Why Do We Pass Gas?
We pass gas because gas builds up in our intestines during digestion, and it needs a way out. Some of that gas comes from air we swallow, but a lot of it is made by bacteria in the gut as they break down food. Once it’s there, the normal movement of your intestines carries it along until eventually, well, you fart.
Some of It Is Just Air You Swallowed
Of course, some of it really is air. You swallow little bits of air all day without noticing, especially when you’re eating, drinking, or talking.
A lot of that air comes right back up as a burp. But some of it keeps traveling through your digestive system instead. If it makes it into your intestines, it eventually heads out the same way as the gas being made there.
So even though burping and passing gas both get rid of gas, they aren’t just two ends of the exact same process.
Why Does It Have to Come Out?
Once gas is inside your intestines, it doesn’t just stay in one spot. Your intestines are always moving things along as part of digestion. Those same movements push gas through too. Eventually it reaches the end of the digestive tract and comes out.
That’s really what passing gas is. It’s the digestive system getting rid of gas that’s been produced or ended up inside it.
And Why Does It Sometimes Smell So Bad?
Sometimes you pass gas and barely notice a smell. Other times, there’s no missing it.
Most of the gas in your intestines doesn’t have much of a smell. The odor comes largely from tiny amounts of sulfur-containing compounds mixed in with it. So depending on what’s being digested and what your gut bacteria produce, that mixture can change.
That’s also why one fart can be barely noticeable and the next can clear the room. The mix of gases is different.
That’s pretty much it. Digestion gives you gas, your intestines move it along, and eventually it comes out. It’s less a separate thing your body is doing and more a consequence of everything that’s already happening while you digest food.
This article is for informational purposes only and is not a substitute for professional medical advice.