Health condition · Clinically reviewed
IBS, the guide that answers what to do next.
A real, common condition with modern treatments that go well beyond peppermint tea. Here is how it is diagnosed and what actually helps.
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, BSG or peer-reviewed sources you can see at the end.
- 03
Current for 2026
Reflects current UK guidance on IBS diagnosis, low-FODMAP diet, and drug-free options.
Key facts
IBS at a glance.
The essentials, in plain English — what it is, how common it is, how it is diagnosed, and how it is treated in the UK today.
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What it is
A functional bowel disorder — abdominal pain plus altered bowel habit, with no structural disease found on tests.
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How common
Around 1 in 10 UK adults; more common in women.
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Subtypes
IBS-C (constipation), IBS-D (diarrhoea), IBS-M (mixed).
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Diagnosis
Symptom-based (ROME IV criteria) after excluding red flags and coeliac disease.
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First-line
Dietary changes (regular meals, low-FODMAP trial), fibre adjustment, stress reduction.
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When to escalate
Rectal bleeding, weight loss, family history of bowel cancer, symptoms starting after 50 — urgent referral.
Why this guide matters
A real diagnosis, a real plan.
IBS is common, treatable and — importantly — a positive diagnosis. The three points below shape everything else on this page.
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Diagnosed positively, not by exclusion
The right pattern plus no red flags is a diagnosis — not a shrug.
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Diet, brain and gut all matter
Low-FODMAP, gut-directed hypnotherapy and targeted drugs work best together.
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Red flags matter
Rectal bleeding, weight loss, or new symptoms after 50 need urgent review, not reassurance.
How the diagnosis is made
From first symptoms to a clear plan.
The steps a UK GP will normally follow, in order — so you know what to expect and why.
Phase 1 · Recognising
Spotting the pattern and screening for red flags
Phase 2 · Confirming
Blood tests and faecal calprotectin to exclude other causes
Phase 3 · Managing
A stepwise plan across diet, drugs and therapy
- 01
Recognising
Pattern of symptoms
Abdominal pain that improves with defaecation, or change in bowel habit or stool form.
- 02
Recognising
A symptom & food diary
2–4 weeks of daily notes reveals patterns and triggers — foundational for diagnosis and management.
- 03
Recognising
Red-flag screening
Rectal bleeding, weight loss, nocturnal symptoms, over 50 with new symptoms — all trigger urgent referral.
- 04
Confirming
Baseline blood tests
Full blood count, inflammation markers (CRP), coeliac antibodies, thyroid function.
- 05
Confirming
Faecal calprotectin
A stool test that helps distinguish IBS from inflammatory bowel disease (Crohn’s, ulcerative colitis).
- 06
Managing
ROME IV diagnosis
Symptom criteria met, red flags absent, key tests negative — IBS is confirmed positively, not by exclusion alone.
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Managing
A stepwise plan
Diet, lifestyle, targeted medication and, when needed, gut-focused CBT or hypnotherapy.
Typical timeline: 4–8 weeks from first appointment to a settled plan.
Symptoms
What IBS actually feels like.
More than a “sensitive stomach” — a pattern of pain, bloating and altered bowel habit that ebbs and flows. Here is the shape of it.
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Abdominal pain
Cramping or dull pain, typically improved by opening bowels.
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Bloating & wind
Distension that worsens through the day — very common.
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Diarrhoea (IBS-D)
Loose, urgent stools — often first thing in the morning or after meals.
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Constipation (IBS-C)
Infrequent, hard, difficult stools — with a feeling of incomplete emptying.
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Urgency
A sudden, hard-to-defer urge to open bowels — especially with IBS-D.
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Mucus in stool
Passing clear or white mucus can occur in IBS — it is not typically a red flag.
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Fatigue & poor sleep
Frequently reported and often improves with better symptom control.
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Red flags
Rectal bleeding, unexplained weight loss, waking at night to open bowels, family history of bowel cancer, new symptoms over 50 — urgent GP.
Treatment
How IBS is treated in the UK.
A layered plan — diet first, then targeted medication and psychological therapy — matched to your subtype and what actually bothers you most.
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Regular meals & hydration
Sitting down for meals, not skipping, and adequate fluids reduce symptoms in many.
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Low-FODMAP trial
A structured 4–8 week trial with a dietitian, then careful reintroduction — well evidenced for symptom relief.
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Soluble fibre
Ispaghula, oats or linseed — especially useful in IBS-C. Increase slowly.
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Antispasmodics
Peppermint oil, mebeverine or hyoscine reduce cramping.
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Loperamide (IBS-D)
For diarrhoea, taken before events or as a scheduled dose.
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Laxatives (IBS-C)
Macrogol first, avoid stimulant laxatives long-term. Linaclotide for stubborn IBS-C.
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Low-dose antidepressants
Tricyclics (amitriptyline) at low dose help gut pain and diarrhoea; SSRIs help IBS-C.
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Gut-directed CBT / hypnotherapy
Strong evidence for reducing gut symptoms and improving quality of life.
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 or gastroenterologist knows your history and can tell you which parts apply to you. If in doubt, seek assessment — especially with any red-flag features.
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NICE. Irritable bowel syndrome in adults: diagnosis and management (CG61).
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British Society of Gastroenterology. IBS guidelines.
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Guts UK. Patient information on IBS.
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ROME Foundation. ROME IV diagnostic criteria.
Red flags
When it is not just IBS.
Most bowel symptoms are benign. These are the patterns that need urgent assessment — do not push through them.
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Rectal bleeding
Not typical of IBS — see a GP promptly, urgently if heavy or persistent.
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Unexplained weight loss
Especially over 10% of body weight — urgent GP.
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Nocturnal symptoms
Waking at night with diarrhoea or pain is not usual for IBS — deserves review.
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New symptoms after 50
Any new bowel-habit change over 50 needs prompt assessment.
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Family history of bowel cancer
Should lower the threshold for endoscopy — discuss with your GP.
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Iron-deficiency anaemia
On blood tests with any bowel symptoms — urgent investigation.
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Abdominal mass or lump
On self-examination or clinical exam — urgent assessment.
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Persistent vomiting
Not part of IBS — see a doctor.
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Sudden severe abdominal pain
Especially with fever — call 111 or attend A&E.
Living with it
A long-term condition, but a very manageable one.
Four things that make the biggest difference day to day — the small dietary basics, the FODMAP tool, the gut-brain link and knowing when to reassess.
A quiet reminder
Consistency beats intensity, every time.
Small, steady changes — kept up for months — do more than a heroic week that does not last.
- 01 Diet
Small changes first
Regular meals, adequate fluids and slower eating help many — before any strict diet is tried.
- 02 FODMAP
Low-FODMAP is a diagnostic tool
Do the elimination and reintroduction with a dietitian — not indefinitely on your own.
- 03 Stress
The gut and brain talk
Anxiety worsens IBS and vice versa. CBT and gut-directed hypnotherapy both help.
- 04 Reviews
Reassess if the pattern changes
A shift in symptoms — especially any new red flag — deserves another look.
Frequently asked
Everything we get asked about IBS.
Quick answers on diagnosis, FODMAP, probiotics, low-dose antidepressants, hypnotherapy and when to see a GP.
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What is IBS?
Irritable bowel syndrome — a functional bowel disorder with abdominal pain and altered bowel habit, in the absence of structural disease. Common, real, and treatable.
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How is IBS diagnosed?
By pattern (ROME IV criteria) after ruling out red flags and excluding coeliac disease and inflammatory bowel disease. Faecal calprotectin is often used.
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Do I need a colonoscopy?
Not for most IBS. It is offered when red flags are present, symptoms start after 50, or basic tests suggest another cause. See our colonoscopy page.
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What is the low-FODMAP diet?
A structured elimination diet of fermentable carbohydrates, followed by systematic reintroduction. It is a diagnostic and treatment tool — not intended to be permanent.
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Should I take probiotics?
The evidence is mixed. A 4-week trial of a specific product can be tried; discontinue if there is no benefit.
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Are antidepressants really for gut symptoms?
Yes — low-dose tricyclics reduce gut pain and diarrhoea; SSRIs can help IBS-C. Doses used for IBS are lower than for mood.
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What is gut-directed hypnotherapy?
A structured psychological therapy targeting gut-brain interaction. It has strong evidence in IBS and is available through some NHS pathways and privately.
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Is IBS caused by stress?
Not caused by stress — but symptoms are worsened by it. That is why psychological therapies work so well alongside dietary change.
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Does IBS turn into anything more serious?
No — IBS does not progress to bowel cancer or inflammatory bowel disease. But new symptoms should always be reviewed.
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When should I see a GP urgently?
Rectal bleeding, unexplained weight loss, new symptoms over 50, nocturnal diarrhoea, iron-deficiency anaemia, or family history of bowel cancer.
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