About the Microbiome

Meet Your Microbes

Many kinds of microorganisms live in and on your body. Meet some of your "tiny tenants" up close.


Some fungi live on your skin. Hundreds of different kinds grow on your feet. Others live in your stomach and help with your digestion.


Bacteria have many important functions in your body. We often think of them as "germs," but most are harmless, and many are essential to your health.


Archaea live in your gut and help you digest food. They produce the methane in your farts.


Viruses invade living cells to reproduce. Some attack your down cells. Others attack bacteria, and help keep the microbes in your body in balance.

Your Body is a Habitat

For every one human cell in your body, there are ten microbes. What’s your inner life like?

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Most of the microbes in your body live in your gut. The balance of your gut microbes can affect other parts of your body, including your brain!

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Every surface of your mouth—teeth, tongue, and the inside of your cheeks—has its own community of microbes.

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Microbes from the environment enter your nose with every breath. The flow of your snot traps microbes and washes them away.

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The high diversity of healthy microbes on your skin protects you against dangerous germs.

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Birth Canal

The vagina has a few dominant species of microbes, which defend the body against disease. During birth, healthy microbes coat the new baby.

Meet the Scientists

We have a lot to learn about the human microbiome. Meet some of the scientists who are exploring how our microbes affect our health.

Karen Nelson, Ph.D.
"Current estimates are that every square inch of skin has about one billion bacteria."
Hernan Lorenzi, Ph.D.
"So we asked ourselves, 'But how does an astronaut go to the bathroom in space?'"
Ramana Madupu, Ph.D.
Diabetes "strikes younger and younger children, and why that is we don't completely understand."