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Why is my faeces black in colour the morning after I eat some Oreos?
Day 1 : Eat a handful of Oreos & the next morning your stool is black.
Day 3 : Eat a handful of cocoa flavored biscuits & the next morning your stool is normal.
Day 5 : Eat a handful of Chocolates & the next morning your stool is normal.

I have experienced similar thing where stool has a reddish tint after consuming excessive beet root. But it just takes a handful of Oreos to turn it black. But with any other biscuits or chocolates, my faeces is a normal yellowish.

I don't have anything other than anecdotal evidence but a lot (NOT ALL) of my friends have had similar experience. Just Googling "Black stool after eating Oreos" & I see a lot of people (not all) having similar experience.

Why is that the case? Why doesn't it happen to everybody? What ingredient in Oreos makes it happen? Why it happens with reference to metabolism of our body? It doesn't affect my body in any way, although I can't be sure. Asking this question with curiosity than caution. Looking for medical/biological/biochemical perspective.

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Hi KharoBangdo! I appreciate your enthusiasm on this site. While this question surely probes deep into the recesses of medical science, it seems as though your data are not well-formed. Perhaps you could carry out a more robust study and then report on the results for the community to respond to. –  jreut Jul 29 '13 at 7:00
@jreut sorry, i didnt understand what you are trying to suggest. Are u offended by my little not-so-funny joke at the end. Should i rephrase the question. Was my question unclear? –  KharoBangdo Jul 29 '13 at 7:04
Your question was clear, but your line of evidence is lacking in substance. After a cursory search of some relevant journals, I haven't found anything that answers your question. I find your post interesting albeit mal-formed. I only suggest that you conduct a more rigorous trial to get your data rather than rely on anecdotal evidence. That could at least give us an initial direction to go in. –  jreut Jul 29 '13 at 7:09
Ok. I'll rephrase the question –  KharoBangdo Jul 29 '13 at 7:18
Before you put any more effort into rephrasing your question, just know that's not what I'm asking you to do. I'm saying that your assertion that 'a handful of Oreos' vs. 'excessive beet root' causes similar magnitudes of color change in your excrement is not well-formed or founded in evidence. You simply need to be more specific in the amounts of either food you've eaten and describe more concretely the effects. –  jreut Jul 29 '13 at 7:26
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1 Answer

This is a perfectly reasonable question based on a self-adminstered (human) trial. Morever, the proposer bases their observations not on one subject but several reports. The impromptu survey of friends etc. is also acceptable. By the way, self-reported intakes/output records are an accepted method in nutrition research.

My 2-year-old child exhibited the symptoms described above, after consuming two Oreo biscuits in the afternoon. That evenings soiled nappy (diaper) revealed a dark but otherwise well-textured stool. When my concerned partner brought this to my attention, it immediately reminded me of the use of carmine red and related food dyes for the measurement of gastrointestinal transit times. The principle here is that the dyes are not absorbed in the gut, so the time from consumption to excretion gives a measure of bowel function. Short transit time means no constipation and is considered a sign of great bowel function.

Based on the observations reported for Oreos, my educated guess would be that Oreo products contain miniscule amounts of non-absorbed colorants - something that is generally regarded as safe. Self-reported symptoms are generally considered valid by health professionals. I am still intrigued by the Oreo colouring puzzle, as this colourant must be natural.

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Transgenics are also "generally regarded as safe", "because they contain DNA and our species has always eaten DNA". Just a comment. –  Rodrigo Mar 25 at 21:53
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