The Bristol Stool Form Scale (BSFS), or Bristol Stool Chart (BSC), shows the seven different categories in which human stool (feces) can be classified.

It was first developed by Dr. Stephen Lewis and Dr. Ken Heaton at the University Department of Medicine at Bristol Royal Infirmary in 1997. It still remains an easy clinical tool used by healthcare professionals and researchers to assess a patient’s stool consistency and establish his or her colon transit time. Over time, the BSFS has shown significant validity and reliability.

Using the scale, patients can keep a record of their bowel movements’ frequency and a description of their stool consistency. Stool consistency reflects the time food spends in the colon (i.e. intestinal transit time) and can therefore be indicative of a patient’s diet and the different medications they are receiving, as well as any underlying gut diseases or disorders that may be present.

It is important to bear in mind that each person’s stool consistency is different; some people have multiple movements a day, while others have one or two a week. Overall, however, stool should be soft and easy to pass.

The BSFS/BSC general guidelines are:

Types 1-2: Tendency towards constipation

Types 3-4: Normal stool

Types 5-7: Tendency towards diarrhea and urgency to use the bathroom

 Source: Lewis SJ, Heaton KW (1997). Stool form scale as a useful guide to intestinal transit time. Scand J Gastroenterol; 32(9):920-924. (Retrieved on 3/1/18)

References

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

Blake MR, Raker JM, Whelan K. (2016) Validity and reliability of the Bristol Stool Form Scale in healthy adults and patients with diarrhoea-predominant irritable bowel syndrome. Aliment Pharmacol Ther. 44(7):693-703

https://www.ncbi.nlm.nih.gov/books/NBK51939/

Continence Foundation of America (https://www.continence.org.au/pages/bristol-stool-chart.html)

Mitsuhashi S., Ballou S., Jiang ZG, Hirsch W., Nee J., Iturrino J., Cheng V., Lembo A. (published online 2017) Characterizing Normal Bowel Frequency and Consistency in a Representative Sample of Adults in the United States (NHANES). Am J Gastroenterol (published online)