Irritable Bowel Syndrome
A disorder of gut–brain interaction
What it is
Irritable bowel syndrome is a chronic disorder of gut–brain interaction, defined by recurrent abdominal pain associated with changes in stool frequency or form. It is diagnosed by symptom criteria (Rome IV) and subtyped by the predominant stool pattern — constipation (IBS-C), diarrhoea (IBS-D), or mixed (IBS-M).
Why it matters
IBS is extremely common and can be genuinely disabling, yet it is often dismissed as 'nothing wrong' because the gut looks normal on investigation. That framing is wrong and unhelpful: IBS is a real disorder of gut–brain signalling with real, effective treatments — several of which are dietary and behavioural rather than pharmaceutical.
What BioSignal knows about treating this
What works for Irritable Bowel Syndrome
BioSignal’s clinical summary, most important first.
- Soluble fibre — psyllium (helps, particularly IBS-C); insoluble bran can worsen symptoms
- A low-FODMAP diet, ideally dietitian-supervised and time-limited with structured reintroduction
- Peppermint oil (modest evidence for abdominal pain)
- Gut–brain behavioural therapy — CBT and gut-directed hypnotherapy (genuinely good evidence)
- Antispasmodics for pain; loperamide for diarrhoea (symptom control)
- Gut–brain neuromodulators such as low-dose tricyclics (clinician-directed)
Signal Records relevant to this condition
Interventions and contributing factors — some of these records describe a cause rather than a cure. The rating shown is BioSignal’s confidence in that Signal Record, not a claim about how well it treats this condition. Open any of them for the full evidence.
- PsylliumHigh confidence
The best-evidenced intervention in the gut ecosystem: constipation, IBS, LDL, and glucose — cheap, boring, and genuinely effective.
- Peppermint OilModerate confidence
A genuine antispasmodic with modest, real evidence for IBS abdominal pain. Enteric-coated only — and avoid it if you have reflux.
- ProbioticsLimited evidence
Specific strains help specific conditions. 'Probiotics for gut health' in healthy adults is not supported — fibre has the better evidence.
New to this? Read these first
How this usually unfolds
- Recognize risk factors
- Get diagnosed
- Track key biomarkers
- Lifestyle first
- Evidence-based treatment
- Long-term monitoring
Who is at risk
- A previous episode of gastroenteritis (post-infectious IBS)
- Female sex
- Anxiety, depression, and stress
- Early-life adverse events
- Family history
How it's diagnosed
IBS is a positive clinical diagnosis based on Rome IV symptom criteria — not a diagnosis of exclusion requiring exhaustive testing. Limited investigation is used to exclude mimics: coeliac serology, and faecal calprotectin to distinguish IBS from inflammatory bowel disease. Alarm features (weight loss, bleeding, anaemia, onset over 50, family history of bowel cancer or IBD) warrant further evaluation.
Key biomarkers
Lifestyle
Explore this condition across BioSignal
Related Foundations
Related Signal Records
Frequently asked questions
Is IBS 'all in my head'?
No — and that framing has done real harm. IBS is a disorder of gut–brain signalling: the nerves connecting gut and brain are genuinely dysregulated, which is why psychological therapies work AND why the symptoms are physically real. Both things are true at once.
Should I try a low-FODMAP diet?
It has the best dietary evidence in IBS, but it is restrictive and is not meant to be permanent. It works best supervised by a dietitian, in three phases — restriction, structured reintroduction, and personalisation. Staying in the restriction phase long-term needlessly narrows the diet and may harm the microbiome.
Do probiotics fix IBS?
Some strains show modest benefit for some people, but the evidence is inconsistent and strain-specific — and the product you buy is often not the strain that was studied. Fibre, the low-FODMAP approach, and gut-directed behavioural therapy have stronger evidence.
Evidence summary
IBS has effective, evidence-based treatments: soluble fibre (psyllium) and the low-FODMAP diet have supportive randomised evidence, gut-directed behavioural therapies (CBT, hypnotherapy) are well supported, and peppermint oil has modest support. Probiotic evidence is inconsistent and strain-specific. Faecal calprotectin reliably distinguishes IBS from inflammatory bowel disease.
References & sources
- Rome IV criteria for disorders of gut–brain interaction
- ACG Clinical Guideline: Management of Irritable Bowel Syndrome
- BSG guidelines on the management of IBS
Educational information — not medical advice
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