What is diverticular disease?
Diverticular disease describes small pouches (diverticula) that form at weak points in the wall of the large bowel, most often the sigmoid colon on the lower left side. Many people have pouches with no symptoms at all (diverticulosis); others get intermittent cramping, bloating and altered bowel habit. When a pouch becomes inflamed or infected, the result is diverticulitis, causing significant pain and fever.
Diverticula become increasingly common with age, affecting the majority of people over 70 to some degree, and are linked to low-fibre Western diets, obesity and inactivity. They are often discovered incidentally during colonoscopy or CT scans done for other reasons. Symptomatic disease is diagnosed with a CT scan during acute attacks, or colonoscopy once inflammation has settled, partly to exclude other causes.
Common symptoms
- Intermittent cramping pain, typically in the lower left abdomen
- Bloating and excess wind
- Constipation, diarrhoea or an erratic bowel habit
- Constant severe left-sided pain with fever during diverticulitis
- Nausea during acute attacks
- Rectal bleeding, occasionally brisk
- Tenderness over the lower abdomen
How long will you wait?
Routine NHS colonoscopy to assess diverticular disease commonly takes two to four months, and where elective surgery is recommended after recurrent attacks, waits of four to nine months are common at many trusts.
Privately, you can typically see a consultant within 3–7 days, with colonoscopy or CT usually within 1–2 weeks and elective surgery, if needed, within 2–6 weeks.
NHS England median referral-to-treatment wait: 12.4 weeks, with 2.5 million people waiting over 18 weeks (May 2026). Individual waits vary by trust and urgency.
Treatment options
- High-fibre diet and lifestyle. Gradually increased fibre, good hydration, exercise and weight management reduce symptoms and the risk of attacks.
- Treatment of acute diverticulitis. Mild attacks are managed with rest, fluids and sometimes antibiotics; severe attacks need hospital care.
- Elective sigmoid colectomy. Keyhole removal of the affected bowel segment is considered after repeated or complicated attacks.
- Emergency surgery. Reserved for perforation, abscess or obstruction, occasionally requiring a temporary stoma.
What does private treatment cost?
As a guide, a private colonoscopy typically costs around £1,800–£2,800, and elective laparoscopic sigmoid colectomy typically around £10,000–£14,000 in the UK in 2026.
Does health insurance cover diverticular disease?
Acute episodes of diverticulitis arising after your policy starts, including scans, hospital admission and surgery for complications, are usually covered by private medical insurance. Diverticular disease diagnosed or symptomatic before you joined will typically be excluded as pre-existing at first. Because mild diverticular symptoms can grumble on long term, insurers may treat routine dietary management and surveillance as ongoing care they do not fund, while still covering genuinely acute flare-ups.
Frequently asked questions
I have been told I have diverticula. Should I be worried?
Usually not. Diverticulosis, pouches without symptoms, is close to a normal feature of the ageing bowel and needs no treatment beyond a sensible high-fibre diet. Only a minority of people ever develop significant symptoms, and a smaller minority still have attacks of diverticulitis. The pouches are not precancerous, and having them does not change your bowel cancer screening requirements.
Do I need to avoid nuts, seeds and sweetcorn?
No. The old advice that seeds and nuts lodge in diverticula and trigger attacks has not stood up to scrutiny; large observational studies have found no increased risk, and nuts and seeds are valuable fibre sources. Current guidance encourages a varied, high-fibre diet with plenty of fluid. During an acute attack of diverticulitis, however, a temporarily low-residue diet may be advised until things settle.
When is surgery recommended for diverticular disease?
Emergency surgery is needed for the small proportion of attacks complicated by perforation, abscess or obstruction. Planned surgery is considered case by case, typically after recurrent significant attacks, a persistent narrowing or fistula, or attacks that keep interrupting life and work. Modern practice is more conservative than it once was, as many people have no further trouble after a first uncomplicated episode.
Related guides
- Acid Reflux (GORD)
- Barrett's Oesophagus
- Coeliac Disease
- Crohn's Disease
- Irritable Bowel Syndrome (IBS)
- Ulcerative Colitis