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Overview - Diverticular disease and diverticulitis

Diverticular disease, diverticulitis, and diverticulosis are conditions that affect the large bowel (intestine).

Diverticula are small bulges or pockets that can develop in the lining of the bowel as you get older. Most people with diverticula have no symptoms.

Diverticulosis is when is when you have diverticula but have no symptoms. You may only find out you have diverticulosis when you have a scan for something else.

Diverticular disease is when you have diverticula and symptoms.

Diverticulitis is when you have diverticula that become inflamed or infected and you have more severe symptoms.

Symptoms of diverticular disease

The symptoms of diverticular disease include:

  • tummy pain that comes and goes - it is usually in your lower left side and gets worse when eating or shortly after
  • tummy pain that eases when you poo or fart
  • constipation, diarrhoea or both
  • blood in your poo

Symptoms of diverticulitis

Diverticulitis shares most of the symptoms of diverticular disease (listed above).

Other symptoms include:

  • severe tummy pain that does not ease
  • a high temperature
  • feeling sick (nausea) or getting sick (vomiting)
  • feeling unwell

If you have diverticulitis you can get these symptoms suddenly.

The pain usually starts below your belly button and moves to the lower left-hand side of your tummy (abdomen).

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

When to get medical advice

Non-urgent advice: Contact your GP as soon as possible if:

  • you have symptoms of diverticular disease or diverticulitis

If you've already been diagnosed with diverticular disease, you may not need to contact your GP. You can usually treat the symptoms at home.

Non-urgent advice: Ask for an urgent GP appointment if you have:

  • bleeding
  • severe pain

If it is not possible to get a GP appointment, phone your local out-of-hours service.

Causes of diverticular disease and diverticulitis

It is not known why some people develop diverticula. But it is thought to be linked to age, diet and lifestyle, and your genes.


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

Most people will have some diverticula by age 80.

Diet and lifestyle

It's thought that a lack of fibre is linked to diverticular disease and diverticulitis.

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

Other things linked to an increased risk for diverticula include:

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

How to eat well

Your genes

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

Diagnosis and treatment

Page last reviewed: 8 August 2023
Next review due: 8 August 2026