From the schoolyard to the adult dinner table, the topic of flatulence has often been a source of both awkwardness and humor.

One question, seemingly as old as humanity itself, pertinently springs to mind – when we smell a fart, are we actually inhaling poop molecules?

Although this might not appear to be a question of paramount scientific importance, it recently became the subject of a study by Dr. Karl Kruszelnicki, an Australian doctor who grappled with this conundrum following an unusual inquiry by a rather flatulent nurse.

“She wanted to know whether she was contaminating the operating theatre she worked in by quietly farting in the sterile environment during operations, and I realised that I didn’t know,” Dr. Kruszelnicki admitted during his science phone-in radio show in Brisbane. “But I was determined to find out.”

Seeking an answer, Dr. Kruszelnicki turned to his microbiologist friend, Luke Tennent in Canberra, to devise an experiment.

What followed may have been more Monty Python than Louis Pasteur, but nonetheless, it yielded some interesting results.

A presumably close colleague of Tennent was asked to emit flatulence directly into a Petri dish from a distance of 5 centimeters.

This ‘procedure’ was conducted twice – once fully clothed, and once with the experimenter’s bare posterior exposed.

The objective was to determine whether bacteria from a nurse’s digestive system, or in layman’s terms, poop, could be transported by her flatulence and potentially contaminate patients.

The Petri dishes were left overnight for analysis. As reported in the BMJ, the dish which had been on the receiving end of the ‘unfiltered’ fart revealed the growth of two types of bacteria, typically found in the gut and on the skin.

Meanwhile, the Petri dish subjected to the ‘clothed’ fart showed no signs of bacterial growth.

“Our deduction is that the enteric zone in the second Petri dish was caused by the flatus itself, and the splatter ring around that was caused by the sheer velocity of the fart, which blew skin bacteria from the cheeks and blasted it onto the dish,” Dr. Kruszelnicki told the Canberra Times in 2001.

However, despite how this might sound, he was quick to assure that the bacteria were harmless, akin to the “friendly” bacteria found in yogurt. Based on these findings, Kruszelnicki humorously concluded, “Don’t fart naked near food.”

The research implies that if you’re in the vicinity of a fully-clothed farter, you’re likely just breathing in gas, not fecal matter. This holds true for the ‘smell’ of poop as well.

The characteristic odor of poop is actually the result of gases produced alongside the feces in the intestines, including various sulfides. A study investigating the gas composition of farts found that they are predominantly composed of odorless gases like oxygen and nitrogen.

However, other gases such as hydrogen sulfide, methanethiol, which has a rotten cabbage-like smell, and the garlic-scented dimethyl sulfide were present in small quantities in an average healthy person’s farts, as detected via rectal test tubes.

When you inhale the odiferous aftermath of flatulence, you’re not inhaling the feces themselves but the gaseous byproducts.

As unsavory as the subject may be, these findings provide some relief, or at the very least, a fun fact to break the ice at the next social gathering.

We may have moved beyond the schoolyard, but the intrigue surrounding this juvenile topic, it appears, is enduring.