructed (see our complications section for more information).

    The type of surgery you have will depend on your personal circumstances. If possible, your surgeon will remove the affected part of your bowel and join the remaining healthy parts together. If it isn’t safe for your surgeon to join your bowel back together, because you have a severe infection for example, you’ll need to have stoma surgery. Learn more about having a stoma and stoma care.

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  • Reviewed by Laura Blanks, Specialist Health Editor, September 2018
    Expert reviewer Mrs Sara Badvie, Consultant Laparoscopic, Colorectal and General Surgeon
    Next review due September 2021