# Is it dangerous to breathe flatulence?

**URL:** <https://boards.straightdope.com/t/is-it-dangerous-to-breathe-flatulence/642934>\
**Category:** Factual Questions\
**Created:** [December 4, 2012, 4:39am UTC](https://boards.straightdope.com/t/is-it-dangerous-to-breathe-flatulence/642934 "2012-12-04T04:39:09Z")\
**Posts on this page:** 12\
**Page:** 1

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**Author:** ![robert\_columbia](https://avatars.discourse-cdn.com/v4/letter/r/e79b87/32.png) [@robert\_columbia](https://boards.straightdope.com/u/robert_columbia)\
**Post date:** [December 4, 2012, 4:39am UTC](https://boards.straightdope.com/t/is-it-dangerous-to-breathe-flatulence/642934/1 "2012-12-04T04:39:09Z")

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I know it’s often unpleasant, but is intestinal fart gas dangerous to health in any meaningful sense? For example, has anyone been told by a doctor that they need to spend less time in enclosed spaces where a lot of people are farting because they are breathing too much of it and it is causing health problems?

E.g.

Patient: “I have a headache all the time.”  
Doctor: \<performs examination\>  
Patient: “What is it, doctor?”  
Doctor: “It looks like you have hyperhenogeical displasia. This is often caused by inhaling excessive intestinal gas.”  
Patient: “Intestinal gas? You mean farts? Oh, I work in a small office next to three guys who eat beans for lunch every day.”  
Doctor: “That could be it. Can you open a window?”

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**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\
**Post date:** [December 4, 2012, 11:53am UTC](https://boards.straightdope.com/t/is-it-dangerous-to-breathe-flatulence/642934/2 "2012-12-04T11:53:48Z")

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I very much doubt it. Flatus, even when it’s stinky, is still mostly plain old air so I doubt the concentration of anything noxious is going to be high enough to do you any harm, barring some sort of Human Caterpillar-style delivery.

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**Author:** ![don\_t\_ask](https://avatars.discourse-cdn.com/v4/letter/d/e68b1a/32.png) [@don\_t\_ask](https://boards.straightdope.com/u/don_t_ask)\
**Post date:** [December 4, 2012, 1:09pm UTC](https://boards.straightdope.com/t/is-it-dangerous-to-breathe-flatulence/642934/3 "2012-12-04T13:09:56Z")

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It’s pretty dangerous if you are breathing it out! [Fecal breath odor](http://books.google.com.au/books?id=gU4Lfsess6cC&pg=PA151&lpg=PA151&dq=bowel+obstruction+faecal+breath&source=bl&ots=egk9dBfrcM&sig=xmix3Y-E9n-rc12RaDZySA13Bvo&hl=en&sa=X&ei=Sfa9UKWnJ6yhiAeO6IGACA&ved=0CCwQ6AEwAA#v=onepage&q=bowel%20obstruction%20faecal%20breath&f=false)

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**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\
**Post date:** [December 4, 2012, 1:20pm UTC](https://boards.straightdope.com/t/is-it-dangerous-to-breathe-flatulence/642934/4 "2012-12-04T13:20:50Z")

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[According to Wiki](http://en.wikipedia.org/wiki/Flatulence#Production.2C_Composition_.26_Odor), \>99% is plain air.

> [@](#):
>
> Flatus (intestinal gas) is mostly produced as byproduct bacterial fermentation in the gastroinestinal (GI) tract, especially the colon.[6] There are reports of aerophagia (excessive air swallowing) causing excessive intestinal gas, but this is considered rare.[7] \>99% of the volume of flatus is composed of non-odorant gases.[5] These include oxygen, nitrogen, carbon dioxide, hydrogen and methane. Nitrogen is not produced in the gut, but a component of environmental air. Patients who have excessive intestinal gas that is mostly composed of nitrogen may have aerophagia.[8] Hydrogen, carbon dioxide and methane are all produced in the gut and contribute 74% of the volume of flatus in normal subjects.[9] Methane and hydrogen are flammable, and so flatus containing adequate amounts of these can be ignited.[citation needed] However, not all humans produce flatus that contains methane. For example, in one study of the feces of nine adults, only five of the samples contained archaea capable of producing methane.[10]
> 
> The remaining trace (\<1% volume) compounds give flatus its odor. Historically, compounds such as indole, skatole, ammonia and short chain fatty acids were thought to cause the odor of flatus. More recent evidence proves that the major contribution to the odor of flatus comes from a combination of volatile sulfur compounds (VSC).[11][5] It is known that hydrogen sulfide (H2S), methyl mercaptan (MM, methanethiol, MT), dimethyl sulfide (DMS), dimethyl disulfide (DMDS) and dimethyl trisulfide (DMTS) are present in flatus. The Benzopyrrole volatiles indole & skatole actually have a mothball type odor,[12] and therefore probably do not contribute greatly to the characteristic odor of flatus.

Not exactly a dangerous concentration.

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**Author:** ![simster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/simster/32/1047_2.png) [@simster](https://boards.straightdope.com/u/simster)\
**Post date:** [December 4, 2012, 1:53pm UTC](https://boards.straightdope.com/t/is-it-dangerous-to-breathe-flatulence/642934/5 "2012-12-04T13:53:49Z")

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Only if consuming it directly from the source.

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**Author:** ![drastic\_quench](https://avatars.discourse-cdn.com/v4/letter/d/e36b37/32.png) [@drastic\_quench](https://boards.straightdope.com/u/drastic_quench)\
**Post date:** [December 4, 2012, 5:13pm UTC](https://boards.straightdope.com/t/is-it-dangerous-to-breathe-flatulence/642934/6 "2012-12-04T17:13:44Z")

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Short of a canary, I’ll find out with this gerbil.

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**Author:** ![Sicks\_Ate](https://avatars.discourse-cdn.com/v4/letter/s/258eb7/32.png) [@Sicks\_Ate](https://boards.straightdope.com/u/Sicks_Ate)\
**Post date:** [December 4, 2012, 5:17pm UTC](https://boards.straightdope.com/t/is-it-dangerous-to-breathe-flatulence/642934/7 "2012-12-04T17:17:01Z")

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> [@don\_t\_ask](#):
>
> It’s pretty dangerous if you are breathing it out! [Fecal breath odor](http://books.google.com.au/books?id=gU4Lfsess6cC&pg=PA151&lpg=PA151&dq=bowel+obstruction+faecal+breath&source=bl&ots=egk9dBfrcM&sig=xmix3Y-E9n-rc12RaDZySA13Bvo&hl=en&sa=X&ei=Sfa9UKWnJ6yhiAeO6IGACA&ved=0CCwQ6AEwAA#v=onepage&q=bowel%20obstruction%20faecal%20breath&f=false)

Fantastic name/post combination.  
I really didn’t need to know that.

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**Author:** ![Tamerlane](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tamerlane/32/7602_2.png) [@Tamerlane](https://boards.straightdope.com/u/Tamerlane)\
**Post date:** [December 4, 2012, 6:03pm UTC](https://boards.straightdope.com/t/is-it-dangerous-to-breathe-flatulence/642934/8 "2012-12-04T18:03:50Z")

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The Marquis de Sade apparently had a bit of a fetish about this. Insomuch as he made it to 74, it doesn’t seem to have done that much damage.

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**Author:** ![Jake](https://avatars.discourse-cdn.com/v4/letter/j/f475e1/32.png) [@Jake](https://boards.straightdope.com/u/Jake)\
**Post date:** [December 4, 2012, 6:09pm UTC](https://boards.straightdope.com/t/is-it-dangerous-to-breathe-flatulence/642934/9 "2012-12-04T18:09:37Z")

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> [@Sicks\_Ate](#):
>
> Fantastic name/post combination.  
> I really didn’t need to know that.

Band Name! (Fecal Breath Odor)

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**Author:** ![Thudlow\_Boink](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thudlow_boink/32/320_2.png) [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)\
**Post date:** [December 4, 2012, 6:44pm UTC](https://boards.straightdope.com/t/is-it-dangerous-to-breathe-flatulence/642934/10 "2012-12-04T18:44:21Z")

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> [@Jake](#):
>
> Band Name! (Fecal Breath Odor)

Disney-channel boy band, I assume?

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**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\
**Post date:** [December 4, 2012, 8:37pm UTC](https://boards.straightdope.com/t/is-it-dangerous-to-breathe-flatulence/642934/11 "2012-12-04T20:37:46Z")

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> [@runner pat](#):
>
> [According to Wiki](http://en.wikipedia.org/wiki/Flatulence#Production.2C_Composition_.26_Odor), \>99% is plain air.
> 
> Not exactly a dangerous concentration.

That’s not what the link says. “\>99% of the volume of flatus is composed of non-odorant gases.[5] These include oxygen, nitrogen, carbon dioxide, hydrogen and methane… Hydrogen, carbon dioxide and methane are all produced in the gut and contribute 74% of the volume of flatus in normal subjects.”

So 99% is non-stinky, but that doesn’t make it plain air (despite what I asserted above). But hydrogen, CO2 and methane are not toxic. The only risk is if the concentration is high enough to displace oxygen and cause asphyxiation. 74% of a few farts isn’t going to displace the breathable air in the room.

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**Author:** ![nion](https://avatars.discourse-cdn.com/v4/letter/n/c5a1d2/32.png) [@nion](https://boards.straightdope.com/u/nion)\
**Post date:** [December 5, 2012, 5:46am UTC](https://boards.straightdope.com/t/is-it-dangerous-to-breathe-flatulence/642934/12 "2012-12-05T05:46:48Z")

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Mythbusters did this, believe it or not. Jamie laid in a small plexiglas room with the maximum possible amount of farts per hour (they used an equivalent gas) being pumped in for a number of hours. I think the myth was about it being possible to fart yourself to death in your sleep. I really wish I was kidding. Anyways, oxygen levels never dipped to a dangerous level, so myth busted.