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Health condition · Clinically reviewed

Diverticular disease, from silent pouches to acute flares - and the plan for each.

Most people with diverticula never notice them. When symptoms appear, a CT-led plan and a few steady lifestyle changes usually settle things without surgery.

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Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against NICE NG147, BSG and peer-reviewed sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK practice including selective antibiotic use, CT-led staging and elective laparoscopic surgery.

Key facts

Diverticular disease at a glance.

The essentials, in plain English - what it is, who gets it, and how it is treated in the UK today.

  • What it is

    Small pouches (diverticula) pushing through the wall of the colon, most often the sigmoid, that can inflame, bleed or perforate.

  • How common

    Very common with age - present in up to half of people over 60 and around 70 per cent over 80 in Western countries.

  • The spectrum

    Asymptomatic diverticulosis, symptomatic uncomplicated disease (SUDD), acute diverticulitis and complicated diverticulitis.

  • The main drivers

    A low-fibre Western diet, chronic constipation, obesity, smoking, red meat and regular NSAID use, layered on genetic and microbiome factors.

  • Foundation of care

    Fibre, fluids, weight and exercise - simple lifestyle changes that reduce flares and complications.

  • When it turns serious

    Perforation, abscess, peritonitis, fistula, obstruction or brisk lower-GI bleeding - all reasons to escalate quickly.

Why this guide matters

A staged plan, not a one-size-fits-all approach.

Diverticular disease is common, and the right plan depends on where you sit on the spectrum. The three points below shape everything else on this page.

  • Lifestyle is the foundation

    Fibre, fluids, weight, exercise and stopping smoking do more than any single medicine to reduce flares.

  • Antibiotics are increasingly selective

    Modern guidance supports withholding antibiotics in mild uncomplicated flares in carefully chosen patients.

  • Surgery is reserved for complications

    Perforation, abscess, fistula, obstruction or quality-of-life-limiting recurrence - not a first-line option.

How the diagnosis is made

From first symptoms to a clear plan.

The steps a UK GP, gastroenterologist or colorectal surgeon will typically follow, in order - so you know what to expect and why.

  1. 01

    Assessing

    History and examination

    Left lower quadrant pain, altered bowel habit, fever and tenderness - the pattern that first raises the possibility of diverticular disease.

  2. 02

    Assessing

    Bloods - FBC, CRP, U&Es

    Inflammatory markers and kidney function help gauge severity and readiness for imaging or contrast.

  3. 03

    Assessing

    Rule out other causes

    Colorectal cancer, IBS, IBD, gynaecological pain and urinary infection all overlap - a careful sift matters.

  4. 04

    Confirming

    CT abdomen and pelvis with contrast

    The gold standard in acute diverticulitis - stages disease using the Hinchey classification (I to IV) and finds abscess or perforation.

  5. 05

    Confirming

    Colonoscopy after recovery

    Six to eight weeks after an acute episode to confirm the diagnosis and exclude an underlying cancer.

  6. 06

    Confirming

    Selective flexible sigmoidoscopy

    Where a full colonoscopy is not needed - a focused look at the sigmoid where most diverticula sit.

  7. 07

    Planning

    MRI or CT enterography for fistula

    When colovaginal or colovesical fistula is suspected - recurrent UTI, pneumaturia or faecaluria are the clues.

Typical pathway: from GP review to CT-led staging within days in an acute flare.

Symptoms

What diverticular disease actually feels like.

The classic pattern of left-sided pain, altered bowel habit and, at times, bleeding - and the features that mean it is time to escalate.

  • Left lower quadrant pain

    A dull, crampy ache in the left iliac fossa is the classic pattern, often relieved by passing wind or stool.

  • Bloating and altered bowel habit

    Constipation, diarrhoea or a swing between the two - typical of symptomatic uncomplicated disease.

  • Fever and tenderness

    A rising temperature with focal tenderness and guarding suggests acute diverticulitis, not simple pouches.

  • Nausea and reduced appetite

    Common in acute flares alongside pain - and a marker for early review rather than pushing on at home.

  • Recurrent urinary infections

    Repeated UTIs with pneumaturia or faecaluria point to a colovesical fistula and need specialist review.

  • Painless rectal bleeding

    Diverticular haemorrhage is a common cause of lower-GI bleeding in older adults - usually painless and brisk.

  • Change in bowel habit

    A new, sustained change deserves assessment - to distinguish diverticular disease from colorectal cancer.

  • Red flag - peritonitis or shock

    Rigid abdomen, high fever, low blood pressure or collapse - a surgical emergency needing hospital care now.

Treatment

How diverticular disease is treated in the UK.

Lifestyle first, medicines and short admissions for flares, and colorectal surgery reserved for complications and quality-of-life-limiting recurrence.

  • Fibre, fluids and lifestyle

    Twenty-five to thirty grams of fibre a day, generous fluids, weight management, exercise and stopping smoking - the backbone of long-term care.

  • Reduce NSAIDs and red meat

    Cut back regular NSAIDs and heavy red-meat intake - both are linked to more flares and complications.

  • Trial mesalazine or rifaximin

    In symptomatic uncomplicated disease a specialist may consider a trial of mesalazine, rifaximin or probiotics - evidence is mixed but selective use continues.

  • Selective antibiotics

    For mild acute uncomplicated diverticulitis NICE and international bodies now support avoiding antibiotics in carefully chosen patients - reserved for systemic upset or complications.

  • Hospital care and IV antibiotics

    Co-amoxiclav or metronidazole with ciprofloxacin, IV fluids and bowel rest - for moderate or severe disease.

  • Analgesia - paracetamol first

    Paracetamol is the safer choice in an acute flare - NSAIDs and opioids are generally avoided where possible.

  • Percutaneous drainage or surgery

    CT-guided drainage for larger abscesses, Hartmann or resection with primary anastomosis, and selective laparoscopic lavage for complicated disease.

  • Elective laparoscopic sigmoid colectomy

    For recurrent or complicated disease - an individualised discussion balancing quality of life against surgical risk.

What this guide is based on

The sources behind every claim on this page.

UK national guidance and specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP, gastroenterologist or colorectal surgeon knows your history and can tell you which parts apply to you. If in doubt, get seen.

  • NICE. Diverticular disease: diagnosis and management (NG147).

  • British Society of Gastroenterology. Guidance on diverticular disease and lower-GI bleeding.

  • Association of Coloproctology of Great Britain and Ireland (ACPGBI). Position statement on diverticular disease.

  • American Gastroenterological Association. Clinical practice guideline on acute diverticulitis.

Red flags

When diverticular disease needs urgent attention.

Most flares settle at home or with a short hospital stay. These are the situations that need same-day assessment or emergency care.

  • Peritonitis

    A rigid, board-like abdomen with fever, rapid pulse or collapse - a surgical emergency needing immediate hospital assessment.

  • Sepsis or shock

    High fever, confusion, low blood pressure or a very high heart rate - dial 999 or attend A&E without delay.

  • Brisk rectal bleeding

    Large volume painless PR bleeding with dizziness, pallor or fainting - always needs urgent assessment.

  • Suspected fistula

    Recurrent UTIs, air or stool in the urine or vaginal passage of gas or stool - specialist colorectal review is needed.

  • Bowel obstruction

    Colicky pain, distension, vomiting and absent bowel movements - hospital assessment on the same day.

  • Persistent change in bowel habit

    A new, sustained change over weeks - especially with weight loss or anaemia - deserves urgent colonoscopy to exclude cancer.

  • Weight loss and anaemia

    Unintentional weight loss, iron-deficiency anaemia or night sweats are not typical of diverticular disease alone.

  • Immunosuppression

    People on steroids, chemotherapy or biologics can have severe diverticulitis with few outward signs - a lower threshold for imaging.

  • Recurrent flares

    Two or more admissions or ongoing symptoms warrant an elective colorectal review to discuss long-term options.

Living with it

A common condition, with a clear plan.

Four things that make the biggest difference day to day - a fibre-rich diet, healthy habits, sensible painkillers and knowing when to be seen.

A quiet reminder

Consistency beats intensity, every time.

Small, steady habits kept up for months do more than a heroic week that does not last.

  1. 01 Fibre

    Aim for 25 to 30 grams a day

    Wholegrains, pulses, fruit and vegetables spread across meals. Increase slowly with plenty of water to avoid bloating.

  2. 02 Habits

    Move, keep a healthy weight

    Regular walking or exercise and a healthy body weight reduce flares. Stopping smoking helps most of all.

  3. 03 Meds

    Mind your painkillers

    Cut back regular NSAIDs and be cautious with opioid painkillers. Paracetamol is usually a safer starting point.

  4. 04 Escalate

    Know when to be seen

    New fever, worsening pain, rectal bleeding or feeling unwell means being seen the same day rather than waiting it out.

Frequently asked

Everything we get asked about diverticular disease.

Quick answers on the spectrum, antibiotics, surgery and prevention.

  • What is diverticular disease?

    It is an umbrella term for a spectrum - from asymptomatic diverticulosis (small pouches in the colon) to symptomatic uncomplicated diverticular disease, acute diverticulitis and complicated disease with abscess, fistula, obstruction or bleeding. Most people with pouches never develop symptoms.

  • What causes it?

    A Western low-fibre diet, chronic constipation, obesity, smoking, high red-meat intake and regular NSAIDs are the main lifestyle drivers. Age, genetics and the gut microbiome also play a part, which is why diverticula are so much more common after 60.

  • How is diverticulitis diagnosed?

    A CT scan of the abdomen and pelvis with contrast is the gold standard - it confirms inflammation, stages severity using the Hinchey classification and picks up abscess or perforation. Bloods (FBC, CRP and U&Es) support the picture, and a colonoscopy is usually done six to eight weeks after recovery to rule out cancer.

  • Do I always need antibiotics?

    No. Modern NICE and international guidance supports avoiding antibiotics in carefully selected patients with mild acute uncomplicated diverticulitis. Antibiotics are reserved for people with systemic upset, comorbidities, immunosuppression or complications. Your clinician will decide based on your specific picture.

  • Do I need surgery?

    Most people never need surgery. It is reserved for complicated disease - perforation, larger abscesses not amenable to drainage, obstruction or fistula - and for a small group with recurrent, quality-of-life-limiting flares. Elective laparoscopic sigmoid colectomy is the usual planned operation.

  • Can I prevent flares?

    You can meaningfully reduce your risk. A fibre-rich diet (25 to 30 grams a day), plenty of fluids, a healthy weight, regular exercise, stopping smoking and cutting back on regular NSAIDs and heavy red-meat intake all lower the chance of flares and complications.

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