What is the most odorous substance?

Answer 1

There is no precise answer, since "smelliest" depends on the person. Generally, the human nose can detect compounds called "Thiols" (also "Mercaptans") at parts per billion levels: one gram of methyl mercaptan can stink up an entire football stadium! (2ppb detection threshold = 2 micrograms mercaptan per cubic meter of air.)

Thiols are found in skunk spray ("low molecular weight thiol compounds"), garlic (allicin), and poop (methyl mercaptan). Industrially, thiols are added to to propane and natural gas (primarily ethyl mercaptan) specifically to make them stinky and thus easier to detect leaks.

Old answer:

I just saw this on a discovery channel show not too long ago. It was a combination of 2 or 3 things that were combined causing the worst odor known to man (at least in their opinion-I suppose it may be different for everyone) but it was like a combination of rotting meat, human feces and something else, like a skunk or something.

What I want to know is who is flipping the bill for them to find this out and why would anyone want to spend them time mixing crap and others disgusting things for a paycheck? It serves no purpose.