What makes farts stink?

The odor of farts comes from small amounts of hydrogen sulfide gas and skatole in the mixture. These compounds contain sulfur. The more sulfur-rich your diet, the more sulfides and skatole will be produced by the bacteria in your guts, and the more your farts will stink. Foods such as cauliflower, eggs and meat are notorious for producing smelly farts, whereas beans produce large amounts of not particularly stinky farts.