Calming The Gut

Understanding your condition

Could You Have IBS?

Millions of people live with gut symptoms for years without a clear answer. This page walks you through the clinical criteria doctors use to diagnose IBS — and the warning signs that need urgent attention.

A Real, Recognised Medical Condition

Irritable Bowel Syndrome (IBS) is a functional gastrointestinal disorder characterised by chronic abdominal pain, altered bowel habits, and bloating — in the absence of structural or biochemical abnormalities. It is not 'all in your head', nor is it simply stress.

IBS affects approximately 10–15% of the global population, making it one of the most prevalent chronic conditions seen in primary and secondary care. Despite its prevalence, it remains significantly underdiagnosed and undertreated.

The condition is classified into subtypes based on predominant bowel habit: IBS-C (constipation-predominant), IBS-D (diarrhoea-predominant), IBS-M (mixed), and IBS-U (unclassified). Each subtype presents differently and may respond to different interventions.

Anatomical illustration of the digestive system
Clinical diagnosis

The Rome IV Criteria — How IBS Is Diagnosed

IBS is diagnosed clinically using the Rome IV criteria, published in 2016 and internationally recognised as the gold standard. There is no blood test or scan that confirms IBS; diagnosis is based on symptom pattern, duration, and the exclusion of other conditions.

Core Criterion

Recurrent abdominal pain, on average at least 1 day per week in the last 3 months, associated with two or more of the following:

Related to defecation — Pain improves or worsens with a bowel movement
Change in stool frequency — More or fewer bowel movements than usual
Change in stool form — Stools appear harder, looser, or different in consistency

Duration: Symptoms must have been present for at least 6 months, with the active criteria met for the last 3 months.

Lacy BE et al. Bowel Disorders. Gastroenterology. 2016;150(6):1393–1407. doi:10.1053/j.gastro.2016.02.031

IBS Subtypes

IBS-C
Constipation-predominant
>25% of stools are Bristol Type 1–2; <25% are Type 6–7
IBS-D
Diarrhoea-predominant
>25% of stools are Bristol Type 6–7; <25% are Type 1–2
IBS-M
Mixed bowel habits
>25% of stools are both Type 1–2 and Type 6–7
IBS-U
Unclassified
Meets IBS criteria but stool pattern does not fit C, D, or M

The Bristol Stool Chart

The Bristol Stool Form Scale is a clinical tool used worldwide to classify stool consistency. It is central to IBS subtyping under Rome IV — your doctor will ask about your typical stool type to determine which subtype of IBS you have.

Type 1

Separate hard lumps, like nuts

Constipation
Type 2

Sausage-shaped but lumpy

Constipation
Type 3

Like a sausage with cracks on the surface

Normal
Type 4

Like a sausage or snake, smooth and soft

Normal (ideal)
Type 5

Soft blobs with clear-cut edges

Tending to diarrhoea
Type 6

Fluffy pieces with ragged edges, mushy

Diarrhoea
Type 7

Watery, no solid pieces, entirely liquid

Diarrhoea
Types 1–2: Constipation
Types 3–4: Normal
Type 5: Tending to diarrhoea
Types 6–7: Diarrhoea

Types 1–2 indicate slow transit (constipation). Types 3–4 are considered normal. Types 5–7 indicate fast transit (diarrhoea). IBS-C is associated with predominantly Types 1–2; IBS-D with Types 6–7.

Lewis SJ, Heaton KW. Stool form scale as a useful guide to intestinal transit time. Scand J Gastroenterol. 1997;32(9):920–924.

Important — please read

Red-Flag Symptoms — When to Seek Urgent Referral

IBS is a diagnosis of exclusion. Before IBS can be confirmed, serious conditions — including colorectal cancer, inflammatory bowel disease (IBD), and coeliac disease — must be ruled out. The following symptoms are red flags that require prompt medical evaluation and should not be attributed to IBS without investigation.

If you experience any of the following, please consult a doctor promptly. Do not assume these are IBS.

Rectal bleeding or blood in stool
May indicate colorectal cancer, IBD, or other serious pathology
Unintentional weight loss
Unexplained loss of ≥5% body weight warrants investigation for malignancy or malabsorption
Nocturnal symptoms waking you from sleep
True IBS symptoms do not typically wake patients from sleep; nocturnal diarrhoea or pain suggests organic disease
Onset after age 50
New-onset bowel symptoms in those over 50 require colonoscopy to exclude colorectal cancer
Family history of colorectal cancer or IBD
Elevated risk warrants earlier and more thorough investigation
Anaemia (iron deficiency)
Unexplained iron-deficiency anaemia may indicate occult gastrointestinal bleeding
Palpable abdominal or rectal mass
Requires urgent imaging and specialist referral
Fever with gastrointestinal symptoms
Suggests infection or inflammatory disease rather than functional disorder

NICE Guideline CG61 (Irritable Bowel Syndrome in Adults, updated 2017); Ford AC et al. Am J Gastroenterol. 2014.

What Causes IBS?

IBS does not have a single cause. Current research points to a complex interplay of biological, psychological, and environmental factors:

Gut-Brain Axis Dysregulation

The bidirectional communication between the central nervous system and the enteric nervous system (the 'second brain' in the gut) becomes disrupted, leading to abnormal gut motility and heightened pain sensitivity.

Visceral Hypersensitivity

People with IBS often have a lower pain threshold in the gut. Normal digestive processes — gas movement, bowel contractions — are perceived as painful when they would not be in someone without IBS.

Post-Infectious Triggers

IBS can develop following a gastrointestinal infection (post-infectious IBS). Studies show that 10–20% of people develop IBS after an acute bout of gastroenteritis.

Microbiome Imbalance

Alterations in the gut microbiome — the trillions of bacteria living in the digestive tract — have been observed in IBS patients, though the causal relationship is still being studied.

Psychological Factors

Anxiety, depression, and chronic stress do not cause IBS, but they significantly influence symptom severity through the gut-brain axis. This is a physiological relationship, not a psychological weakness.

Treatment landscape

Why Conventional Treatments Often Fall Short

Standard medical management of IBS typically includes dietary modifications, antispasmodics, laxatives or antidiarrhoeals, and low-dose antidepressants. While these approaches help some patients, they have significant limitations:

~30%
Patients achieve adequate symptom control with first-line treatments
High
Relapse rate when medications are discontinued
None
Currently approved pharmacological treatments address the gut-brain axis directly

This is why researchers and clinicians have increasingly turned to gut-directed psychological therapies — particularly hypnotherapy — as a more durable, mechanism-targeted approach to IBS management.

There Is a Better Way

Gut-directed hypnotherapy targets the root neurological mechanisms of IBS — not just the symptoms. Explore the evidence and understand how it works.

What is Hypnosis?Read the Research