Bristol stool types 1 to 7: what each one means and when to worry

If you already know the basics, our shorter overview of the Bristol Stool Chart for IBD covers why gastroenterologists use it. This page goes a level deeper: what each type usually reflects, what commonly pushes stool toward it, and what to note so that a number on a chart turns into something your care team can use.

Where the scale comes from

The scale was published by researchers in Bristol, England, who showed that the form of stool tracks reasonably well with how long it has taken to pass through the gut — its transit time (Lewis & Heaton, 1997). Hard, separate lumps usually mean slow transit; loose or watery stool usually means fast transit. That is the whole idea, and it is why the scale is useful: it gives you and your clinician a shared number for something that is otherwise awkward to describe.

Two things the scale does not do. It does not measure colour, blood or mucus, and it does not diagnose anything. It describes shape and consistency only.

The seven types at a glance

This is a text version of the chart, so it works with a screen reader and prints cleanly. Descriptions are in words only.

Each type, and what tends to move it

Types 1 and 2: hard and lumpy

These usually reflect stool that has stayed in the colon long enough for a lot of water to be absorbed. Things people commonly notice before a run of types 1 and 2: drinking less, less movement than usual, travel, some medicines (including certain painkillers and iron supplements — worth asking your team about rather than stopping anything), and a big drop in fiber. The NHS page on constipation covers the general causes.

In IBD there is an extra wrinkle. Constipation can happen alongside active inflammation — some people with left-sided ulcerative colitis, for example, have hard stool with urgency or blood. And in Crohn's, hard stool with cramping and bloating can matter more if you have a known narrowing. So in IBD, a type 1 or 2 is worth logging with pain and bloating rather than dismissing as "just constipation".

Types 3 and 4: the usual range

These are what most charts call normal. The useful habit here is simply to log them. A month of records that only contains bad days makes it impossible to see what changed; a record with plenty of 3s and 4s lets you and your GI see exactly when the pattern shifted, and what shifted with it. Your own normal is the baseline — there is no prize for hitting a 4 every day.

Type 5: soft blobs

Type 5 sits on the border. For some people it is an ordinary day, especially after a large or fatty meal, a lot of coffee, or sugar-free sweets. For others it is the first step of a drift. A single type 5 means very little. Several in a row, or type 5 with more trips to the bathroom than usual, is worth noting. If you suspect coffee, our guide to coffee and Crohn's shows how to separate caffeine, milk and timing.

Types 6 and 7: loose and liquid

These reflect fast transit. Common reasons people report include a stomach bug or food poisoning, a trigger food, alcohol, sugar alcohols such as sorbitol, stress, antibiotics and other medicines — and, in IBD, a flare. One type 6 after a heavy meal is very different from five a day for a week.

In Crohn's and ulcerative colitis, what tends to matter is the trend: a drift from your usual 3s and 4s toward 6s and 7s over days, particularly with urgency, night waking or blood. That is often one of the first measurable changes before a flare, and it is exactly the kind of pattern a record shows and memory does not. If you are in that situation, how to track a Crohn's flare lists what else to log.

In IBS, loose stool is common and is one of the ways IBS is subtyped (diarrhea-predominant, constipation-predominant or mixed). The scale helps your clinician see which pattern you fit, which affects what they suggest.

Colour, blood and mucus: log them separately

Because the scale only describes form, a type 4 can still come with blood, and a type 7 can be completely free of it. Keep separate notes for:

• Blood — present or not, roughly how much, bright red or dark.
• Mucus — present or not.
• Colour changes — especially black, tarry stool, or very pale stool.
• Frequency — the number of movements in 24 hours, and how many were at night.
• Urgency — how hard it was to wait.

A form number plus these few notes is far more useful to a clinician than either on its own.

Reading a pattern, not a single day

Single readings bounce around for everyone. What is worth bringing to an appointment is a pattern over at least a week or two: your usual range, how often you were outside it, whether loose days cluster after particular meals or times of day, and whether things are drifting in one direction. Alternating between hard and loose stool is also worth mentioning, because it can point your team toward different questions than a steady change does.

Symptoms that need same-day care

The chart is for tracking, not for deciding whether something is an emergency. Contact your IBD team, an urgent care service or the emergency department the same day if you have black or tarry stool, a large amount of blood or clots, persistent type 7 with dizziness, very little urine or other signs of dehydration, a fever, severe or worsening abdominal pain, or a swollen abdomen with vomiting and no stool or gas passing. If you do not have an IBD diagnosis, new blood in your stool or a lasting change in your bowel habit is something to see a doctor about rather than track at home.

What to ask your team

• What is a normal range for me, given my diagnosis and any surgery I have had?
• How many loose stools a day, or nights waking, should prompt me to call you before my next appointment?
• Is hard stool something to worry about for me, for example if I have a narrowing?
• Should I be logging every bowel movement, or a daily typical type?
• Would a stool test, such as calprotectin, help make sense of a change I am seeing?

This guide is educational and not a substitute for advice from your own care team.