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• Posted March 7, 2026

Can The Critters in Your Mouth Cause or Cure Disease?

SATURDAY, March 7, 2026 (HealthDay News) — No matter how much you brush, floss and rinse, there’s a zoo colonizing your teeth, gums and tongue.

Billions of microscopic critters called microbes make their home in your mouth, and scientists studying them suspect they play important roles in not only diseases of the mouth but also those elsewhere in the body. 

They hope learning more about what they call the "oral microbiome" might point them to new ways to head off or treat many illnesses, NIH News in Health reports.

"People tend to have certain microbes in specific proportions," said Akintunde Emiola, who studies these organisms at the National Institutes of Health. "When that proportion changes, that can be linked to diseases."

An example: Eat too many sweets, and sugar-loving bacteria that live in the plaque dentists scrape off your teeth can wreak havoc. 

The zoo in your mouth has also been linked to diseases in other parts of your body — from cancer and heart disease to allergies, asthma and even Alzheimer’s.

In all, the human mouth is home to about 700 species of microbes, scientists have found. Some help keep disease-causing species from taking over. Others may contribute to disease. 

Figuring out which do what and how changes in the population of your oral microbe population is a focus of ongoing NIH research.

In one ground-breaking discovery, Colin Combs, an expert in neurodegenerative diseases at the University of North Dakota, and his team have identified a substance linked to Alzheimer’s disease in saliva.

"We think the type of bacteria that live in the mouth might secrete substances that can get into your bloodstream, go into the brain, and cause things to go awry," Combs told NIH News in Health. 

His team is researching how beta amyloid in saliva affects mouth microbes — and vice versa. 

Beta-amyloid is the sticky substance that clumps together in the brain into the sticky "plaques" that are a hallmark of Alzheimer’s. 

They’re also trying to figure out whether beta-amyloid in the mouth plays a role in Alzheimer’s.

Meanwhile, Christian Abnet is part of an NIH team investigating whether oral microbes may play a role in some cancers. 

One theory: Certain bacteria may produce carcinogens, which are cancer-causing substances. His research has linked certain mouth microbes to an increased risk for cancer in the colon, esophagus and lungs.

The makeup of your oral "zoo" may also trigger changes in the way your immune system responds to germs. 

"Figuring out the mechanisms is really important if you want to design an intervention," Abnet said.

But chasing away disease-causing microbes isn’t as easy as brushing, rinsing, swishing and spitting — or getting a prescription antibiotic.

While antibiotics kill microbes, today’s versions don’t just affect the bad ones. Emiola’s lab is trying to develop ways to destroy the disease-causing bugs, but not the beneficial ones.

"When you kill all of the microbes, the problematic ones tend to repopulate faster," he told NIH News in Health. "But if you specifically target the bad microbes, that allows the good ones to repopulate the environment."

Emiola’s team is trying to develop targeted medications that zero in on the bad bugs.

They’re relying on treatments known as "prodrugs" — compounds that become active only inside specific bacteria. The approach has already resulted in a prodrug that takes out bacteria that cause severe gum infections. 

Emiola thinks the approach could someday help treat diseases outside the mouth, too.

Meanwhile, grocery stores are filled with supplements touted for their ability to make the microbiome healthier. Prebiotics encourage the growth of certain microbes; those microbes are already contained in probiotics. 

But researchers don’t know for sure which microbes or combos are effective. 

"Maybe one day we’ll have [microbiome-based treatments that are] beneficial to people," Abnet said. "But we’re in the early days of that research right now."

As research continues, here are some ways to promote a healthier oral microbiome:

• Avoid tobacco products, including e-cigarettes.

• Drink less alcohol.

• Eat a healthy diet and stay away from added sugar.

• Brush and floss at least once a day and see your dentist regularly.

More information

Learn more about the links between oral health and overall health at the Mayo Clinic.

SOURCE: NIH News in Health, March 2026