You can manage chronic constipation in kids!
You can manage chronic constipation in kids!
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What the Bristol Can Tell Us

Pediatric Bristol Stool Form Scale

If your child has been to the doctor for constipation even once, you’ve likely heard of the Bristol Stool Form Scale. This is the rabbit turd to runny liquid chart that is in nearly every GI clinic. The Bristol is a handy and easy-to-use tool, but it’s important to know what the Bristol does and does not tell us about our gut. 

The Bristol Stool Form Scale (I’m going to call it the Bristol from here on out) was developed in 1997 by Ken Heaton, MD, at the University of Bristol. Doctor Heaton did much of his research on diagnosing and treating irritable bowel syndrome in adults. He published a study in 1997 that showed that stool consistency as measured by the Bristol correlated with Whole Gut Transit Time, or WGTT. WGTT is the amount of time it takes for your body to turn food into poop. “Normal” WGTT is anywhere from 19 to 70 hours, although I can only verify that on Web sites and not in any sort of scientific study. 

(Side note: I think an entire book could be written on what is “normal” when it comes to our BMs versus what is “optimal” or what actually makes us feel great. I was just reading an essay by Michael Pollan on coffee and mentioned how big a problem constipation was in 16th-century England (and how much of a relief coffee provided). What if our “norms” are just a reflection of centuries of constipation? Seventy hours sure seems like a long time for food to move through the system. But I digress...) 

The most scientific way to measure WGTT is to swallow a pill that sends wireless data to a receiver that you carry around with you for five days. You have to hit buttons on the receiver periodically during the test, and you have to log your bowel habits, what you eat and how you sleep. Then you have to dig the pill out of your stool when it ends its journey in the toilet. Another, older way to measure WGTT was to swallow a radioactive pill or radioactive food that could be tracked in your system with a gamma camera. Neither of these options is great for kids, and so we are left with the Bristol.

Dr. Heaton developed the Bristol so that medical providers could have an idea of gut transit time without having to do the invasive tests. And his research proved that a type 1 or 2 on the Bristol indicates slow colonic transit time, and a 6 or 7 indicates fast colonic transit. Because the speed of your GI tract can be a cause of constipation, it’s a useful tool. But how reliable is it with kids? 

The Journal of Pediatrics published a study in 2011 that showed that kids 8 years and older can reliably use the Bristol. Kids under 6 can not reliably rate their BMs, and kids between 6 and 8 need verbal descriptions of the ratings to be accurate. So, for younger kids, you’re going to have to check out their poops yourself. And for kids between 6- and 8-years-old, you’re going to need to have a discussion with them about the scale. 

(Here’s a link to that study:

I think a larger question here is: how useful is the Bristol? It’s important to remember that the literature only validates the Bristol as an indication of transit time. There is no research that I could find validating that certain stool types are indicative of a diagnosis of constipation. 

The medical community generally believes a type three is “normal,” but is it healthy? Optimal? There really isn’t any research to that end. Types six and seven are abnormal because they sped through the large intestine. But we would be mistaken to think that type six or seven rules out constipation. Diarrhea is a sign of constipation, because newer stool is leaking around a back-up of older, harder stool. And, in my experience, many constipated kids have type five and six stools, despite the indication from X-rays or ultrasounds that they still have a back-up of stool in the rectum. 

And the ideal poop? A type four bordering on five? Terrific! But what if a child only has one of these a day, the size of a breakfast sausage? How much poop is normal for a typical child is the subject of another blog post, but I’m fairly certain that a breakfast sausage a day is not ideal. 

I love the Bristol, and I’m thankful to Dr. Heaton for developing it and giving us a reliable way to measure colonic transit time without having to swallow radioactive pills. Just remember that it is only one tool to assess how your child is doing. You’ll learn all about the “secret signs of constipation” in my book, “The Constipation Game Plan”, which should be out in mid-November. I hope you’ll join the email list (below) so you can be one of the first to read it! I also hope you’ll pass this post along to any of your friends who might find it of interest. 



Christine Stephenson

AKA The Constipation Coach 

The Bristol Stool Form Scale is used with the generous permission of Norgine Ltd. 

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