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.

How fecal transplants work

1,700 years ago, Chinese alchemist Ge Hong was renowned for his soup that could cure diarrhea-stricken patients. It had a surprising secret ingredient: feces. While it might seem unwise to consume feces, exciting new research suggests that taking...

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

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

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

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.

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.

Some dementia cases may be linked to treatable microorganism infections in the brain.

Exercise causes diet-independent changes in the gut microbiome.

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

Specific gut microbiome 'fingerprints' are associated with cancer recurrence, with up to 94% accuracy.

Hookworm infection, though risky, may help fight certain health conditions.

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

Fungi have been used to restore island habitats in the central Pacific

After removing 1.5 million invasive coconut palm trees and eradicating the black rats that fed on them, as well as seabirds and crabs, conservationists working with the US Fish and Wildlife Service identified areas where fungi could be transplanted to provide nutrients to native trees. These trees serve as nesting sites for seabirds whose guano nourishes coral reefs.

Gut microbiome rewrites may help reduce allergies

Researchers are investigating different strategies to determine if one day they could give people a combination of gut microbes to set them up for fewer allergies. In animal research, scientists have already prevented severe allergic responses in allergy-prone mice—supplying them with gut microbes from healthy, non-allergic human babies.

Without the option of modern blood transfusions, some doctors in the mid-1800s tried to help save cholera patients by injecting them with cow's milk, hoping it would boost their nutrition and hydration.

Why bacterial bioremediation may help counter the negative effects of past chemical solutions

Molecules such as DDT, a synthetic insecticide, and PFAS—"forever" chemicals used to make products resistant to heat, water, and grease—have historically been used across various industries but are now known to be harmful. Microbes that can convert some of these substances into nontoxic products, such as water and carbon dioxide, have already been identified, with ongoing research to find others.

Examining the potential of the emerging field of insect-based bioremediation

Also known as entomoremediation, the novel approach uses larvae and adult insects, including their gut microbiomes and associated enzymes, to extract or degrade pollutants. As of 2025, research has shown that black soldier flies can degrade a wide range of antibiotics, highlighting their potential for bioremediating antibiotic-contaminated organic waste.

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.

Recombinant DNA technology turns microorganisms into protein factories

Genes for molecules such as insulin can be inserted into loops of bacterial DNA called plasmids and reinserted into bacteria. Once placed in fermentation tanks, these bacteria use the gene to produce these molecules, which are then harvested and purified for eventual use.

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.

Cross-species transplantation has been attempted in medicine for more than 300 years.

Gene therapy can occur inside the body, but it can also be completed outside the body—with scientists treating cells in the lab, and then those corrected cells are transplanted back into the body.

Learn how environmental conditions are optimized to increase bioremediation efficacy

Through biostimulation, Indigenous microbes are provided with moisture, nutrients, or oxygen to prevent their death and ensure optimal progression of their biochemical reactions. Bioaugmentation can introduce new microbial cultures to target specific compounds not natively found in the environment, while landfarming can spread or aerate contaminated soil to improve access to contaminants.

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.

Pooping or puking out pathogens is sometimes recommended with food poisoning

Sometimes stopping food poisoning-linked diarrhea with over-the-counter medications is a bad idea because it may prolong illness. Doctors can advise you if your diarrhea or vomiting is severe about what medications to take and when, but generally doctors recommend trying to stay hydrated during a bout of food poisoning and letting the body naturally remove pathogens from the body via vomiting or diarrhea, as needed.

‘Hope for Healing’: The first-ever use of an in utero stem cell treatment

In 2023, researchers at UC Davis performed the first-ever fetal stem cell transplant, attempting to cure a case of spinal bifida prior to childbirth using stem cells derived from the placenta. The trial, and others including an effort to treat muscular dystrophy, highlight the potential power of stem cell therapy.

Research suggests the cleanliness of the ISS may make astronauts unhealthy

The International Space Station's sterile conditions deprive astronauts of the opportunity to strengthen their immune systems through microbial exposure. To address this problem, future missions may use probiotic-based cleaners and foster diverse microbes in space habitats.

In 1892, two scientists purposefully infected themselves with cholera bacteria

When they became ill—one with mild diarrhea and the other with severe cholera—researchers pointed to that as proof that the pathogen caused the disease.

How scientists are using molecules found in acidophiles to develop new medical treatments

The Berkeley Pit, an open-pit copper mine in Butte, Montana, that ceased operations in 1982 and is now filled with highly acidic water, is home to various species of fungi and yeast. These extremophiles produce unique compounds that may have anti-inflammatory benefits and have already been used to create an antibiotic for staph infections.

Learn how cholera bacteria sicken humans

Once a person has ingested large amounts of the bacteria, typically through contaminated water, cholera bacteria begin producing and releasing a toxin inside their host. It attacks the mucosal lining of the intestine, making it hard to absorb liquids. This process leads to cholera's characteristic symptoms, like voluminous, watery diarrhea.

Dr. Henry Heimlich, famous for his antichoking technique from the 1970s, was a proponent of controversial and discredited approaches, including infecting cancer and HIV patients with malaria to try to trigger a heightened immune response.

Explore different pig-to-human xenotransplantation possibilities, including using pig pancreatic cells for treating diabetes.

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.

Neglected tropical diseases affect more people than the population of Europe

This group of conditions, which includes hookworm, sickens roughly one in seven people on the planet—a tally which dwarfs Europe's population of roughly 450 million. International cooperation and donations are helping to control some of these illnesses, which can be caused by parasites, viruses, and bacteria. They're all treatable or preventable, but primarily occur among poor, isolated communities that may not receive adequate care.

A clinical trial is underway in 2026 to help kidney transplant recipients avoid a lifetime of immunosuppressing drugs

This later-stage clinical trial, in Chicago and Taiwan, evaluates the efficacy and safety of a new cellular therapy that may be swapped in for immunosuppressing drugs among kidney transplant recipients. The study randomizes people to either receive standard immunosuppressants or this cellular therapy and fewer immunosuppressants. It only includes kidney transplant recipients receiving organs from live donors so transplant surgery timing won't hinge on the unpredictable schedule of performing surgery and follow-up care when a donor dies.

Stem cell therapy has shown promise in treating spinal injuries in an early-stage clinical trial.

Researchers are investigating how altering the gut microbiome may influence the development of rheumatoid arthritis, which is an autoimmune disease.

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.

Immunosuppressants enable organ transplants, but come with severe side effects

This drug cocktail helps to lower your body's natural response to attack a transplanted organ. Such medications usually need to be taken for a lifetime after receiving an organ and can come with serious side effects including high blood pressure, diabetes, increased risk of some cancers, and high cholesterol, among others.

The gut microbiome may play a major role in autoimmune disease and symptom flare-ups

Certain unhealthy foods can promote gut bacterial growth and inflammation in the lining of the gut, potentially disrupting its lining—leading to a leaky gut that may allow pathogens to dribble out into the bloodstream, fueling further inflammation that can both cause disease flare-ups and set the stage for future disease development.

Pig-to-human transplant work has raised concerns about donor pigs' living conditions.

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.

Xenotransplants are an experimental last resort for the terminally ill when they cannot or will not receive a human organ.

View a breakdown of bioremediation strategies, divided into onsite and offsite options

Depending on the contamination's complexity, in situ—onsite—options may be preferred and can include supplying oxygen or nutrients into the existing soil to accelerate the microbial breakdown already present in the environment. Ex-situ methods instead displace contamination for treatment away from the environment and may be used for volatile chemicals that require isolation, though this displacement can also spread contaminants if spilled.

A scientist successfully treated her own breast cancer by injecting the tumor with lab-grown viruses.

About 20% of people infected with cholera have severe symptoms

That's according to studies from outbreaks in Bangladesh. Most people who contract the disease have mild or moderate symptoms, or none at all. Yet anyone infected with the disease-causing bacteria can shed the pathogens in their feces for a few days, or even up to around 10, seeding the environment with bacteria.

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.

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.

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.

CRISPR allows scientists to cut out and replace faulty or unwanted DNA, which can help treat genetic disorders, such as sickle cell disease, and create genetically modified organisms, such as allergen-free foods.