Farts are tiny status reports from our gut microbiome, with American adults typically passing gas more than 30 times daily.

Scientists seeking gut insights are attaching flatulence sensors to volunteers' underwear

This fart-tracking device detects gas generated in the gut, providing insights about gut microbial activity. The underwear sensors measure a component of what is technically called flatus—digestive system gas.

On the benefits of 'fart walks'

Walking has proven benefits for flatulence by kickstarting the process of peristalsis in the bowels and facilitating easier farts and burps. The timely exercise is also correlated with weight loss (as well as potentially reduced opportunities for social embarrassment).

Researchers generally group gut bacteria into six different categories, with varying amounts of these microbes residing in different parts of the digestive tract.

The gut microbiome—a complex community of up to 100 trillion microbes—has a changing composition, influenced by our life stage, diet, medications, environment, and other factors.

Trillions of bacteria, viruses, fungi, protists, and archaea live in our guts, producing a wide range of molecules, hormones, and more—underscoring the immune system's pivotal role in the microbiota-gut-brain axis.

What is the gut microbiome?

The gut microbiome is a microscopic ecosystem that runs off the work of microbes in the digestive tract. These workers make getting energy from food possible. What and how that energy manifests depends on what building blocks these microbes have to work with, meaning their composition and functions are strongly influenced by diet. Gut microbes have their own genes, which affect how a person's genes act.

There are up to 100 trillion microbes in the gut, and maintaining the relative balance in this ecosystem is important for our health.

Explore the chemistry of undesired body odors

This graphic highlights some of the main compounds in different body odors, including halitosis (bad breath), flatulence, and foot odor.

Benjamin Franklin once wrote a satirical essay about passing gas

The Founding Father was asked to judge a contest for the Royal Academy of Brussels, but was incensed by one of the contest's questions, which he believed was highly impractical. In response, he wrote a piece suggesting that the most essential problem for scientists to solve was the "fetid Smell" that came with passing gas.

In 2026, University of Cambridge researchers reported that a group of gut bacteria called CAG-170 may be a key marker of good health, occurring far more often in healthy individuals and less commonly in people with chronic diseases.

Gut bacteria are evolving and can acquire as many as 100 new genes per year, on average.

Corynebacterium species are particularly responsible for our funky smell

Myriad bacteria contribute to our body odor, but research suggests that Corynebacterium species are strongly associated with the bad smells emanating from adults. Staphylococcus and Cutibacterium genera may also play leading roles.

Some animals, including certain tropical ants, have little or no microbial populations in their gut, upending the idea that all animals rely on this ecosystem to help maintain their health and proper functioning.

What's next for gut microbiome science?

A Stanford microbiologist explores what we don't yet know about the gut microbiome—such as whether we can engineer the bacterial species within it—and the current scientific advances in the field.

Visualize the different parts of the digestive tract, a roughly 30-foot tube which runs from our mouths to our rear.

The reason some people love exercise may be because of their microbiome

Certain gut microbes in mice trigger dopamine release and drive motivation to exercise more. Scientists are investigating whether humans carry similar microbial patterns that influence our natural inclination towards movement, exploring how unseen microbial ecosystems may shape mammalian fitness behavior and reinforce innate reward pathways. (Some users may experience a paywall.)

Gut microbiome experiments involving transfers of gut microbes from depressed people to rodents indicate that the rodents may then display depression-like symptoms.

A technical review of what researchers know about the gut microbiome

This overview from the National Institutes of Health provides a deeper (but still accessible) look at the different bacteria in the gut, how the microbiome develops through life, its purpose, and more.

Scientists have found that the Great Barrier Reef's microbiome includes an estimated 362,802 distinct viruses and 876 distinct bacterial and archaeal species—584 of which had never been documented before 2026.

Listen to how the gut microbiome influences your emotions

The gut-microbiome connection may involve the enteric nervous system, a collection of hundreds of millions of neurons throughout the gut that transmit signals up the vagus nerve to the brain.

Watch a visualization of New York City's greenhouse gas emissions

About 1.72 tons of carbon dioxide-equivalent gases are released into the atmosphere every second in the Big Apple, enough to fill a balloon 33 feet across at standard pressure and 59 degrees Fahrenheit. After a day, the spheres would pile up into a pyramid whose base spans from the bottom of Manhattan to the south of Central Park.

Listen to recordings of different fish species

Scientists have captured and curated this collection of species-specific recordings, helping us gain a deeper understanding of underwater ecosystems. Uncover their sounds, which include a lot of thumps, burps, and grunts.

Food passes through the digestive system via muscle movement known as peristalsis, a rippling contraction that pushes food onward through tubular organs.

Landfills capture methane gas and convert it into usable energy

As organic waste breaks down underground, it produces landfill gas that is roughly 50% methane. That gas can be captured and used to generate electricity or provide heat for nearby homes and businesses.

Odor blockers use nonpolar oils to trap smelly polar molecules

In the case of feces, gut bacteria produce compounds such as skatole and hydrogen sulfide, which the brain registers as unpleasant. Because oils do not dissolve in water, they can be used to create a layer on the surface that prevents smelly compounds underwater from escaping into the air.

How the microbiome affects your health

The gut microbiome is so influential to overall human health that some researchers consider it a separate organ. Its conditions, influenced by environmental and lifestyle factors such as medication and exercise, contribute to immunity, metabolism, inflammation, medical treatment efficacy, brain development and function, and the development of disorders and diseases, including asthma, depression, inflammatory bowel disease, and Alzheimer's.

Vitamin B1 is linked to gut motility—helping fight constipation—in 2026 research

A study published in early 2026 found a link between vitamin B1 and the successful movement of food through your GI tract, known as gut motility. The work incorporated genetic and survey data about poop frequency to identify genes associated with gut motility and then separately linked poop frequency data with how much vitamin B1 people ingested, theorizing that the vitamin supports the production of acetylcholine, a neurotransmitter that stimulates GI system contractions.

How humans digest food

Every day, the average human eats close to six pounds of food—all of which must be processed by the digestive system. Ten organs collaborate to transform food that the mouth chews into the energy needed to stay alive. (Stretched out, these organs...

Food poisoning investigations have led to more than 1 billion pounds of food recalls

PulseNet is the US government’s real-time foodborne illness tracking system for leading causes of food poisoning. There, a network of labs and scientists share DNA sequences for pathogens collected from contaminated food and also from sickened individuals, looking for patterns in the pathogens’ genome sequences that will help them hopefully finger a certain food, warehouse, producer, or restaurant.

There's an official term for the sound your stomach makes before intense diarrhea

It's borborygmi. The sound is produced when gas or liquid moves through the bowel. Peristalsis, the wave-like muscle tightening process that typically pushes food through the digestive system, produces the sound as it tries to push these substances through the body.

Most people breathe fungal spores daily without getting sick

Most people breathe in hundreds of Aspergillus fumigatus spores daily without getting sick—it’s a common microscopic fungus in our environment. But people who are severely ill, including those who have undergone an organ transplant, are at risk of developing infections from these spores.

What is a microbiome (and why are they important)?

Jump to: What is the microbiome? How microbiota benefit the body The role of probiotics Can diet affect one’s microbiota? Future areas of research What is the microbiome? Picture a bustling city on…

Fecal transplants can help treat infections by transplanting healthy gut bacteria from a donor into a patient's gastrointestinal tract using samples of human waste, which are turned into a liquid mixture and often delivered via a colonoscopy procedure.

Bacteria in our intestine influence the brain via the gut-brain axis.

The food industry's hard-to-solve pollution

One-quarter of the world's greenhouse gas emissions result from food and agriculture. That whopping number includes production and post-farm processes like distribution. See a visualization of the data along with a breakdown explaining how each process contributes to emissions, and why it’s so difficult to improve the agriculture industry.

Exercise causes diet-independent changes in the gut microbiome.

Humans may be able to distinguish more than one trillion scents

That's according to one estimate published in 2014. This figure far exceeds earlier estimates of a human smelling ceiling around 10,000 odors. The newer figure is derived from experiments in which volunteers agreed to sniff varying scents. Researchers mixed odor components and had volunteers sniff the brews to detect subtle scent differences. (Some users may experience a paywall.)

America generates more trash per person than any other country on Earth

The US produces roughly 292 million tons of municipal solid waste per year, about 4.9 pounds per person per day. Municipal solid waste includes food scraps, packaging, electronics, yard trimmings, and more. About 50% of the waste ends up in a landfill.

What happens when the gut microbiome is out of whack?

An imbalance in gut microbiome flora can lead to a condition known as dysbiosis. This condition is typically characterized by a drop in microbiota diversity and an increase in harmful unicellular and acellular organisms, such as viruses, that can negatively impact the host's immune system and overall health. Genetics, infections, dietary choices, antibiotics, food additives, artificial sweeteners, and other lifestyle and environmental factors can cause dysbiosis.

Scientists determine the smells of objects in outer space

Using spectrographic techniques, scientists determine the chemical composition of planetary atmospheres, comets, and other objects in space. Combining these chemicals in labs on Earth has revealed locations in space that smell like nail polish remover, rotten fish, and urine.

A dog's nose can be up to 100,000 times more sensitive than a human's, and each possesses a secondary organ for smelling, which helps learn about other dogs when they sniff each other's butts.

Microbes are essential to creating the many varieties of cheese, influencing texture and taste

Microbes break down proteins and fats and produce compounds with distinct tastes. These microbes can include bacteria (like the one used to give Swiss its trademark holes), molds (like the ones that give blue cheese its distinctive veining), and countless other tiny organisms.

Probiotics, which are living bacteria and yeasts, are not recommended for most patients.

See how the gut and the brain communicate through a bundle of nerves running from the brain to the digestive tract, serving as both a physical and chemical link.

A doctor answers the internet's burning questions about the gut

Gastroenterologist Dr. Ugo Iroku answers the internet's burning questions about digestion and bowel movements. Get the lowdown on what it means when your stuff is super dark, the impact of coffee on evacuating bowels, and much more.

Humans can track smells on the ground quite well—our ability to crawl is a limiting factor

As part of a scientific bet, neurobiology researchers dragged a chocolate bar across the grass and sought to see if a human could track it—she could. This led to a more in-depth experiment on human olfactory capabilities and behavior when other senses were blocked.

1 in 15 adults over age 40 experience phantom odors

This phenomenon was measured in a 2018 study that examined the prevalence and risk factors for phantom odor perception. Older adults were less likely to experience these phantom odors as they age, just as their overall sense of smell declines. Women are more likely than men to perceive phantom odors.

A 'fishy' scent does lead to mistrust

In experiments where people were exposed to a literal fishy smell they were less willing to cooperate with others in economic games requiring trust, but that wasn't the case when they were exposed to another bad odor—the smell of flatulence.

A 2025 study explored the common words to describe body odor across 17 countries

The work identified the 25 most frequent words used to describe body odors across languages, ranked by frequency, and found that "sweaty" topped the list, followed by "sour" and "stinky."

Yearly greenhouse gas emissions have been steadily increasing since 1850

Although greenhouse gases include methane, nitrous oxide, and most fluorinated compounds, their warming potential is often measured relative to carbon dioxide. In these units, greenhouse gas emissions have gone from 4.29 billion metric tons of carbon dioxide equivalent in 1850 to 54.43 billion metric tons in 2024.