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

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 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 bacteria in the gut, and maintaining the relative balance of microbes in this ecosystem is important for our health.

Researchers generally group gut bacteria into six different categories

The trillions of bacteria in the gut microbiome can be grouped into six categories: firmicutes, actinomycetota, pseudomonadota, fusobacteriota, bacteroides, and a broad miscellaneous category. The functions of each are complex but range from breaking down food and producing vitamins to fighting pathogens.

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.

How to maintain a healthy gut

Approximately 40 trillion microbes reside in the human gut, forming a unique microbiome, containing hundreds of millions of neurons in what is often called a "mini-brain". A healthy gut is characterized by an effective mucus-lined barrier that prevents unwanted substances from entering the bloodstream. So how do you attain such an ideal gut? This guide outlines a healthy approach to protecting your gut.

Some animals, including certain tropical ants, have little or no bacterial populations in their gut, upending the idea that all animals rely on such microbes 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.

Gut microbiome experiments involving transfers of gut microbes from depressed people to rodents indicate that the rodents may then display depression-like symptoms, underscoring that gut microbes may influence behavior and personality more than previously known.

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.)

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.

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.

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.

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.

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.

Exercise causes diet-independent changes in the gut microbiome

Cardiovascular exercise has been found to boost the gut's population of beneficial bacteria, and exercise overall decreases the likelihood of developing a "leaky gut," a condition in which a porous gut lining allows bacteria to leak into the bloodstream and cause inflammation.

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.

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.

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.

The gut microbiome's role in chronic diseases

Research shows that the microbial makeup of one's gut microbiome is associated with chronic diseases ranging from asthma to schizophrenia. Understanding these associations may reveal new ways to prevent or treat chronic diseases. In the meantime, nutritional changes—such as including more dietary fiber and unsaturated fat—appear to be the "most obvious, noninvasive, and immediate" way to alter the gut's microbiota makeup and functions.

Are probiotics a scam?

Probiotics are microbes meant to benefit the gut microbiome's health when consumed. This internal cityscape is packed with thousands of species of microbes whose roles and impacts have yet to be untangled. The odds are low that the probiotics have the effects they're marketed to have, and most of the gut helpers on grocery shelves have little to no evidence of impacting gut microbiome health.

Some dementia cases may be linked to microorganisms in the brain

Researchers now know that, much like the gut, the brain is home to an ecosystem of microorganisms—the brain microbiome. While this area of study is still new, some scientists believe 50% of bacteria-caused dementia cases could be treated. (Some users may encounter 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.

Bacteria in our intestine influence the brain via the gut-brain axis. (Paywall may apply.)

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

The American Gastroenterological Association in 2020 concluded that although almost 4 million American adults have taken some form of probiotics, health claims about them are not backed in strong evidence. They only recommend their use for a few specific situations: to prevent Clostridioides difficile infection in people taking antibiotics that kill gut bacteria, to prevent necrotizing enterocolitis in preterm infants, and for the management of a complication of inflammatory bowel disease called pouchitis.

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.

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.

The marvels of mucus

Mucus—otherwise known as snot or phlegm—has a gross reputation, but the substance is actually of vital importance, lining the moist surfaces of our nose, intestines, lungs, and more. It plays a constant role in keeping our tissues from drying out and acts as a line of defense, but if it gets too sticky or thick, it can cause problems. Read about the marvels of mucus here.

Fungi make people sick when they invade and survive in otherwise healthy human tissue

We breathe in airborne spores frequently, but they often don't make us sick. This video details how certain concerning fungal changes can occur and discusses the role of mycologists—scientists who study fungi—in helping to improve human health.

It is impossible for astronauts to burp in space

Due to Earth's gravity, liquids and solids sink in our digestive system, while gases rise, allowing them to be forced back up the esophagus to be expelled through burping. In the microgravity environment of the International Space Station, burping would result in vomiting if it were possible.

Feeding grazing cattle seaweed cut their methane emissions by almost 40%

The largest share of the 12% of global greenhouse gas emissions from livestock comes from methane released when cows burp. A study found that introducing a seaweed supplement in pellet form significantly reduced these emissions without affecting cattle's health or weight.

What constitutes a 'healthy' diet?

A natural diet, typically high in plant-based foods and low in processed foods, appears to be the main contributor to a healthy, diverse gut microbiome.

The amount of plastic chemicals in 300 everyday Bay Area foods

Food production is more complicated than it appears, and manufacturing, packaging, and shipping processes can add significant substances to your food. This massive project compiled data on 300 samples of foods delivered to the San Francisco area, testing for the presence of 18 different kind of plastic. Learn how to read the data here with its helpful guides and then explore the table yourself.

An anthropologist spent years riding garbage trucks to understand what our trash says about us

Robin Nagle rode with New York City sanitation workers to trace the hidden life of what we throw out. Her research explores what the things we discard reveal about who we are. 1440 explores the hidden life of trash.

Research links the gut microbiome and rheumatoid arthritis

Arthritis is a potentially disabling joint condition that currently affects nearly one in five adults across the globe. Doctors still don't know what causes rheumatoid arthritis, but the answer may be partly determined by chemicals produced by bacteria in the gut.

Can the gut microbiome drive addiction?

New research suggests an imbalance of gut microorganisms may influence the likelihood of addiction and addictive behaviors by increasing the severity of withdrawal symptoms, triggering brain inflammation in regions of impulse control, and more.

Methane leaks during natural gas processing reduce the gas's overall cleanliness

Natural gas is advertised as a cleaner fossil fuel because it emits 50% less carbon dioxide than oil and coal when burned. Supporting analysis only considers end-use combustion and excludes total emissions generated by extraction, shipping, and processing.

Carbon dioxide is the most produced greenhouse gas from human activities

In 2022, about 79.7% of US greenhouse gas emissions were carbon dioxide, produced through chemical reactions in processes such as cement production and the burning of fossil fuels, solid waste, trees, and other biological materials. Methane (11.1%), nitrous oxide (6.1%), fluorinated gases (3.1%), and trace amounts of solid and liquid aerosol were also created.

Bacteria have been genetically engineered to bioluminesce when wine has spoiled

Developed by researchers at Hebrew University, the method involves the firefly enzyme luciferase, which emits light from within bacteria expressing when they are in the presence of acetic acid vapors produced by wine. The process provides affordable, on-site, real-time monitoring of fermentation quality.

Despite privacy risks, scientists are using DNA in the air to assess ecosystem health

While DNA in soil and water samples has long been used for such analyses, airborne DNA is being incorporated into such efforts to monitor individual species abundance, detect invasive species, measure biodiversity, and determine the success of conservation actions. Future work may include detecting attacks from biological weapons.

Why breathing helium, sulfur hexafluoride, and other gases changes your voice

The speed of sound varies depending on the properties of the material it travels through, including its density. Because helium is less dense than air, sound travels faster, altering the timbre of one's voice to be squeakier by enhancing its higher frequencies. In molecules that are heavier than air, low-frequency sounds are enhanced, producing a deeper voice.

The history of Earth's breathable atmosphere, made possible by photosynthetic bacteria

Between 3.2 billion and 2.8 billion years ago, threadlike microorganisms called cyanobacteria began consuming available water vapor, carbon dioxide, and sunlight to produce oxygen. However, molecules released from Earth's interior by volcanoes consumed this oxygen via chemical reactions, preventing it from accumulating until volcanism had sufficiently decreased about 2.4 billion years ago.

Solutions of bioluminescent bacteria can create FOMO-inducing living art

A 2002 exhibition at Montana State University-Bozeman placed the bacteria onto petri dishes that served as macroscopic pixels to create images. Once the bacteria finished eating all the food in the sealed dishes, the light slowly faded away, ending the exhibit.

Fluorinated molecules are the most impactful, longest-lasting greenhouse gases

Developed as replacements for ozone-depleting substances in refrigeration and air conditioning systems, these compounds are released through leaks in and ongoing use of these appliances, as well as from various industrial processes. They can remain in the atmosphere for thousands of years and have warming potentials that are a thousand to tens of thousands of times greater than those of carbon dioxide.

How microbes limited the damage and helped clean up the Deepwater Horizon oil spill

A bloom estimated to contain about 100 sextillion microbial cells broke down much of the 4.1 million barrels of spilled crude oil into nontoxic compounds in what was one of the most significant bioremediations of a human-made disaster. The microbes involved acted similarly to the first patented genetically modified organism in US history: an oil-eating bacterium engineered in 1971.