Why Do Farts Smell?

Everyone passes wind - we expel oxygen, nitrogen, carbon dioxide, hydrogen, and methane from our behinds every day, often without noise or smell.

However, sometimes undigested food passes from the small intestine into the large intestine (or colon) where the mass is fermented by the large amounts of bacteria normally present there. The colon contains a variety of digestive enzymes that feed off unabsorbed nutrients, foreign enzymes know as "gas enzymes" consume undigested nutrients by breaking their chemical bonds. This produces a gas that is responsible for making farts smelly. The more sulphur rich the foods you eat are the more your farts will smell as it is hydrogen sulphide which is the smelly culprit.

Farting isn't always caused by eating too many beans, being inactive can also make you more windy. Exercise helps regulate the digestive process so sufferers can relieve their symptoms by simply going for a walk.

The gases come from the fermentation of undigested food (bean skins, for example) and sometimes from swallowed gas (air, beer, carbonated beverages).
Although the majority of the gas is methane, carbon dioxide, or byproducts of the rotting process, the bad smell comes from hydrogen sulfide and mercaptan (sulfur dioxide). These are generated by bacteria as they further act on the materials in the large intestine. Complex nitrogen compounds can also alter the composition and smell.

Because its air (gas) produced inside the body and its cause by internal fermentation of sometimes bad foods or foods high in sulfuric compounds such as broccoli,asparagus,cabbage and other foods

Because when organic substances biodegrade, the byproduct is sulphur, like a strike anywhere match. Be warned tho...700 ppm will kill you in one breath...That is 0.007% No pun intended!