Researchers at the University of Maryland have developed a wearable device informally known as “smart underwear” that continuously measures hydrogen released during flatulence. The purpose is scientific, not comedic: to collect objective data on gut microbial activity. For years, doctors have relied largely on estimates and patient self-reporting to evaluate excessive gas. A commonly cited figure suggests people pass gas about 14 times per day. However, in a recent peer-reviewed study, researchers reported that healthy adults averaged 32 episodes daily, with individual counts ranging from four to 59. The discrepancy likely reflects improved measurement methods, as earlier studies depended on diaries or controlled laboratory conditions. The device uses small electrochemical sensors attached to standard underwear to track hydrogen levels around the clock, including during sleep. Hydrogen is produced by gut microbes as they ferment undigested carbohydrates, making it a useful marker of microbial activity. In testing, hydrogen increases were reliably detected after participants consumed inulin, a prebiotic fibre, with high sensitivity. The research team has also launched a broader project to better define typical gas production patterns in adults, analysing results alongside dietary and microbiome data. By establishing measurable reference ranges for intestinal gas, similar to those used for blood glucose or cholesterol scientists aim to improve understanding of digestion, diet, and the role of gut microbes in human health.