Diverticular disease and diverticulitis

Diverticular disease and diverticulitis are related digestive conditions. Both affect the large intestine (bowel).

Diverticula are small bulges or pockets that can develop in the lining of the intestine as you get older.

Most people do not get symptoms and only know they have them after having a scan for something else.

When there are no symptoms, it's called diverticulosis. When diverticula cause symptoms, it's called diverticular disease.

If the diverticula become inflamed or infected, it's called diverticulitis. This will cause more severe symptoms.

You're more likely to get diverticular disease and diverticulitis if you do not eat enough fibre.

Symptoms of diverticular disease and diverticulitis

Symptoms of diverticular disease include:

  • tummy pain, usually in your lower left side (periodic pain gets worse when eating or shortly after)
  • emptying your bowels or farting eases tummy pain
  • constipation, diarrhoea or both
  • occasionally, blood in your poo

If your diverticula become infected and inflamed (diverticulitis), you may suddenly:

  • get constant, severe tummy pain
  • have a high temperature
  • have diarrhoea or constipation
  • get mucus or blood in your poo or bleeding from your bottom (rectal bleeding)

When to get medical advice

Contact your GP straight away if you have symptoms of diverticular disease or diverticulitis.

If you've already been diagnosed with diverticular disease, you will not usually need to contact your GP.

Urgent advice: Seek immediate medical advice if:

  • you have any bleeding or severe pain

Contact your GP or, if this is not possible, call your local out-of-hours service.

Tests for diverticular disease and diverticulitis

First, your GP may want to rule out other conditions, such as irritable bowel syndrome (IBS), coeliac disease or bowel cancer.

These often have very similar symptoms to diverticular disease.

This may involve blood tests. If necessary, you'll be referred for a colonoscopy, a CT scan or sometimes both.


A colonoscopy is where a thin tube with a camera at the end is inserted into your bottom and into your bowel.

The doctor will then look for diverticula or signs of diverticulitis. You will be given a laxative beforehand to clear out your bowels.

A colonoscopy should not be painful but can feel uncomfortable.

You may be offered painkillers and a sedative to help you relax and reduce any discomfort.

CT scan

You may need a CT scan. This might be done instead of a colonoscopy or in combination with one. This is called a CT colonoscopy or virtual colonoscopy.

For a CT colonoscopy, the scan is done after you've had the laxative.

Treatment for diverticular disease and diverticulitis

Treatments for diverticular disease


Eating a high-fibre diet may ease symptoms of diverticular disease and stop diverticulitis.

Generally, adults should aim to eat 30g of fibre a day.

Good sources of fibre include fruits and vegetables, beans and pulses, nuts, cereals and starchy foods.

Fibre supplements are available from pharmacists and health food shops. These are usually in the form of powder sachets that you mix with water.

Slowly increase your fibre intake over a few weeks and drink plenty of fluids. This can help prevent side effects linked with a high-fibre diet, such as bloating and wind.


Paracetamol can be used to relieve pain.

Do not take aspirin or ibuprofen regularly as they can cause tummy upsets. Ask a pharmacist about painkillers.

Talk to a GP if paracetamol alone is not working.

You may be prescribed a bulk-forming laxative to ease any constipation or diarrhoea.

Diverticulitis can usually be treated at home with antibiotics prescribed by your GP.

Treatments for diverticulitis


A GP may recommend a fluid-only diet for a few days until your symptoms improve.

While you're recovering you should eat a very low-fibre diet to rest your digestive system.

Once the symptoms have gone, you can return to a higher-fibre diet. Aim to eat about 30g of fibre a day.


Diverticulitis can usually be treated at home with antibiotics prescribed by a GP.

You can take paracetamol to help relieve any pain. Talk to a GP if paracetamol alone is not working.

Do not take aspirin or ibuprofen, as they can cause stomach upsets.

More serious cases of diverticulitis may need hospital treatment.

In hospital, you'll probably get injections of antibiotics, and be kept hydrated and nourished using a tube directly connected to your vein (intravenous drip).

You may also be prescribed a stronger painkiller if paracetamol is not helping.


In rare cases, you may need surgery to treat serious complications of diverticulitis.

Surgery usually involves removing the affected section of your large intestine. This is a colectomy.

A colectomy is a treatment for rare complications such as fistulas, peritonitis or a blockage in your intestines.

After a colectomy, you may need a temporary or permanent colostomy. This is where one end of your bowel is diverted through an opening in your tummy.

The most common complication of diverticulitis is developing abscesses.

These are usually treated by a surgeon or radiologist. They use a technique known as percutaneous drainage.

If you're thinking about surgery, your doctor should explain the benefits and risks.


It's not known why some people get diverticular disease. It seems to be linked to age, diet and lifestyle, and genetics.


As you get older, the walls of your large intestine become weaker. The pressure of hard stools passing through your intestines can cause diverticula.

The majority of people will have some diverticula by the time they are 80 years old.

Diet and lifestyle

It's thought that not eating enough fibre is linked to diverticular disease and diverticulitis.

Fibre helps to make your stools softer and larger, so they put less pressure on the walls of your intestines.

Some other things that seem to increase your risk include:

  • smoking
  • being overweight
  • a history of constipation
  • long-term, regular use of painkillers such as ibuprofen or aspirin

Read our advice on how to eat well


You're more likely to get diverticula disease if a close relative has it. It is even more likely if they developed it before they were 50.

Content supplied by the NHS and adapted for Ireland by the HSE

Page last reviewed: 22 December 2020
Next review due: 22 December 2023

This project has received funding from the Government of Ireland’s Sláintecare Integration Fund 2019 under Grant Agreement Number 123.