What is the Chemical Makeup of Farts?

The typical chemical makeup of farts is 60% Nitrogen, 20% Hydrogen, 10% Carbon Dioxide, 5–10% Methane and 5% Oxygen. And even though its what makes your farts stink, Hydrogen Sulfide makes up only around 1% of your average fart. Nitrogen content can range from as low as 20% to as high as 90%. Hydrogen content can be as high as 50% with Carbon Dioxide, Oxygen and Methane typically ranging around 10% or less. Really it all depends on what you eat, how much air you ingest, and the bacteria in your particular gut.

What causes farts?

Farts are caused by two main factors, the air we swallow when we eat and gasses produced in our body, typically from the food we eat breaking down. The farts that come from mostly swallowed-air will be higher in nitrogen and oxygen. Farts that are caused by food we eat will contain more hydrogen–that’s where the stink comes from.

If you would like to know more about what farts are made of and why they exist, check out our article What is a Fart?