What Causes Farts That Smell Like Burning Tires?

I’ve noticed that flatulence occasionally carries the unmistakable aroma of burning tires, burnt plastic, or other burnt polymers. I’ve also had the misfortune to confirm that I’m not the only one who is capable of producing this particular odor.

What chemical compounds are responsible for this effect? Which foods might precipitate flatus that smells of burning tires??


You could check out the Michelin guide.

By “the smell of burning tires”, you probably mean sulfer dioxide (also associated with rotten eggs). Most foods contain some amount of sulfer, but I don’t know what causes it to occasionally be metabolized in that particular manner.

Foods rich in thiols and thioethers are largely to blame (though some nitrogenous compounds can add a particularly fetid odor to some farts), giving you SH2 and other more weighty mercaptans. For instance, ovalbumin (the major protein component of egg whites) is rich in cysteine (and to a lesser degree, methionine), sulfur containing amino acids, and these sulfurous functional groups are released during breakdown of these proteins in the gut. If you combine a food containing some complex carbohydrates along with one rich in these sulfur-containing compounds, you’re basically lofting relatively small amounts of these stinky chemicals with odorless CO2 and methane, produced by intestinal flora digesting the fiber. Cauliflower is one of those foods that gives you just the right combination of volume and rank odor to produce the big tire-burner farts beloved by millions.

Go to a dentist. Abscess makes the fart go “honda”.

That is absolutely brilliant.

So basically this is why you don’t eat deviled eggs and wash them down with Old Milwaukee. :eek:

And the award for most informative fart-related post goes to …

I find that a few pints of Guinness does the trick.

Calamari. It’s like eating rubberbands.

Thanks for the support, but there’s really a long history of excellent posts on the Dope about flatulence, of which mine was, at best, a brief summary.

just to complete the circle, rubber is often cured with sulfur, hence the noxious odours

Excellent point. I’m well aware of the important legacy of fart-related information on the SDMB, but thought you deserved your props none-the-less here in this thread. Maybe I should have mentioned how you were contributing to a long-standing tradition … :slight_smile: