A groundbreaking journey into the fascinating micro-universe in our mouths, and how to care for the ecosystem that’s been caring for you all along

The mouth is your body’s front door—and yet, we’ve been taught to think of it as something to scrub, drill, fill. But what if your mouth isn’t something to fix but rather a universe that is crowded, chatty, and astonishingly alive?

Right now, billions of microbes are living on your teeth, gums, tongue, and in your saliva. They are working, fighting, cooperating, sending signals, shaping inflammation, influencing digestion, and helping determine whether your body moves toward resilience or disease.

In Spit, board-certified dentist and oral microbiome pioneer Dr. Staci Whitman pulls readers into this wildly underexplored universe and presents the new science and surprising links between the microbial menagerie on your tongue, teeth, and tonsils to dementia, fertility, diabetes, heart disease and cancer.

Spit is the answer.

Transforming complex science into a thrilling road trip through our bodies, Dr. Whitman delivers a new and pioneering map for improved health and longevity. Along the way we meet patients that bring the mouth-body connection to life, like Jessica, whose offhand mention of longstanding migraines during a dentist appointment prompted imaging that traced them to a hidden infection, and Peter, whose chronic bad breath led to a diagnosis of fatty liver disease.

Beyond the science and stories, Dr. Whitman outlines clear lifestyle changes and need-to-know facts like:

• "Eat a rainbow" of foods to feed your good bacteria
• Slow down your chewing to increase saliva, aid digestion, and give food time to interact with oral microbes
• Saliva isn’t just water or waste; it buffers acids, supplies minerals that repair enamel, and carries information about stress, hormones, and microbial balance
• Ultra-processed foods, sugary sodas, polluted air, and chronic stress have crowded our teeth, shrunk our faces, and altered our saliva dramatically, increasing our risk of stroke, heart disease, and potentially Alzheimer’s
• Your mouth is a neighborhood, not a battlefield: the objective isn’t a germ-free mouth, but a diverse, strong, resilient community that doesn’t allow opportunistic microbes to take over

When it comes to whole-body health, mouths do a lot of talking. It’s time we listen.