Bristol Stool Chart
The seven types, what each one indicates about how fast things are moving, and what tends to shift it. Tap the one that matches.
Tap the type that looks closest to what you're seeing.
What tends to shift it
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Stool form isn't the whole picture. Contact your provider if you have:
- Blood in your stool, or black/tarry stool
- Unexplained weight loss beyond what the medication accounts for
- Diarrhea that wakes you at night
- Fever, or severe or persistent abdominal pain
- A sudden lasting change in your usual pattern, particularly if you're over 50 and haven't had age-appropriate colon screening
- A family history of colorectal cancer or inflammatory bowel disease alongside new symptoms
Why this scale exists.
Stool form is a rough proxy for how long something spent in the colon — the longer the transit, the more water gets reabsorbed and the harder and more fragmented the result. The Bristol Stool Form Scale was developed at Bristol Royal Infirmary by Lewis and Heaton and published in 1997, and it gave clinicians and patients a shared vocabulary for something people find genuinely difficult to describe.
Types 1–2 point to slower transit; types 3–4 are the target range; types 5–7 point to faster transit.
GLP-1 medications slow gastric emptying and transit by design, which is why types 1 and 2 are the common report.
A single day tells you very little. A week of entries tells you something. Tracking the trend is the point. See the three levers.
Common Questions
Which type is normal?
Types 3 and 4 are generally treated as the target — formed, smooth, passed without straining. That said, "normal" varies between people, and a change from your own usual pattern is more informative than any single type.
What type is common on a GLP-1?
Types 1 and 2. These medications slow transit deliberately, and slower transit means more water pulled back out of the stool. See why GLP-1 medications cause constipation.
Can I move from type 1 to type 4?
That's the whole aim of a regularity routine — adding form with fiber, adding water with magnesium, and supporting movement itself. Start with the fiber ramp calculator.
Is this a diagnosis?
No. It's a description. It's genuinely useful for tracking change and for telling a clinician what you're actually seeing, which is otherwise a hard conversation to have precisely.
Sources
- Lewis SJ, Heaton KW. Stool form scale as a useful guide to intestinal transit time. Scand J Gastroenterol 1997. PMID 9299672.
- Gastrointestinal adverse effects of GLP-1 receptor agonists and their management. Gorgojo-Martínez et al., J Clin Med 2022. PMID 36614945.
- Adverse effects of over-the-counter laxatives. Rao & Brenner, J Am Assoc Nurse Pract 2022. PMID 35943487.
Staying regular on a GLP-1: my simple daily routine.
Get my free guide — the three levers that work, and the mistakes I see people make.