A coin-sized device attached to underwear measures how often someone farts
Brantley Hall University of Maryland
Many people underestimate their flatulence frequency, but innovative smart underwear can offer a more precise measurement, potentially identifying undiagnosed gut issues like lactose intolerance.
Brantley Hall from the University of Maryland, along with his team, has developed a compact hydrogen-detecting gadget. This device, which attaches to underwear, tracks fart frequency. “The device is about the size of a medium coin, similar to a nickel or two-pence piece, and a few coins thick. It clips on next to the perineum,” explains Hall.
Hall and his team engaged 37 participants to use the device and monitor the effects of consuming lactose, a sugar found in dairy. Excessive intestinal gas is a common sign of lactose intolerance because those lacking the lactase enzyme cannot digest lactose, leading microbes to ferment it instead. This process produces hydrogen, causing bloating and gas release. Notably, around one-third of lactose-intolerant individuals don’t report symptoms, sometimes because they are unaware of their own flatulence.
To establish a baseline, researchers put the participants on a low-fiber diet for two days to reduce microbiome activity. On the third day, each participant received either 20 grams of lactose or sucrose. On the fourth day, they consumed the opposite sugar. Neither the participants nor the research team knew who received which sugar when.
Among the 37 participants, 24 showed sensitivity to lactose, surpassing their baseline fart frequency by over 1.5 times the day after lactose consumption, as recorded by the smart underwear. For 22 of these individuals, the day with higher gas production coincided with lactose intake.
However, a related survey found that participants could only identify the day they were gassier half of the time, akin to a coin flip, according to Hall. “People aren’t reliable narrators about their flatulence patterns.”
The findings will be presented by Hall at the Digestive Disease Week 2026 conference in Chicago on May 4. He believes the device can objectively quantify gas production, aiding in the diagnosis of conditions like irritable bowel syndrome. It may also help in evaluating the effectiveness of treatments aimed at reducing intestinal gas.
Tom van Gils from the University of Gothenburg in Sweden commented on the device, noting that measuring flatulence directly at the point of emission with non-invasive smart underwear is intriguing, especially given its acceptance. He has researched how subjective flatulence sensations are relevant symptoms but suggests that objective measurements could enhance understanding of the physiological changes in certain gastrointestinal disorders.
Recent research by Hall and his colleagues indicates that healthy adults fart between four and 59 times daily, with an average of 32. “That figure is likely to go down over time because our studies are probably biased towards people who are farting a lot,” Hall notes. “We’re trying to establish the baseline of healthy human flatulence patterns, including how many times a day people fart and what foods are the major causes.”
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