The University of Maryland research team describes its device as Smart Underwear designed to measure human flatulence. The wearable tracks hydrogen, a gas produced when gut microbes ferment fiber and other carbohydrates that are not fully digested.
The findings do not mean people can diagnose themselves by smell alone. But they add to a growing body of research suggesting that intestinal gas is more than an embarrassing side effect of digestion. It may be a real-time signal of microbial activity inside the gut.
What may reveal about gut health
Most intestinal gas is odorless, but the foul smell often comes from sulfur-containing compounds, especially hydrogen sulfide. In small amounts, hydrogen sulfide plays biological roles in the body. In larger or poorly regulated amounts, researchers have linked it to irritation, inflammation and digestive disorders.
A 2025 paper on long-term monitoring of gut microbial gas production via flatus reported that the wearable sensor detected diet-driven changes in microbial activity. That matters because stool samples and clinic-based breath tests only capture snapshots, while gas production changes throughout the day.
Hydrogen and methane already have a place in digestive testing. A 2025 study found that hydrogen sulfide and methane on breath testing correlate with stool microbial populations, strengthening the idea that gas measurements can reflect differences in the gut microbiome.
Researchers say the promise is not in one smelly episode, but in patterns. Repeated gas measurements could one day help show how a person responds to fiber, dairy, high-sulfur foods, fermentable carbohydrates or treatment for suspected digestive conditions.
Why odor alone is not a diagnosis
Digestive gas can change because of diet, swallowed air, medications, constipation, infection, food intolerance or shifts in gut bacteria. The National Institute of Diabetes and Digestive and Kidney Diseases explains how digestion works by breaking food down, absorbing nutrients and moving waste through the intestines.
The colon plays a major role in turning food waste into stool, absorbing water and housing many gas-producing microbes. The Cleveland Clinic’s overview of the large intestine notes that problems in this part of the digestive tract can contribute to common issues such as constipation and diarrhea, as well as more serious disease.
That is why experts urge caution. A rotten-egg smell may point to sulfur compounds, but it does not prove someone has irritable bowel syndrome, inflammatory bowel disease, small intestinal bacterial overgrowth or any other condition.
Earlier research shows this gut health story has been building for years
The idea that smelly gases may have medical meaning is not new. In 2014, a TIME report on hydrogen sulfide research described early work on whether small amounts of the gas could protect cells from damage.
By 2017, specialists were already working to standardize gas-based testing. The North American Consensus on hydrogen and methane breath testing concluded that breath testing can be useful for evaluating common gastrointestinal problems, including carbohydrate maldigestion and suspected small intestinal bacterial overgrowth.
In 2023, the American Society for Microbiology published a plain-language review asking what role hydrogen sulfide plays in the gut. The article noted that the same compound responsible for a rotten-egg odor is involved in processes that may support health or contribute to disease, depending on context.
What the breakthrough could mean for patients
The newest work points toward a future in which digestive symptoms are tracked more continuously and objectively. Instead of relying only on memory, food diaries or occasional lab tests, researchers may be able to compare gas patterns with meals, symptoms and microbiome data.
That could be especially useful for people with recurring bloating, excessive gas, abdominal pain or suspected food intolerances. A device that shows when gas spikes after specific meals could help clinicians ask better questions and design more personalized diet trials.
For now, the technology remains a research tool, not a home diagnostic product. People should seek medical care if gas comes with unexplained weight loss, blood in stool, persistent diarrhea, vomiting, fever, severe abdominal pain, anemia or symptoms that wake them at night.
Smelly farts are not automatically a warning sign, and they are not a medical test by themselves. But scientists are increasingly treating intestinal gas as a useful clue rather than a joke.
If future studies confirm the early findings, flatulence monitoring could become part of a broader approach to gut health — one that links diet, microbes and symptoms in real time.
