To put it one way, small doses of hydrogen sulfide help keep cells healthy and thus help ward off maladies such as dementia, diabetes, and even cancer, FoxNews reported.

To put it another way, researchers discovered that while hydrogen sulfide—the stuff produced in the gut that causes gas—is toxic in large doses, it's actually quite beneficial in smaller ones.

Specifically, it preserves mitochondria, which are vital to cell life.

They're not asking people to sniff appropriately. Rather, they've developed a compound called AP39 designed to deliver just the right dose of the stuff to cells.

Studies on actual humans come next, but in the meantime, it might pay to thank that guy in the elevator for saving your life.

Or not.