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Bristol Stool Type 6: What It Actually Means

Type 6 is mushy stool with ragged edges, meaning your colon passed it along before it finished reabsorbing water. What that does and does not tell you.

Clairop Team29 min read

Photo: Cemrecan Yurtman / Unsplash

The short answer

Bristol type 6 is a mushy stool made of fluffy pieces with ragged edges. It means stool moved through the colon fast enough that the colon did not finish reabsorbing water. It is a measurement of form, not a diagnosis, and one type 6 means very little. A pattern of type 6 lasting more than four weeks, especially with more trips to the toilet, is worth investigating.

Bristol stool type 6 is a mushy stool made of fluffy pieces with ragged edges and no defined shape. Physiologically it means one thing: the stool left your colon before the colon had finished reabsorbing water from it. That is usually because it moved through faster than usual.

What type 6 does not mean is a diagnosis. It is a measurement of form, in the same way that 38.5 degrees is a measurement of temperature. A single type 6 on a Tuesday after a curry and three pints is a data point. Type 6 five times a day, every day, for four months is a different thing entirely, and the two get treated as the same thing on most pages that explain the chart.

This guide covers what type 6 physically is, what it does and does not tell you about your gut, the specific spot on the scale where even gastroenterologists disagree with each other, what a run of type 6 days should prompt, and how to describe it to a clinician in a way that leads somewhere.

What type 6 looks like, and where it sits on the scale

Type 6 is the second-loosest of the seven types. The defining feature is that it has broken apart: the pieces are fluffy and ragged rather than smooth, and the whole thing has no shape of its own. People describe it as porridge, mud, cow pat, or a cloud that disperses when it hits the water. It is still solid material. It is not liquid.

TypeDescriptionWhat it suggests
1Separate hard lumps, like nutsSlow transit, hardest to pass
2Sausage-shaped but lumpySlow transit
3Sausage-shaped with cracks on the surfaceWithin the usual range
4Smooth, soft, sausage or snake shapedThe usual target when adjusting treatment
5Soft blobs with clear-cut edgesBorderline; holds a shape but only just
6Fluffy pieces with ragged edges, mushyFaster transit, water not fully reabsorbed
7Watery, no solid piecesFastest transit

The two boundaries that matter clinically are 2 to 3 at the hard end and 5 to 6 at the loose end, because those are where "normal" becomes "abnormal" in the diagnostic criteria. Type 6 sits immediately on the abnormal side of the loose boundary, which is exactly why it is the number people end up searching for.

What type 6 actually measures: water content

Stool form is a proxy for how much water is left in the stool, and the scale tracks that reasonably well. In a validation study, 169 healthy volunteers classified their own stool sample using the scale while the researchers measured its actual water content. The two correlated (Spearman's rho 0.49), and mean water content rose in steps across the three bands: hard stools (types 1 and 2), normal stools (types 3 to 5) and loose stools (types 6 and 7) (Blake 2016).

The same study compared 169 healthy volunteers with 19 people who had diarrhoea-predominant IBS. Average stool form was 3.7 in the healthy group and 5.0 in the IBS-D group. That gap is worth sitting with for a second. Even in a group selected for loose stools, the average was type 5, not 6 or 7. A person who is at type 6 most days is well past the average for a diagnosed IBS-D population.

Why does water end up in there? The colon's job on the way out is to reclaim fluid. Give it enough time and it reclaims most of it, producing a formed type 3 or 4. Give it less time, either because the colon is contracting more vigorously or because something in the stool is holding water in place osmotically, and it reclaims less. You get type 6. Push it further and you get type 7.

Type 6 tells you about your colon, not your stomach

This is the part almost no explainer page gets right, and it changes how you should interpret the number.

The scale was validated against whole-gut transit. In the original study, 66 volunteers had transit measured with radiopaque marker pellets, kept a stool diary, and then had their transit deliberately sped up with senna and slowed with loperamide. Baseline transit time correlated with how often people went (r = 0.35) and with stool weight (r = -0.41), but best with stool form (r = -0.54). When transit was changed, the change in stool form tracked it best of all (r = -0.65) (Lewis 1997).

But a separate study pinned down which part of the gut stool form reflects. Thirty-two healthy volunteers had regional transit measured scintigraphically, with segmental colonic transit also quantified using radio-opaque markers, while recording stool form. Hard stools correlated with slow colonic transit and loose stools with fast colonic transit. Stool form could not be related to gastric emptying or small bowel transit at all (Degen 1996).

So a type 6 is a statement about your colon. It is not evidence that your stomach is emptying too fast, that food "went straight through", or that your small intestine failed to absorb anything. Those are different processes measured different ways.

There is a further honest caveat. A multicentre study of 110 adults, 46 of them chronically constipated, measured whole-gut and colonic transit with a wireless motility capsule and radio-opaque markers while participants recorded stool form. In the constipated group, form correlated moderately with transit (r around -0.6). In the healthy adults, there was no correlation between stool form and measured transit at all, in either sex (Saad 2010).

In plain terms: stool form is a decent signal when something is clearly off, and a weak one when things are broadly normal. A type 6 in someone whose bowels are otherwise fine may be telling you very little.

Is type 6 diarrhoea? The honest answer

Not on its own. Diarrhoea, as clinicians use the word, has a definition that type 6 only partly satisfies.

The British Society of Gastroenterology's chronic diarrhoea guideline works through this directly. It notes that patients think of diarrhoea in terms of consistency, and that consistency is determined by the stool's water-holding capacity, so the Bristol chart is the practical tool, with type 5 and above as the relevant band. It then explicitly abandons the old stool-weight criterion of 200 g per day as misleading, because normal stool volumes exceed that on many non-Western diets. The definition it lands on is: stool consistency between types 5 and 7 on the Bristol chart, with increased frequency, persisting for more than four weeks (Arasaradnam 2018).

Three separate elements, all needed. Consistency, frequency, duration.

That matters because one loose stool a day, even reliably at type 6, is not chronic diarrhoea by that definition. Four or five type 6 stools a day for months is. The guideline also flags a specific trap: faecal incontinence is commonly misinterpreted as diarrhoea, and the two need separating early.

This exact confusion runs through patient communities. A post in r/ibs titled simply "what do you actually class as diarrhoea" described a stool that "is trying to have some sort of formation but won't form because of rapid gut transit", breaking apart into a cloud on contact with the water, and asked whether that counted, given it was never truly liquid (r/ibs thread). The single reply made the point most people need: it does not have to be liquid, and frequency is part of the picture. That is a lay summary of exactly what the guideline says.

The place on the scale where even specialists disagree

If you have ever squinted at the chart and genuinely could not decide between 5 and 6, you are in good company, and the research is on your side.

Thirty-four gastroenterology providers across three institutions each rated 35 stool photographs using the Bristol scale, and 20 of them re-rated the same photographs later. Rated as individual types, the scale performed well: inter-rater and intra-rater reliability were excellent (intraclass correlations of 0.88 and 0.89), and 95% of ratings landed within one category of the most common rating. But when those ratings were collapsed into the clinical categories of normal versus abnormal, agreement dropped sharply. Thirteen of the 35 photographs (37%) produced significantly diverging classifications, and those 13 were precisely the ones raters split between type 2 and type 3, or between type 5 and type 6 (Chumpitazi 2016).

The validity study found the same weak spot from a different direction. When 86 volunteers classified 26 stool models, 81% of the 1,204 classifications were correct overall, which is substantial accuracy. But fewer than 80% of types 2, 3, 5 and 6 were classified correctly, and the authors concluded that difficulties arise specifically around the clinical decision points (Blake 2016).

Two practical consequences follow, and they are the most useful things on this page.

First, do not agonise over 5 versus 6. If trained specialists split on it, your uncertainty is not a personal failing. What matters more is whether your own rating is consistent over time, because that is what makes a trend readable.

Second, decide your own rule and write it down. Pick a tiebreaker and apply it every time. A workable one: if it held a recognisable shape as it came out and the pieces have clean edges, call it 5. If it came out shapeless and the edges are ragged or it broke up on contact with water, call it 6. The rule does not have to be the objectively correct one. It has to be yours and it has to be stable, so that a shift from mostly 5 to mostly 6 across a month means something real rather than reflecting a drift in how you were judging it.

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One type 6 versus a pattern of type 6

The single most common mistake is treating one bowel movement as a verdict. Stool consistency swings hard, including inside the same person on the same day.

In a study where 185 people with IBS rated the consistency of every bowel movement for 90 days, 78% had both loose or watery stools and hard or lumpy stools over the period, averaging three fluctuations between those extremes per month. Yet the pattern itself was stable: the proportion of loose stools correlated r = 0.78 between the first and second months, and hard stools correlated r = 0.85. The same study found that questionnaires overestimated how often stool consistency was abnormal compared with the diaries people actually kept (Palsson 2012).

Read that carefully, because it is doing two jobs. Individual stools vary enormously, so no single one is informative. The proportion is remarkably stable month to month, so a fortnight of logs genuinely tells you something. And your memory of how bad it has been is worse than your diary.

Loose stools also come in runs rather than scattered at random. Analysing three months of daily diaries from 124 people with IBS who were not taking laxatives, anti-diarrhoeals or IBS-specific medication, researchers found significant clustering in Bristol ratings for 69.4% of participants. Defining a diarrhoea episode as two or more loose or watery stools never separated by more than one non-loose stool or a day without a bowel movement captured 76% of all loose stools (Palsson 2014).

So a three-day stretch of type 6 is a normal shape for this to take. It is not, by itself, evidence that anything has changed.

A thread in r/ibs called the full range inside a single day a "Tour of IBS", and the replies confirmed how familiar that is, including people who get several types in one visit and one person whose swings from hard to loose and back track their menstrual cycle over 24 to 48 hours (r/ibs thread). Our guide to why IBS comes and goes goes into the episode research in more depth.

What turns one stool into a type 6

These are the everyday accelerants. Most of them are obvious in hindsight and easy to miss in the moment.

  • Coffee. In a study using ambulatory colonic manometry in 12 healthy people, caffeinated coffee produced colonic motor activity of a magnitude similar to a 1,000 kcal meal, 60% stronger than water and 23% stronger than decaffeinated coffee (Rao 1998). Decaf was not statistically different from water or from caffeinated coffee, so the caffeine is not the whole story. We cover this in detail in coffee and Crohn's disease.
  • Poorly absorbed carbohydrates in quantity. Lactose, fructose, sorbitol and other polyols draw water into the bowel and are fermented in the colon. Whether that produces symptoms depends on the dose, on how much lactase you make, on your microbiome, and on visceral sensitivity, which is itself heightened in IBS and in anxiety (Misselwitz 2019). UK guidance advises people with diarrhoea to avoid sorbitol specifically, since it turns up in sugar-free sweets, chewing gum and drinks (NICE CG61).
  • A large or very fatty meal, which drives a stronger post-meal colonic response.
  • Alcohol, often reported alongside the next morning's loose stool.
  • A gut infection, which is the most common acute cause and usually settles within days.
  • Medicines and supplements. Magnesium-containing products, some antibiotics and several common prescriptions shift stool form. This is a conversation with your prescriber, not something to change on your own.
  • A bad night's sleep or a high-stress morning. Not measurable in the toilet, but reliably reported.

If the type 6 follows an obvious trigger, resolves within a day or two, and your baseline returns, the useful response is to note it and move on. Our guide to how long after eating symptoms appear explains why the delay between a meal and a stool is longer and more variable than most people assume, which is why same-meal blame is so often wrong.

When type 6 is your everyday normal

This is the situation that brings people to this page. Not one mushy stool, but months of them.

A post in r/ibs from someone diagnosed with IBS-D described a full year without a single formed stool, "just constant fluff/mud every single day", and asked whether that was normal and whether anyone had ever got back to a formed stool (r/ibs thread). Another described a decade at type 6 with normal colonoscopies and stool tests, and the persistent fear of an underlying malabsorption problem (r/ibs thread). The worry in both is the same, and it is reasonable.

Here is what actually sits behind persistent loose stool, and how common each is.

Diarrhoea-predominant IBS. Defined by the proportion of abnormal stools that are loose rather than hard, alongside recurrent abdominal pain related to defecation or to a change in stool frequency or form (Lacy 2016). The arithmetic, including the rule that only abnormal days count towards the percentage, is worked through in the difference between IBS-D and IBS-C. Note that IBS requires pain. Persistent loose stool with no pain at all is classified differently.

Bile acid diarrhoea. The most under-recognised cause on this list. A systematic review of 18 studies covering 1,223 patients with IBS-D symptoms who then had SeHCAT scanning found moderate bile acid malabsorption in 32% (retention below 10%), mild in 26%, and severe in 10%. Response to a bile acid binder followed the severity: 96% of those with retention below 5% responded. The authors concluded that adult-onset bile acid malabsorption is not rare and that IBS guidelines needed revising to reflect it (Wedlake 2009). A later review put the figure at more than 25% of people with IBS-D or chronic diarrhoea in Western countries, and explained the testing options, including SeHCAT, serum C4 and faecal bile acid assays, and why availability varies enormously by country (Vijayvargiya 2013).

Coeliac disease. A meta-analysis of 14 studies covering 4,204 people found biopsy-proven coeliac disease in about 4% of those meeting IBS criteria, more than four times the rate in controls (Ford 2009). This is why coeliac serology appears in essentially every guideline for loose stools.

Microscopic colitis. Chronic watery diarrhoea with a normal-looking colon at colonoscopy, diagnosed only on biopsy. A meta-analysis of 42 population-based studies covering more than 75 million people estimated a global incidence of 9.36 per 100,000 person-years and a prevalence of 34.08 per 100,000, with higher rates in women, older age groups and people with certain medication exposures (Yu 2026). It is easy to miss unless biopsies are taken from the right and left colon, which is exactly what the BSG guideline recommends (Arasaradnam 2018).

Inflammatory bowel disease. Crohn's disease and ulcerative colitis usually come with additional signals, notably blood and night-time symptoms, and can be largely excluded non-invasively. In a meta-analysis, a CRP of 0.5 or below or a faecal calprotectin of 40 µg/g or below gave a 1% or lower probability of IBD in someone with IBS symptoms (Menees 2015).

Post-infectious IBS. If your loose stools started after a bout of food poisoning or gastroenteritis, that is a recognised pathway. A meta-analysis of 45 studies covering 21,421 people with infectious enteritis found IBS in 10.1% at 12 months and 14.5% beyond 12 months, with risk 4.2 times higher than in people who had not had enteritis. Protozoal or parasitic infection carried the highest risk, with 41.9% developing IBS (Klem 2017).

Carbohydrate malabsorption, principally lactose, which is dose-dependent and frequently overlaps with IBS rather than replacing it (Misselwitz 2019).

Exocrine pancreatic insufficiency, where the pancreas does not produce enough digestive enzymes. It is far less common than the causes above and tends to present with fatty, greasy, hard-to-flush stool and nutritional consequences rather than plain mushiness. Faecal elastase is the usual non-invasive screening test (Capurso 2019). One caveat visible in patient threads and in the literature: results can be harder to interpret when the sample itself is very loose, so a borderline result on a watery sample is worth discussing rather than accepting at face value.

The case nobody explains: type 6 while you are constipated

This confuses people badly, and it is common enough that it has a folk name in patient communities. Someone in the "Tour of IBS" thread described "constipated diarrhoea": stool that is soft, but which takes cramping and straining to pass (r/ibs thread).

The scale cannot represent this. It rates what comes out. It says nothing about the effort involved, whether you felt finished afterwards, or whether looser material passed around something harder that is still there. UK IBS guidance notes directly that people presenting with IBS symptoms commonly report incomplete evacuation and rectal hypersensitivity as well as urgency, and it recommends asking open questions rather than relying on a number (NICE CG61).

If this is you, the Bristol type on its own will actively mislead your clinician. Record three extra things alongside it: whether you strained, whether you felt emptied afterwards, and how long you spent. Then say those out loud in the appointment. "Mostly type 6, but I strain for ten minutes and never feel finished" points somewhere completely different from "mostly type 6, out in thirty seconds, five times a day". Our guide to what a doctor actually reads on a symptom tracker handover covers how to get that onto one page.

The same guidance flags something else worth knowing: about 20% of people experiencing faecal incontinence disclose it only if they are asked directly. Population data underline how common it is, with an age-adjusted prevalence of 12.1 per 100 among community-dwelling women in one survey of 2,800 respondents, rising with age, and with only 48% of those with severe symptoms having consulted a doctor about it (Bharucha 2005). If loose stool is coming with accidents or near-misses, that is a specific thing to raise, and it changes what your clinician will do.

What a clinician will actually do with "type 6 for three months"

Persistent loose stool has a defined pathway, and knowing it helps you ask for the right things rather than waiting for them to be offered.

TestWhat it is looking forWhere guidance places it
Full blood count and ferritinAnaemia, iron deficiencyPrimary care, first line (Arasaradnam 2018)
Coeliac serology (tTG IgA, plus a second test if IgA deficient)Coeliac diseaseRecommended in chronic diarrhoea (Smalley 2019)
Faecal calprotectin or lactoferrinInflammatory bowel diseaseSuggested as a screen, with 50 µg/g as the calprotectin threshold to optimise sensitivity (Smalley 2019)
Giardia antigen or PCRGiardia infectionRecommended in chronic diarrhoea; routine ova and parasite testing is suggested against without relevant travel history (Smalley 2019)
Bile acid diarrhoea testing (SeHCAT, serum C4 or faecal bile acids)Bile acid diarrhoeaSuggested in chronic diarrhoea (Smalley 2019); a positive diagnosis rather than an empirical trial is preferred in UK guidance (Arasaradnam 2018)
Thyroid functionOveractive thyroidIncluded in the BSG initial screen (Arasaradnam 2018)
Colonoscopy with right and left colon biopsiesMicroscopic colitis, IBD, neoplasiaRecommended where indicated; rectal biopsies alone are not sufficient for microscopic colitis (Arasaradnam 2018)

The AGA guideline is explicit that it applies to an immunocompetent adult with watery diarrhoea of at least four weeks' duration (Smalley 2019). That four-week mark is the same threshold the BSG uses, and it is the single most useful number to carry into an appointment.

Two things guidance actively steers away from are worth knowing so you do not push for them unnecessarily. NICE lists ultrasound, colonoscopy, barium enema, thyroid function, faecal ova and parasites and hydrogen breath testing as unnecessary to confirm a diagnosis in someone who already meets IBS criteria and has no alarm features (NICE CG61). The BSG guideline separately notes the aim of minimising inappropriate first-line colonoscopy in people under 40 without rectal bleeding and with a normal calprotectin (Arasaradnam 2018). Note that the two guidelines differ on thyroid testing, which is a reasonable thing to ask your clinician about rather than something to settle from a web page. If you are weighing up whether this needs a specialist at all, should I see a gastroenterologist for IBS walks through the referral decision.

Red flags: see a doctor promptly

Type 6 on its own is not an emergency. These, alongside it, are reasons to be seen promptly rather than to keep tracking.

  • Blood in the stool, or black tarry stool. Bleeding is never explained by stool form.
  • Unintentional weight loss.
  • Symptoms that wake you at night. Needing the toilet in the middle of the night is a different signal from needing it first thing in the morning.
  • Fever, or symptoms following foreign travel.
  • Anaemia, or a new iron deficiency on a blood test.
  • A persistent change in bowel habit starting over the age of 50, or a family history of bowel cancer or IBD.
  • Greasy, pale, hard-to-flush stool, particularly with weight loss.
  • Accidents or near-misses, which need naming even though they are hard to say out loud.

Alarm features such as an unexplained change in bowel habit, persistent blood in the stool and unintentional weight loss should prompt referral for further investigation (Arasaradnam 2018). None of this is a reason to panic about a mushy stool. It is a reason not to spend two years managing something alone that a blood test and a stool test could have sorted out.

A worked example: three weeks of type 6

Sam is 31, has had loose stools most mornings for about five months, and has been logging for three weeks. Here is what the log turns into.

Week 1, baseline, nothing changed. Twenty-two bowel movements. Sixteen at type 6, four at type 7, two at type 5. Between two and five a day. Urgency on 5 days. Worst window consistently between 7am and 11am. No blood. Nothing woke him at night. Two coffees most mornings, usually before eating.

Week 2. Similar, except Tuesday and Wednesday, which were both type 4 after an unusually late start and no morning coffee. He notices it and does not over-interpret it, because two days is two days.

Week 3. Back to the week 1 pattern. He also notes that a sugar-free mint habit had crept up to a packet a day, and checks the label, finding sorbitol listed.

What he writes on one page for the appointment. Loose stools most days for five months. Mostly Bristol type 6, occasionally 7, two to five times a day, worst before midday. No blood, no night-time waking, no weight loss, no fever, no recent travel. Family history: none. Medicines and supplements: one, plus a magnesium supplement started four months ago. Already tried: nothing systematic.

That last line matters. The sorbitol and the magnesium are both plausible contributors and both worth raising, but neither is something to change on a hunch mid-investigation, because doing so muddies what the tests are measuring. He mentions both and asks what to do about them.

What he asks for. Given five months of loose stools with increased frequency, he asks whether the standard chronic diarrhoea screen is appropriate: blood count and ferritin, coeliac serology, faecal calprotectin, and testing for bile acid diarrhoea if the first round is clear.

That is a two-minute handover built from twenty-one days of one-tap entries. If you want a structure for the logging itself, how to keep a food diary for IBS covers what to record and what most templates leave out, and how to explain IBS to a doctor covers the wording. This is also the kind of record Clairop is built to produce: a bowel movement logged with one tap on the Bristol scale, with urgency, blood and night-time waking underneath, and a one-page summary for the appointment. The method page explains how it handles delayed patterns and why it holds back a result until it has seen enough days to mean anything.

What actually moves stool form, honestly

This section is deliberately cautious, because the internet is full of confident claims here and the evidence is thinner than the confidence.

Soluble fibre has evidence; bran does not. A meta-analysis of 14 randomised trials involving 906 people with IBS found a significant benefit from fibre overall (relative risk 0.86, number needed to treat 10), but the benefit came only from trials of soluble fibre such as ispaghula (RR 0.83, NNT 7). Bran showed no significant effect (RR 0.90, confidence interval crossing 1) (Moayyedi 2014). UK guidance goes further, advising that fibre intake be reviewed and usually reduced, that insoluble fibre such as bran be discouraged, and that any increase should be soluble (NICE CG61). Note that these trials measured symptom improvement, not stool form specifically.

Low FODMAP changes stool form in some people, not all. In a randomised, controlled, single-blind crossover feeding trial in 30 people with IBS and 8 controls, overall gastrointestinal symptom scores were lower on the low FODMAP diet than on a typical Australian diet. People across all IBS subtypes reported greater satisfaction with stool consistency, but IBS-D was the only subtype with an actual measured change in stool frequency and stool chart scores (Halmos 2014). If loose stool is the thing you want to shift, that is the subgroup where the objective measure moved. Low FODMAP is a short, structured process with a planned reintroduction phase, best done with a dietitian, and it is not a diet to stay on. We cover how to reintroduce foods afterwards separately.

Type 4 is the recognised target when treatment is being adjusted. NICE advises titrating the dose of a laxative or antimotility agent according to stool consistency, aiming for a soft, well-formed stool corresponding to Bristol type 4 (NICE CG61). That is a prescribing decision made with a clinician, not something to work out yourself, but it is useful to know that type 4 is the number they are aiming at, because it tells you what a treatment conversation is actually trying to achieve.

Cutting the obvious osmotic loads is low-risk. Sorbitol in sugar-free products is the one guidance names explicitly for people with diarrhoea (NICE CG61), and it is worth a label check before anything more elaborate.

What none of this justifies is a long list of eliminated foods based on a few loose stools. Given how much stool form varies day to day (Palsson 2012), any change needs testing over weeks, one thing at a time, and preferably with someone qualified looking at it with you.

Myths about Bristol type 6

"Type 6 means I have diarrhoea." Only with increased frequency and, for the chronic label, more than four weeks of it (Arasaradnam 2018).

"Type 6 means food went straight through me." Stool form reflects colonic transit. It has no relationship to gastric emptying or small bowel transit (Degen 1996). Whatever you ate today is very unlikely to be what you are looking at.

"Type 6 means I'm not absorbing nutrients." Water reabsorption in the colon and nutrient absorption in the small intestine are different processes. Genuine malabsorption tends to announce itself with weight loss, greasy stool and abnormal blood tests (Capurso 2019).

"Type 6 every day means it must be IBS." IBS requires recurrent abdominal pain linked to defecation or to a change in stool form or frequency (Lacy 2016). Persistent loose stool without pain, or with alarm features, points elsewhere, and bile acid diarrhoea, coeliac disease and microscopic colitis all masquerade as IBS-D.

"If my colonoscopy was normal, type 6 is just how I am." A normal colonoscopy rules out a lot and misses microscopic colitis entirely unless biopsies were taken from the right and left colon (Arasaradnam 2018), and it does not address bile acid diarrhoea at all, which affects a substantial share of people with IBS-D symptoms (Wedlake 2009). Ask what was biopsied and whether bile acid diarrhoea was considered.

"My gut has forgotten how to make a normal stool." Stool form tracks colonic transit and water reabsorption, both of which respond to whatever is driving them. The proportion of loose stools is stable month to month, but it is a proportion, not a permanent setting (Palsson 2012).

"Everyone else is a type 4." Fewer than half of the general population have what the researchers classified as normal stool types across three consecutive movements (Heaton 1992).

How to log type 6 so the number is worth something

Four rules, and they are most of the value of the scale.

Log at the time, not at bedtime. Recall inflates. In the 90-day diary study, questionnaires overestimated the frequency of abnormal stool consistency and symptoms compared with the diaries the same people kept (Palsson 2012).

Record three fields, not one. Bristol type, whether there was urgency, and whether there was blood. Add night-time waking and straining if either applies. The type alone cannot carry the meaning.

Give it two weeks before drawing any conclusion. Long enough for the proportion to stabilise, short enough that you will actually finish. Then count: out of every bowel movement in the fortnight, what share were type 6 or 7, what share type 1 or 2, and how many a day on average. Those three numbers are your baseline, and they are what a clinician wants in the first minute.

Track a score, not a feeling, if you want to know whether something helped. The IBS Severity Scoring System scores pain severity and frequency, distension, satisfaction with bowel habit and life interference out of 500, with a 50-point change as the usual threshold for meaningful improvement (Francis 1997). A before-and-after number is a far better answer than "I think it helped a bit". How do I know if my IBS is flaring up covers building that personal baseline in more detail.

The bottom line

Bristol type 6 means your colon passed the stool along before it finished reabsorbing the water, and that is all it means on its own. It is a measurement, not a verdict, and it is measured at the one point on the scale where even specialists disagree with each other.

One type 6 is noise. A fortnight of mostly type 6, with the count of trips per day written down next to it, is a real signal. More than four weeks of loose stool with increased frequency is the point where guidance stops describing and starts investigating, and where the causes worth finding are common, testable and treatable. If you have been at type 6 for months and nobody has run coeliac serology, a faecal calprotectin and a bile acid diarrhoea test, those are the three to ask about.

And if there is blood, weight loss, night-time symptoms, fever or anaemia alongside it, that is not a tracking problem. See a doctor promptly.

Frequently asked questions

What does Bristol stool type 6 mean?
Type 6 is a mushy stool made of fluffy pieces with ragged edges, with no defined shape. It means the stool left your colon before the colon finished reabsorbing water from it, usually because it moved through faster than usual. It is a description of stool form, not a diagnosis of anything.
Is type 6 stool the same as diarrhoea?
Not on its own. The British Society of Gastroenterology defines chronic diarrhoea as stool consistency between types 5 and 7 plus increased frequency, lasting more than four weeks. One loose stool a day at type 6 does not meet that definition. Type 6 several times a day, for weeks, does.
What is the difference between Bristol type 5, 6 and 7?
Type 5 is soft blobs with clear-cut edges that still hold a shape. Type 6 is fluffy, ragged pieces with no shape, like porridge. Type 7 is entirely liquid with no solid pieces at all. The 5 and 6 boundary is genuinely hard to judge, and in one study of 34 gastroenterology providers rating stool photographs, that boundary was one of the two places raters most often disagreed.
I have had type 6 stool for months. Should I be worried?
Worried is the wrong word, but it is worth getting checked rather than living with it. Loose stool lasting more than four weeks is the trigger point in UK guidance for investigation, usually starting with blood tests, coeliac serology and a stool test for inflammation. Causes such as bile acid diarrhoea, coeliac disease and microscopic colitis are common, treatable and routinely missed.
Does type 6 stool mean I have IBS-D?
Not by itself. The IBS subtypes are defined by the proportion of your abnormal bowel movements that are loose versus hard, and IBS itself needs recurrent abdominal pain linked to your bowel habit. Loose stool with no pain at all points more towards functional diarrhoea or another cause. Only a clinician can make that call.
Can you have type 6 stool and still be constipated?
Yes, and it is a common and confusing pattern. People describe straining hard to pass something soft, or passing loose stool around a harder mass. Guidance for IBS notes that incomplete evacuation and rectal hypersensitivity are commonly reported, and neither maps cleanly onto a Bristol number. Describe the straining and the sense of incomplete emptying to your clinician, not just the type.
What causes a one-off type 6 stool?
Anything that speeds the stool through the colon or pulls water into it. Common culprits are coffee, alcohol, a large or very fatty meal, a big dose of poorly absorbed carbohydrates such as sorbitol or lactose, a gut infection, a new medication, a magnesium-containing supplement, and a stressful morning. A single type 6 after an obvious trigger usually needs nothing more than noting it.
Does type 6 mean I am not absorbing my food?
Usually not. Stool form reflects how much water the colon reabsorbed, and that is mostly about speed rather than nutrition. Genuine malabsorption tends to come with other signs, including unintentional weight loss, greasy stool that is hard to flush, and low iron or vitamin levels. If you have any of those alongside loose stool, see a doctor promptly.
How do I describe type 6 stool to my doctor?
Give the number, the count and the span: for example, mostly type 6, three to five times a day, every day for three months, worst before midday. That is more useful than adjectives. Add whether there is blood, whether anything wakes you at night, whether you are losing weight, and what medicines and supplements you take, because several of those change stool form.
Will fibre turn type 6 back into type 4?
It might help, but the evidence is narrower than the advice you usually hear. A meta-analysis of 14 trials in IBS found a benefit only for soluble fibre such as ispaghula, with no significant effect from bran. Guidance also suggests reducing insoluble fibre rather than adding it. Any change is worth trialling deliberately for a few weeks with your clinician or dietitian rather than piling several things on at once.

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