Image: This is typical of the type of marketing you’ll see for terrain theory.
Two weeks ago I reflected on an old but still relevant blog post by Peter Lipson titled Your Disease, Your Fault. His argument was simple but compelling: Alternative medicine often frames illness as personal failure. Today, that same sentiment is gaining more traction than I would have thought possible, but with new names and in new contexts. Terrain theory is making a comeback, rebranded with terms like “body sovereignty” and “internal terrain”.
According to terrain theory, germs don’t cause disease – it’s your body’s failure to maintain internal purity. If you’re healthy enough, pathogens can’t hurt you. It’s an idea with roots in reality, but goes well beyond the science of disease: terrain theory proponents ignore biology, chance, and social determinants of health. You can see terrain theory beliefs in the statements and worldview of Robert F. Kennedy Jr., who has publicly rejected germ theory. He is an open proponent of miasma theory, an obsolete 19th century idea that attributed disease to “bad air,” poor hygiene, and moral weakness. With major changes underway in health care in the United States, it’s worth taking a closer look at the language, the rhetoric, and the science.
Germ Theory vs. Terrain Theory: How One Prevailed
The germ theory of disease is foundational to modern medicine, but it wasn’t always this way. In the 19th century, two competing theories offered different explanations for why people got sick. Louis Pasteur argued that disease was caused by microbes – external pathogens, like bacteria and viruses that could invade the body and cause illness. This is germ theory. Antoine Béchamp proposed an alternative. He argued the real culprit was the “terrain”, the body’s internal environment. Béchamp’s terrain theory emphasized the importance of the body’s internal environment, suggesting that disease arises when the body’s “terrain” was weakened by poor nutrition, toxins, or stress. Only then would microbes (normally harmless) cause harm. In the Béchamp model, germs are not the issue – they are a symptom of a terrain issue.
The debate between Pasteur and Béchamp was fierce, but in the end, Pasteur’s germ theory prevailed for a simple reason: it produced dramatic results. Once scientists could link specific microbes to specific diseases, medicine was transformed. Public health measures like sanitation, sterilization, and vaccination became not just possible, but profoundly effective. Antibiotics transformed once-deadly infections into treatable conditions. Smallpox was eradicated (regardless of anyone’s “terrain”) and polio has been nearly eliminated. Childhood mortality rates dropped dramatically. Infection control became the backbone of modern surgery and hospital care. Pasteur’s model didn’t just explain disease, it led to the tools that could prevent, treat or even eliminate it. It’s worth noting that germ theory wasn’t solely the work of one man. English surgeon Joseph Lister and German physician Robert Koch are also credited for the development and acceptance of the theory.
Terrain theory, on the other hand, didn’t lead to any effective interventions. It wasn’t testable in the same way. Its vagueness made it sound plausible, but hard to act on. And while Pasteur is often quoted as accepting the importance of terrain on his deathbed, this appears more like a posthumous attempt to validate Béchamp’s ideas, than a serious statement. Even if Pasteur did make the statement, the science speaks for itself. Reality is not based on what one person says: it is based on objective evidence.
Béchamp’s ideas, while discredited, never really disappeared. Like many beliefs in alternative medicine, terrain theory beliefs didn’t arise from scientific evidence. For that reason, it’s effectively immune to being disproven by it. To be fair, modern proponents of terrain-like thinking may not even know the term “terrain theory” or the name Antoine Béchamp. But the core belief, that all disease can be avoided with the right habits, and that immunity is strictly personal, rather than something important to a population, is gaining traction.
Terrain Theory in Disguise: Recent Sightings
You might be asking why I’m arguing there’s a resurgence of “terrain theory” when that phrase itself is rarely mentioned. But once you start looking for it, you’ll spot it everywhere: The idea that a “clean” balanced internal environment prevents all disease – is everywhere.
Terrain theory underpins the raw milk movement, where the risks of pathogens are downplayed or dismissed outright because it’s believed that the healthy body can handle it. You’ll also see terrain theory in the claims that “healthy kids don’t need vaccines,” or that “food should be your medicine.” And all the detoxification, cleanses, dietary supplements, coffee enemas and IV infusions of vitamins – all are grounded in this idea that you can optimize health and eliminate the risk of disease simply by cleansing yourself from the inside out.
I’ve also recently discussed the tech-adjacent forms of terrain theory. Biohacking influencers are using glucose monitors and wearables to “promote Good Energy” and optimize your health. The vocabulary has expanded, but the unstated premise is the same: if you manage your body and its internal environment just right, you’ll be immune to external threats and illness.
Notably, terrain theory appeals to a desire for control and agency. This can be compelling to those that may be confused about how to live a healthy lifestyle, or facing a life-threatening diagnosis. And to be clear, some of what terrain theory proponents endorse may be reasonable, and even science-based. Maintaining a healthy lifestyle with a good diet, enough sleep, and regular exercise while managing your weight and not smoking can reduce your risk of chronic illness. But buying in too much to terrain theory, and discounting or dismissing germ theory has a darker implication: If you do get sick, it’s your fault. Terrain theory takes prevention and turns it into an all-encompassing worldview—one where infectious disease, chronic illness, even cancer are preventable through willpower and “clean” living.
This isn’t just bad science. Terrain theory belief creates a framework or worldview for looking at health that shifts blame for sickness on to the sick.
Body Sovereignty and the Language of Control
The idea of “body sovereignty” has gained traction over the past few years. I first heard the term when the COVID-19 vaccines were launched, and mandates were introduced. While it may sound like a simple argument for autonomy over one’s own body, when you listen to the rhetoric, it’s being used to argue against public health measures, deny science, and even reframe medical consensus and guidance as acts of oppression.
Body sovereignty accompanies terrain theory. If your internal “terrain” is all that matters for health, then external interventions—like vaccines, antibiotics, or even public health measures like fluoride in the water aren’t just unnecessary, they’re viewed as violations of your autonomy and your freedom. Public health is therefore seen as coercive: there is no need for community measures, as individuals are responsible for their own health.
This framing co-opts the language of bodily autonomy and repurposes it to reject social responsibility. “My body, my choice” becomes a rallying cry not for reproductive rights, but against vaccination. “Informed consent” becomes “misinformed refusal“, a justification for rejecting evidence-based therapies. And “health freedom” has long been a slogan for anti-vaccine activists and wellness influencers selling detoxes, supplements, and other treatments not actually shown to work. As RFK Jr. puts it,
“I’m a freedom-of-choice person…We should have transparency. We should have informed choice, and if people don’t want it, the government shouldn’t force them to do it”
Robert F. Kennedy Jr.
With a terrain theory worldview, health, and particularly public health is no longer something we need support as a society—it’s something you earn through your virtuous choices and lifestyle, or you forfeit health based on the decisions you made.
Conclusion: Germ Theory Still Matters
Terrain theory doesn’t just reject evidence: it rejects uncertainty. And in doing so, it offers an illusion of control: Live life purely and holistically, and you can avoid illness. But reality is messier. Disease can strike even the healthy. Through acknowledging the reality of germ theory, we’re also accepting a necessary truth: some aspects of our health are beyond individual control.
Germ theory gave us something terrain theory couldn’t deliver: effective, lifesaving interventions like vaccination, antibiotics, sterilization and sanitation – together they have saved many millions of lives and are cornerstones of medicine.
Healthy living matters too. Diet, sleep, physical activity, and avoiding tobacco reduce the risk of many illnesses. But when taken to extremes, which terrain theory encourages, it can lead to pseudoscience, stigmatize the sick, and undermine the public health systems and interventions that meaningfully contribute to a healthy society.
