Diverticular disease and diverticulitis

Diverticular disease and diverticulitis are related conditions that affect the large intestine (colon). The large intestine is the final processing area for digested food.

About diverticula, diverticular disease and diverticulitis

Below are descriptions of the related conditions and their medical names.


These are pouches (small bulges) that push through the muscular wall of the colon. The exact reason why diverticula develop is not known but they are associated with not eating enough fibre.

Diverticula are common and associated with getting older. The large intestine (colon) becomes weaker with age. The pressure of hard stools (poo) passing through the large intestine is thought to cause the pouches to form.


This occurs when diverticula (pouches) are present without symptoms. Most people with diverticula will not have any symptoms.

Diverticular disease 

This occurs when diverticula (pouches) cause intermittent lower abdominal (stomach) pain


This occurs when diverticula (pouches) become inflamed and infected causing significant lower abdominal pain. It is thought an infection develops when a hard piece of stool or undigested food gets trapped in one of the pouches. This gives bacteria in the stool the chance to multiply and spread, triggering an infection.

Symptoms of diverticular disease 

One in four people who develop diverticula will experience symptoms.

Symptoms of diverticular disease include:

  •  Intermittent (stop-start) pain in your lower abdomen below the umbilicus (belly button), and feeling bloated. The pain may be in the midline, but may be to one side, depending on the severity of the symptoms/complications. If it moves to one side of your lower abdomen this will usually be in the lower left-hand side; but not always.

Other long-term symptoms of diverticular disease include:

  • a change in your normal bowel habits, such as constipation or diarrhoea, or episodes of constipation that are followed by diarrhoea
  • bloating

Diverticular disease does not cause weight loss, so if you are losing weight, seeing blood in your stools or experiencing frequent bowel changes, see your GP.

Symptoms of diverticulitis 

Diverticulitis shares most of the symptoms of diverticular disease (see above). However, the pain associated with diverticulitis is constant and severe, rather than intermittent. It is most likely to occur if you have previously had symptoms of diverticular disease, and develops over a day or two.

Other symptoms of diverticulitis can include:

The pain usually starts below your belly button, before moving to the lower left-hand side of your abdomen.

In Asian people, the pain may move to the lower right-hand side of your abdomen. This is because East Asian people tend to develop diverticula in a different part of their colon for genetic reasons.

Treating diverticular disease and diverticulitis 

A high-fibre diet can often ease symptoms of diverticular disease, and paracetamol can be used to relieve pain.

Other painkillers such as aspirin or ibuprofen are not recommended for regular use for the pain associated with diverticular disease, as they can cause stomach upsets, or promote bleeding from the large bowel when this condition is present.

Speak to your GP if paracetamol alone is not working.

Mild diverticulitis can usually be treated at home with paracetamol, clear fluids and antibiotics prescribed by your GP. More serious cases may need hospital treatment to prevent and treat complications.

Surgery to remove the affected section of the intestine is sometimes recommended if there have been serious complications, although this is rare.

When to seek medical advice 

Contact your GP as soon as possible if you think you have symptoms of diverticulitis.

If you have symptoms of diverticular disease and the condition has previously been diagnosed, you do not usually need to contact your GP as the symptoms can be treated at home.

If you have not been diagnosed with the condition, contact your GP so they can rule out other conditions with similar symptoms, such as appendicitis and colitis.

Causes of diverticular disease and diverticulitis 

The exact reason why small bulges in the large intestine (diverticula) develop is not known, but they are associated with not eating enough fibre.

It is not known why only one in four people with diverticula go on to have symptoms of diverticulitis.

Diverticular disease may be chronic low-level diverticulitis. The symptoms can be similar to irritable bowel syndrome (IBS) and may overlap.

Preventing diverticular disease and diverticulitis 

Eating a high-fibre diet may help prevent diverticular disease, and should improve your symptoms.  Your diet should be balanced and include at least five portions of fruit and vegetables a day, plus whole grains. 


The information on this page has been adapted from original content from the NHS website.

For further information see terms and conditions.

This page was reviewed May 2018

This page is due for review January 2021

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