Smelly, thunderous, lingering or silent, Australians are being asked to log their farts for science.
The CSIRO is hoping to capture flatulence data from tens of thousands of people, including frequency, stench, loudness and duration, to help researchers better understand the nation's gut health.
Dietician Megan Rebuli says some people find farts embarrassing and uncomfortable but healthy bodies are meant to let them go.
"Sometimes it makes a sound and it might catch you by surprise. Sometimes there's a smell that you might feel self-conscious about," she said.
“Passing wind is a natural occurrence and a sign that our digestive system is working as it should."
Ms Rebuli said the average person passes wind between seven and 20 times per day.
"It's really variable depending on the types of food that you eat, how much fibre you eat and how much you're moving around," she said.
"This is the big question - what is normal? We really want to get some good quality, comprehensive data to try to pin down that number."
She said flatulence happens when our bodies expel excess gas that is produced from breaking down and processing food.
“Different foods, medical conditions, or even the way we chew, or swallow can have an impact on how our body processes the excess gas, leading to different smells, frequency or even volume," she said.
Flatulence is made up of various gases but only one of them, hydrogen sulphide, causes strong smells.
It's produced by bacteria in the gut breaking down and fermenting a broad range of foods during digestion, but it could also be an indicator that something is wrong.
"If it's a sudden onset of something, a particularly strong smell, or if it's quite different, that could be a sign that there's something else going on, perhaps an infection or some kind of intolerance," Ms Rebuli said.
A CSIRO gut health study in 2021 found more than 60 per cent of Australians reported excessive flatulence, with more than 40 per cent experiencing it most days.
Ms Rebuli said a person's gut health was an important indicator of their overall health.
"People often complain about excess flatulence or feeling bloated and what we want to know is what is normal and what should people expect, and when things go different what would that look like?"
People aged 14 or older are invited to track their flatulence using the free Chart Your Fart phone app.
"When you go into the app you can click record and then there are five characteristics that will appear ... We've got stench, loudness, duration, linger and detectability on a sliding scale," Ms Rebuli said.
"The app will start to literally chart when you fart."
