What Bristol stool type is IBS-D?

IBS-D (diarrhoea-predominant IBS) is defined under Rome IV criteria as more than 25% of bowel movements being Bristol types 6 or 7, with fewer than 25% being types 1 or 2. Types 6 (mushy, ragged) and 7 (watery, liquid) indicate fast colonic transit and represent diarrhoea on the Bristol scale.

What Bristol stool type is IBS-C?

IBS-C (constipation-predominant IBS) is defined as more than 25% of bowel movements being Bristol types 1 or 2, with fewer than 25% being types 6 or 7. Types 1 (separate hard lumps) and 2 (lumpy sausage) indicate slow transit and constipation.

This is an educational resource, not a diagnostic tool. For persistent changes in bowel habit, any blood in your stool, unintentional weight loss, or new symptoms that worry you, book an appointment with your GP. In an emergency call 999. This site is not affiliated with the NHS, Bristol Royal Infirmary, Cleveland Clinic, or any medical institution.

Bristol Stool Chart for IBS: Understanding IBS-C, IBS-D, and IBS-M

Rome IV IBS subtypes mapped to Bristol types - Updated April 2026

What Is IBS? The Rome IV Definition

Irritable Bowel Syndrome (IBS) is a functional bowel disorder characterised by recurrent abdominal pain associated with defecation or a change in bowel frequency or form. Under the Rome IV diagnostic criteria (2016), IBS is diagnosed when recurrent abdominal pain occurs at least one day per week in the last three months, with two or more of the following: pain related to defecation; change in frequency of stool; change in form (appearance) of stool. Symptoms must have been present for at least six months.

IBS is diagnosed clinically, without specific abnormalities on investigation (no blood, no structural lesion on colonoscopy). It is one of the most common conditions managed in UK primary care, affecting approximately 10-15% of the UK population. The Bristol Stool Chart is embedded directly in the Rome IV subtyping system.

IBS Subtypes: How Bristol Types Map to Rome IV

IBS-CConstipation-predominantBristol Types 1-2

Rome IV criteria: More than 25% of stools are Bristol types 1 or 2; fewer than 25% are types 6 or 7.

Treatment focus: Psyllium, osmotic laxatives, linaclotide (NICE-approved), prucalopride

IBS-DDiarrhoea-predominantBristol Types 6-7

Rome IV criteria: More than 25% of stools are Bristol types 6 or 7; fewer than 25% are types 1 or 2.

Treatment focus: Loperamide, antispasmodics, low-FODMAP diet, colestyramine if BAD suspected

IBS-MMixedBristol Types 1-2 and 6-7

Rome IV criteria: More than 25% of stools are types 1 or 2 AND more than 25% are types 6 or 7 (both criteria met).

Treatment focus: Symptom-led: manage whichever pattern predominates at the time

IBS-UUnclassifiedBristol Inconsistent

Rome IV criteria: Meets IBS criteria but stool pattern does not fit C, D, or M.

Treatment focus: Symptom-led management

How to identify your subtype: Log your stool type daily for at least two weeks using our private tracker. Count what percentage of entries are types 1-2 and what percentage are types 6-7. Apply the 25% thresholds above. Share this data with your GP.

NHS IBS Treatment Pathway

1. Diet: Low-FODMAP

The low-FODMAP diet is the most evidence-based dietary intervention for IBS. FODMAPs (Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols) are short-chain carbohydrates that are poorly absorbed in the small intestine and rapidly fermented by gut bacteria, producing gas and triggering IBS symptoms. The diet involves a 3-6 week elimination phase followed by a structured reintroduction to identify individual triggers.

NICE recommends undertaking low-FODMAP under dietitian supervision where possible. The Monash University Low FODMAP App (developed by the team that created the diet) is available for iOS and Android and provides a comprehensive food guide. Up to 75% of IBS patients report symptom improvement on low-FODMAP.

2. Fibre

For IBS-C, soluble fibre (psyllium husk, oats) generally helps. Insoluble fibre (wheat bran) can worsen bloating and pain in IBS-D. For IBS-D, a low-fibre diet during flares is sometimes helpful, with gradual reintroduction.

3. Probiotics

NICE IBS guidance recommends a trial of probiotics for at least four weeks. The most studied strains for IBS specifically are: Bifidobacterium infantis 35624 (Alflorex) - has UK clinical trial data and is the most-cited strain in NICE IBS guidance; Symprove (multi-strain liquid probiotic) - has UK RCT data for IBS symptom reduction; Lactobacillus plantarum 299v (Digestive Advantage IBS, ProVen). See probioticvsprebiotic.com for the full evidence comparison.

4. Antispasmodics

For abdominal cramping and spasm: mebeverine (Colofac), hyoscine butylbromide (Buscopan), and peppermint oil capsules (Colpermin, Mintec) are all available in the UK. Peppermint oil has the most evidence for overall IBS symptom reduction and is effective for both IBS-C and IBS-D variants.

5. Subtype-Specific Prescription Options

IBS-C

Linaclotide (Constella) - NICE-approved, prescribers only
Prucalopride (Resolor) - for chronic constipation not responding to laxatives

IBS-D

Loperamide (Imodium) - OTC, reduces frequency
Colestyramine - if bile acid diarrhoea suspected
Eluxadoline - specialist-only for IBS-D

6. Psychological Therapies

Cognitive Behavioural Therapy (CBT) and gut-directed hypnotherapy both have strong evidence for IBS and are recommended by NICE. CBT for IBS is available on the NHS in many areas, either face-to-face or digitally. Gut-directed hypnotherapy has a 70% response rate in clinical trials and is effective for all IBS subtypes. Access varies by region; ask your GP for a referral or seek an accredited practitioner privately.

Type 1 (IBS-C)Type 2 (IBS-C)Type 6 (IBS-D)Type 7 (IBS-D)Bowel Tracker IBD (not IBS)

Updated April 2026. Sources: Rome IV criteria (2016). NICE CG61 IBS guidance. NICE NG167 (linaclotide). Monash University FODMAP research. Alflorex IBS trial data.