The claim from this site:

It’s been said that the average American carries around between 5-20 extra pounds of poop in their intestines.

It's hard to believe it's true. Is there a medical evidence that proves this claim?

Losing 20 lbs (9 kg) by just flushing the intestines seems like a hoax.

  • 3
    Metric equivalents for those who don't want to bother: 5-20 pounds => roughly 2.27-9.07 kg, and according to Gallup the average american is around 175 pounds (~79kg) for reference.
    – Entropy
    Commented Sep 17, 2020 at 18:39
  • 3
    Deleted a whole lot of conjecture, pseudo-answers, inappropriate jokes and challenges to the question because commenters didn't trust the source (which is the whole point of the site: if we only quoted reliable sources, we wouldn't need to ask if they were right.)
    – Oddthinking
    Commented Sep 18, 2020 at 23:50
  • 4
    The density of wet fecal matter is 1.06 g/cc. 10kg of feces would be around 10 litres (2.6 gal) in volume - enough to fill a typical household bucket. If this claim were true, there would be no room in your torso for anything except poo...
    – avid
    Commented Sep 19, 2020 at 7:34
  • @avid counterargument: the upper bound of the volume of the small intestine, based on my quick read of Wikipedia and a back of the envelope calculation, would be around 12 lithers.
    – HAEM
    Commented Sep 19, 2020 at 11:56
  • Comments deleted...ok. Now the next question is, how did the people who sell the colon-cleansing (i.e. weight-loss) supplement come up with this figure? The ad itself is not telling a lie but inserting that "fact" insinuates that clients can lose up to 20 lbs in one sitting, which is ridiculous.
    – Mari-Lou A
    Commented Sep 20, 2020 at 9:19

2 Answers 2



According to the chapter "Carbohydrate Metabolism in the Colon" in Human Colonic Bacteria (1995) :

The large intestine contains about 220 g wet weight of contents (range circa 60–900 g), 35 g dry weight

Authors of the chapter are Philip D. Marsh, Ph.D. and Michael J. Hudson, B.Sc. Department of Pathogenicity PHLS Centre for Applied Microbiology and Research Porton Down, England.

(Converting to pounds that is 0.5 lbs. average and 2 lbs. maximum)

According to Comparison of fermentation reactions in different regions of the human colon Journal of Applied Bacteriology 1992, 72, 57-64.

Gut contents were obtained from two sudden-death victims...The wet weight of colonic contents, in subjects 1 and 2 respectively, were: caecum, 71.9 and 18.2 g; ascending colon, 86.5 and 11.9 g; transverse colon, 125.7 and 25.3 g; descending colon, 3.68 and 126.9 g and sigmoid/rectum, 56.6 and 6.1 g. Total wet weights of colonic contents were 344.4 and 188.4 g.

  • 4
    In imperial measures; lbs and ounces?
    – Mari-Lou A
    Commented Sep 17, 2020 at 19:06
  • 3
    @Mari-LouA 220 g is almost 0.5 lb, 900 g about 2 lb; 35g is about 1.2 oz
    – Henry
    Commented Sep 17, 2020 at 19:10
  • 32
    That quote only talks about the large intestine, which is much shorter than the small intestine. Is there a figure for the full intestinal tract?
    – coagmano
    Commented Sep 18, 2020 at 3:41
  • 24
    at what point in your intestine does "partially digested food" become "poop"? I guess assuming the entry to the large intestine is as good a marker as any; at that point no more nutrients will be extracted so it's all waste. Commented Sep 18, 2020 at 9:21
  • 8
    Looking more closely at this answer, not only does it not address the differences between "intestines" and "the large intestine", but it doesn't actually establish the authority of its source; for all I know reading the text of this answer, it's a link to your own blog. The answer may be correct, but it is not a good answer for this site.
    – IMSoP
    Commented Sep 18, 2020 at 11:50

Those Ads were popular on TV years ago. They all claim some permanent build-up of "extra poop" which only a cleanse can remove. I found a lovely 2018 quote from a skeptic medical office of McGill University from the head, a Chemistry instructor. The lead-up to it is quite funny and mentions earlier Ads. This part makes one embarrassed to have even considered lingering poop:

Now let’s get real here. Have pathologists who have carried out thousands of autopsies seen pounds of goo encrusted in intestines? No. Have colo-rectal surgeons who have operated on colons thousands of times seen such sludge? No. Have radiologists who have perused thousands of x-rays of the colon noted the buildup of “mucoid plaque?” No. Why? Because it doesn’t exist. The term itself was the invention of naturopath Richard Anderson who created Arise and Shine, a popular colon cleanser.

Not a proof, but he's reminding us of what we should know: the colon isn't some obscure part of the body no one has ever looked at before.

A search on Mucoid Plaque leads to a Wikipedia entry, funny but not as funny as the article above, with:

While colonic irrigation enjoyed a vogue in the early 20th century as a possible cure for numerous diseases, subsequent research showed that it was useless and potentially harmful [...] ( Ernst, E (June 1997). "Colonic irrigation and the theory of autointoxication: a triumph of ignorance over science". Journal of Clinical Gastroenterology. 24 (4): 196–198).

Then later directly addressing the "pounds of stuck poop":

Commenting on claims that waste material can adhere to the colon, Douglas Pleskow, a gastroenterologist at Beth Israel Deaconess Medical Center, stated, "that is the urban legend. In reality, most people clear their GI tract within three days." (Foreman, Judy (June 30, 2008). "Beware of colon cleansing claims". Los Angeles Times).

So there's no extra poop. Food goes in, and at most 3 days later it's all out.

  • 14
    This feels almost like a good answer, but it's rather let down by phrasing like "things everyone knows about the colon". I've personally never examined a colon, so have no personal knowledge of what it does or doesn't contain. Focussing on the actual authorities who do know these things would make for a better answer.
    – IMSoP
    Commented Sep 18, 2020 at 11:48
  • 1
    I think the final quote may not have stated it clearly. I believe that the case is not that your colon is clear, but that what you put in should be fully processed and ready for expulsion within three days. So whatever you have eaten within the last 3 days, is still somewhere along the line being processed. So when you take your Magnesium Citrate for a colonoscopy, you are rushing your last 3 days worth of ingested materials through the process so that your tract can be clear. Commented Sep 18, 2020 at 18:36
  • @MichaelRichardson But the Q is about the extra poop, right? The stuff the linked advertisement says can stay there for years. The point of the claim is that only their product can get out this permanent 20 pounds, right? Even so, I'll try to clear that up. Commented Sep 19, 2020 at 2:45
  • @IMSoP I feel like the best answers in Skeptics include some critical thinking. Most people are aware that colons are regularly examined. But "everyone knows" is probably a bad phrase here. Commented Sep 19, 2020 at 3:33
  • 3
    What did you mean by "the back of Pluto"... did you mean "the back of Uranus"?
    – Michael
    Commented Sep 19, 2020 at 5:41

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .