Why does our bodies exude methane? The answer to my previous question of the gassy smell from the nose.?

Answer 1

Our bodies do not "exude" methane. Methane is evacuated from the body through the anus. It's called "flatulence," or farts if you want to be simple about it. The intestinal tract generates methane because of inedible fiber or the interaction in the intestines of other things we eat.

Some people fart silently, so they may not recognize where the smell comes from. A few people who have defective sphincter muscles where the stomach connects to the intestine sometimes pass gas through their mouths or noses.