2008-04-04T07:55:00.001-07:00

Where does fart gas come from?

The gas in our intestines comes from several sources: air we swallow, gas seeping into our intestines from our blood, gas produced by chemical reactions in our guts, and gas produced by bacteria living in our guts.

What is fart gas made of?

The composition of fart gas is highly variable.
Most of the air we swallow, especially the oxygen component, is absorbed by the body before the gas gets into the intestines. By the time the air reaches the large intestine, most of what is left is nitrogen. Chemical reactions between stomach acid and intestinal fluids may produce carbon dioxide, which is also a component of air and a product of bacterial action. Bacteria also produce hydrogen and methane.
But the relative proportions of these gases that emerge from our anal opening depend on several factors: what we ate, how much air we swallowed, what kinds of bacteria we have in our intestines, and how long we hold in the fart.
The longer a fart is held in, the larger the proportion of inert nitrogen it contains, because the other gases tend to be absorbed into the bloodstream through the walls of the intestine.
A nervous person who swallows a lot of air and who moves stuff through his digestive system rapidly may have a lot of oxygen in his farts, because his body didn't have time to absorb the oxygen.
According to Dr. James L. A. Roth, the author of Gastrointestinal Gas (Ch. 17 in Gastroenterology, v. 4, 1976) most people (2/3 of adults) pass farts that contain no methane. If both parents are methane producers, their children have a 95% chance of being producers as well. The reason for this is apparently unknown. Some researchers suspect a genetic influence, whereas others think the ability is due to environmental factors. However, all methane in any farts comes from bacterial action and not from human cells.

What makes farts stink?

The odor of farts comes from small amounts of hydrogen sulfide gas and mercaptans in the mixture. These compounds contain sulfur. Nitrogen-rich compounds such as skatole and indole also add to the stench of farts. The more sulfur-rich your diet, the more sulfides and mercaptans will be produced by the bacteria in your guts, and the more your farts will stink. Foods such as cauliflower, eggs and meat are notorious for producing smelly farts, whereas beans produce large amounts of not particularly stinky farts.

Why do farts make noise?

The sounds are produced by vibrations of the anal opening. Sounds depend on the velocity of expulsion of the gas and the tightness of the sphincter muscles of the anus. Contrary to a popular misconception, fart noise is not generated by the flapping of the butt cheeks. You can see proof of this in the close-up video footage of Carl Plant's fart on Mate-in-a-State .

Why are stinky farts generally warmer and quieter than regular farts?

(Question submitted by many, many people!)

Most fart gas comes from swallowed air and consists largely of nitrogen and carbon dioxide, the oxygen having been absorbed by the time it reaches the anal opening. These gases are odorless, although they often pick up other (and more odiferous) components on the way through the bowel. They emerge from the anus in fairly large bubbles at body temperature. A person can often achieve a good sound with these voluminous farts, but they are commonly (but not always!) mundane with respect to odor, and don't feel particularly warm.
Another major source of fart gas is bacterial action. Bacterial fermentation and digestion processes produce heat as a byproduct as well as various pungent gases. The resulting bubbles of gas tend to be small, hot, and concentrated with stinky bacterial metabolic products. These emerge as the notorious, warm, SBD (Silent-But-Deadly), often in amounts too small to produce a good sound, but excelling in stench.

How much gas does a normal person pass per day?

On average, a person produces about half a liter of fart gas per day, distributed over an average of about fourteen daily farts.
Whereas it may be difficult for you to determine your daily flatus volume, you can certainly keep track of your daily numerical fart count. You might try this as a science fair project: Keep a journal of everything you eat and a count of your farts. You might make a note of the potency of their odor as well. See if you can discover a relationship between what you eat, how much you fart, and how much they smell.

How does a fart travel to the anus?

(Question submitted by Sigfrido H.)

One may wonder why fart gas travels downward toward the anus when gas has a lower density than liquids and solids, and should therefore travel upwards.
The intestine squeezes its contents toward the anus in a series of contractions, a process called peristalsis. The process is stimulated by eating, which is why we often need to poop and fart right after a meal. Peristalsis creates a zone of high pressure, forcing all intestinal contents, gas included, to move towards a region of lower pressure, which is toward the anus. Gas is more mobile than other components, and small bubbles coalesce to from larger bubbles en route to the exit. When peristalsis is not active, gas bubbles may begin to percolate upwards again, but they won't get very far due to the complicated and convoluted shape of the intestine. Furthermore, the anus is neither up nor down when a person is lying down.

Why do farts come out of your butt?

(Question submitted by the Perry family)

The butt is the location of the anus in humans, and by definition, a fart is an anal escape of intestinal gas. We should be grateful that we are not crinoids. The crinoid is a marine creature with a U-shaped gut, and its anus is located next to its mouth.

How long does it take fart gas to travel to someone else's nose?

(Question submitted by SteF)

Fart travel time depends on atmospheric conditions such as humidity, temperature and wind speed and direction, the molecular weight of the fart particles, and the distance between the fart transmitter and the fart receiver. Farts also disperse (spread out) as they leave the source, and their potency diminishes with dilution. Generally, if the fart is not detected within a few seconds, it will be too dilute for perception and will be lost into the atmosphere forever.
Exceptional conditions exist when the fart is released into a small enclosed area such as an elevator, a small room, or a car. These conditions limit the amount of dilution possible, and the fart may remain in a smellable concentration for a long period of time, until it condenses on the walls.

Why is there a 13 to 20 second delay between farting and the time it starts to smell?

(Question submitted by B_read)

Actually, the fart stinks immediately upon emergence, but it takes several seconds for the odor to travel to the farter's nostrils. If farts could travel at the speed of sound, we would smell them almost instantly, at the same time we hear them.

Is it true that some people never fart?

No, not if they're alive. People even fart shortly after death.

Do even movie stars fart?

(Question submitted by Mermaid2006)

Yes, of course. So do grandmothers, priests, kings, presidents, opera singers, beauty queens, and nuns. Even Yoda farts. See the Britney Smears music video "Oops, I farted again."

Do men fart more than women?

(Submitted by Bigdude)

No, women fart just as much as men. It's just that most men take more pride in it than most women. There is a large variation among individuals in the amount of fart gas produced per day, but the variation does not correlate with gender.
I have read that men fart more often than women. If this is true, then women must be saving it up and expelling more gas per fart than men do.

Do men's farts smell worse than women's farts?

Based on what I have experienced of women's farts, all I can say is that I hope not. Scientific studies of farts show that women's farts have a higher concentration of odor-causing gases than men's farts, but men's farts have a larger volume. The two factors equalize out (the same number of stench molecules for both), so the odor is about the same.

At what time of day is a gentleman most likely to fart?

(Submitted by David)

A gentleman is mostly likely to fart first thing in the morning, while in the bathroom. This is known as "morning thunder," and if the gentleman gets good resonance, it can be heard throughout the household.

Why are beans so notorious for making people fart?

Beans contain sugars that we humans cannot digest. The most offensive sugars, known as "flatulence factors" to scientists who research farts, are raffinose, stachiose, and verbascose. When these sugars reach our intestines, the bacteria go wild, have a big feast, and make lots of gas!
Other notorious fart-producing foods include corn, bell peppers, cauliflower, cabbage, milk, bread, eggs, beer, and raisins. People unable to digest milk due to lactose intolerance will suffer extreme flatulence if they consume dairy products.
A friend of mine had a dog who was exceptionally fond of apples and turnips. The dog would eat these things and then get prodigious gas. A dog's digestive system is not equipped to handle such vegetable matter, so the dog's bacteria worked overtime to produce remarkable flatulence.

What things other than diet can make a person fart more than usual?

People who swallow a lot of air fart more than people who don't. This can be cured somewhat by chewing with your mouth closed, eating more slowly, and not gulping food or liquids. Chewing gum, smoking, and sucking on candy also can cause a person to swallow more air. Carbonated drinks give a person extra gas. Nervous people with fast moving bowels will fart more because less air is absorbed out of the intestines. Some disease conditions can cause excess flatulence. Going up in an airplane or other low-pressure environment can cause the gas inside you to expand and emerge as flatus. Tilting your head back and pouring a drink straight down your gullet (chugging) also leads to an excess of swallowed air, and hence, farting.

Is a fart really just a burp that comes out the wrong end?

No, a burp emerges from the stomach and has a different chemical composition from a fart. Farts have less atmospheric gas content and more bacterial gas content than burps.

Is it harmful to hold in farts?

There are differences in opinion on this one. Certainly, people have believed for centuries that retaining flatus is bad for the health. Emperor Claudius even passed a law legalizing farting at banquets out of concern for people's health. There was a widespread belief that a person could be poisoned or catch a disease by retaining farts.
Doctors I have spoken to recently have told me that there is no particular harm in holding in farts. Farts will not poison you; they are a natural component of your intestinal contents. The worst thing that can happen is that you may get a stomach ache from the gas pressure. But one doctor suggested that pathological distention of the bowel could result if a person holds in farts too much. And Dr. P. said that the effort involved in retaining flatus can cause hemorrhoids.

How long would it be possible to not fart?

(Question submitted by Ineed69too)

As I understand it, a captive fart can escape as soon as the person relaxes. This means that a lot of people who assiduously refrain from farting during the day do so at great length as soon as they fall asleep. Having been on a great many overnight field trips, long bus trips, and trans-Pacific flights, I can personally vouch for the fact that lots of people do fart voluminously as they doze off. So the answer to the question would be, you can refrain from farting as long as you can stay awake!

Do all people fart in their sleep?

(Question submitted by MrBlack)

I have not made a scientific study of this, but I don't think all people fart in their sleep. I think mainly those who refuse to fart when they're awake do so when dozing off. For other people, toilet training takes such a strong hold that they let nothing pass their sphincters in sleep. For these people, the gas accumulates in the night and they vent it upon awakening.

Where do farts go when you hold them in?

How often have you held in a fart, intending to release it at the first appropriate opportunity, only to find that the fart has disappeared when you are ready for it?
I asked several doctors where the fart goes. Does it leak out slowly without the person knowing it? Is it absorbed into the bloodstream? What happens to it?
The doctors agree that the fart is neither released nor absorbed. It simply migrates back upward into the intestine and comes out later.
It is reassuring to know that such farts aren't really lost, just delayed.

How can one cover up a fart?

(Question submitted by Mouseweed)

There is a company called Fartypants that sells underwear designed to absorb the odor of farts. If you should be caught without your Fartypants, another ploy is to blame the dog or cat, if one should be present, or complain about how the wind must be blowing from the direction of the paper mill.
As for the sound... if you are in a large group of people, act oblivious and innocent, or glance quickly at the person next to you, as if you think he/she did it. Other strategies include coughing or suddenly moving your chair so that people think that they misheard the fart. If you are with one other person, you can act as if nothing happened, and the other person may believe he was mistaken in thinking he heard a fart.
CJT addresses the problem of farting loudly in a public restroom as follows: "My solution: use a handful of loose toilet paper, cover your butt hole and it will muffle the farting; my friends and I call it the 'Buff Muff'!"
Depending upon the company, another strategy is not to cover it up, but to proudly proclaim the fart as your own grand accomplishment and to issue a challenge to the others to outdo that one if they think they can.

Is it really possible to ignite farts?

The answer to that is yes! However, you should be aware that people get injured igniting flatus. Not only can the flame back up into your colon, but your clothing or other surroundings may catch on fire. A survey done by Fartcloud (the site, alas! is no more) indicates that about a quarter of the people who ignited their farts got burned doing it. Ignition of flatus is a hazardous practice. However, if you want to try it, and you don't have a friend to light your fart for you, you might find it easier to accomplish the job using the Fartlighter.
There have also been cases in which intestinal gases with a higher than normal oxygen content have exploded during surgery when electric cautery was used by the surgeon.

Why is possible to burn farts?

Farts burn because they contain methane (sometimes) and hydrogen, both of which are flammable gases. (Hydrogen was the same gas that was used in the ill fated Hindenburg dirigible.)
Farts burn with a blue or yellow flame. According to Dr. James L. A. Roth, a blue flame is indicative of the presence of methane in the flatus. Since methane producers are an elite group (only 1/3 of the population), an exclusive club called the Royal Order of the Blue Flame has been established that is open only to them. Mate-in-a-State has video footage of flatus ignition. Observe the color of the flames. These people are not methane emitters.

Is it possible to light a match with a fart?

(Question submitted by Brocolli)

No, even strike-anywhere matches have their limits, unless the fart has the consistency of sandpaper! Any fart that rough I would hesitate to call a fart. Also, farts have the same temperature as the body from which they emerge, and aren't hot enough to initiate combustion.

Are there any books about farting?

There are several! My favorite is the new book, Who Cut the Cheese: A Cultural History of the Fart by Jim Dawson. This book provides an entertaining and thought-provoking history of the fart in literature, language and society. It is very informative and very funny!
Ben Franklin's classic Fart Proudly is still in print.
There is a collection of suggestive photographs called Who Farted Now? by St. Martin's Press. Most of the photos come from old movies and political shots.
For children, we have the famous The Gas We Pass : The Story of Farts by Shinta Cho, and Amanda Mayer Stinchecum (Translator), and the Canadian picture book, Good Families Don't, by Alan Daniel and Robert N. Munsch, about a highly visible fart infesting a proper middle class family.

FART FACTS