Spend any amount of time online and you’ll eventually come across mention of a fart pad. Not to be confused with a fart cushion or whoopee cushion, fart pads are soft inserts made of charcoal that are intended to be slipped into one's underwear. When the wearer emits a noxious toot, the charcoal in the pad is supposed to absorb the smell and presumably keep your marriage or social function intact.

But do they work? Science actually has an answer.

A 2005 study published in The American Journal of Gastroenterology examined products that "purported to minimize problems with odoriferous rectal gas." Researchers "objectively evaluated the ability of these devices to adsorb two malodorous, sulfide gases (hydrogen sulfide and methylmercaptan) instilled at the anus."

In other words: they tested fart pads.

The method was pretty clever. Six brave volunteers had the two sulfide gases delivered into their anuses and then wore “gas impermeable Mylar pantaloons,” or special fart science pants, over their normal clothes to keep it all in place. Scientists also placed hydrogen in the anus because it can’t be adsorbed by charcoal. Examining the ratio of hydrogen to the sulfide gases would help determine how effective the charcoal pad would be in capturing the gases and their accompanying odors.

The participants' normal clothes captured roughly 5.3 percent of the gases, meaning that your average pair of underwear and pants isn’t going to do much when it comes to containing a ripper. (Since normal clothing was worn for all the various tests, the 5.3 percent was deducted from all outcomes.) Underwear made entirely of activated charcoal fabric was very effective in capturing virtually all gases, while an insert pad was able to filter between 55 percent and 77 percent.

Pads can have limited effectiveness, according to the researchers, because not all of the gas roaring out of the anus will be captured by a pad.

An earlier study in 1998 supports these findings. In that study, 16 volunteers ingested large amounts of beans and lactose, then had the intensity of their farts measured by judges who sniffed their emissions. A charcoal cushion, which is a bit heavier than a pad, absorbed more than 90 percent of sulfur gases.

The conclusion? Putting a charcoal pad in your pants will probably reduce—though not totally eliminate—the stench of your bean dinner. It also depends on how much of the pad is able to cover your rear.

If you’d like to try one out for yourself, Flat-D Innovations is offering a 7-inch by 5-inch washable fart pad for $15. You can order it on Amazon.

But be forewarned: Pads can help lessen the smell, but never the noise. There's no fart filter that's 100 percent effective in reducing shame.