Farts – also called flatus (say: flay-tus) or intestinal (say: in-tes-tuh-null) gas – are made of, well, gas!

When you eat, you don’t swallow just your food. You also swallow air, which contains gases like nitrogen (say: ny-truh-jen) and oxygen (say: ahk-sih-jen). Small amounts of these gases travel through your digestive system as you digest your food. Other gases like hydrogen (say: hy-droh-jen), carbon dioxide (say: kar-bon dy-ahk-side, the gas that makes soda fizzy), and methane (say: meth-ain) are made when food is broken down in the large intestine. All of these gases in the digestive system have to escape somehow, so they come out as farts!

Gases are also what can make farts smell bad. Tiny amounts of hydrogen, carbon dioxide, and methane combine with hydrogen sulfide (say: suhl-fide) and ammonia (say: uh-mow-nyuh) in the large intestine to give gas its smell. Phew!

All people fart sometimes, whether they live in France, the Fiji islands, or Fresno, California! If you have a dog, you may have even been unlucky enough to have heard (or smelled) Fido farting. Intestinal gas is totally normal, and it’s very rare for farting to be a sign that something is wrong in the body.

For more on gas visit “Why do I fart? on Kidshealth.org”