Marble head of an athlete, Roman (ca. 138–192 CE), Copy of a Greek bronze statue of ca. 450–425 BCE, MET Museum New York 11.210.2
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Celsus and the Informed Patient
by James Zainaldin
by James Zainaldin
Feb. 28, 2026
Building off research from his recent book, The artes and the Emergence of a Scientific Culture in the Early Roman Empire, James Zainaldin discusses how first century CE Roman author Aulus Cornelius Celsus might provide guidance to navigate the increasing conflict between medical professionals and internet-informed patients. By examining a Roman author trying to navigate the space of amateur expertise, Zainaldan provides a template for the modern informed patient.
James Zainaldin is an Assistant Professor of Classical and Mediterranean Studies at Vanderbilt University and Faculty Associate at the Center for Hellenic Studies.
If you have kept an eye on the health-and-wellness space—the podcasts, the airport bestsellers, the wearable tech (Apple or Garmin watches, Oura rings), the lab tests you can order without a doctor—you’ve probably noticed how much medical knowledge now circulates outside the clinic.
Here’s a plausible scene in this space. After reading a book like Eric Topol’s Super Agers (2025)—a New York Times bestseller that maps the breakthroughs in early diagnostics, preventive treatment, and longevity science now reshaping how we think about aging—a patient asks her physician for Lipoprotein(a) screening or a coronary artery calcium test, wants to talk through statin options, or debates screening for Alzheimer’s risk factors such as the APOe4 gene. The physician may welcome the engagement or feel the strain of a conversation that blurs professional boundaries (especially at a time when clinical facetime is increasingly squeezed). Either way, the patient is no longer a passive recipient of care: they are informed, or at least want to be.
It is tempting to see this movement as a uniquely modern tension, a product of the internet age and the much-discussed “democratization” of expertise. Yet, the posture of the engaged, skeptical layperson has deep roots.
Mosaic depicting Asclepius’s arrival at Kos, Greece. Roman, 2nd or 3rd century CE. Asclepieion of Kos. Archaeological Museum of Kos. Photo: Archaeological Museum of Kos.
Almost exactly two thousand years ago (sometime between 20 and 40 CE), Aulus Cornelius Celsus wrote a comprehensive work called Artes (“The Arts”) that included detailed overviews of several disciplines central to the Roman way of life, including agriculture, rhetoric, warfare, and medicine. Celsus’ Artes is now almost entirely lost, except for his famous eight books on medicine (de medicina), which offer a comprehensive, elegantly written, and uncompromisingly practical account of medicine Latin for a Roman readership that included physicians and non-physicians alike.
Celsus is often remembered today as an “encyclopedist,” but his significance was much greater, as we can appreciate if we put his medical writings in their proper historical setting. These books represent a deliberate intervention into the status of medical expertise in the ancient world—and, I suggest, a model for what informed engagement with medicine might look like when knowledge moves outside the walls of the profession.
A Roman "Biohacker"?
What does Celsus’ aristocrat Roman readership have to do with today’s health-optimizing consumer? Quite a bit. Celsus’ audience included the Roman head-of-household (paterfamilias), who was responsible for the health of his family, dependents (freedmen, slaves, clients), and livestock in a world without licensing boards or the FDA. Like the modern “biohacker,” Celsus’ reader needed to be able to judge the competence of the experts he hired. And in a world where the largest part of medicine were lifestyle interventions (regimen) and the aim was—as in today’s proactive longevity medicine —to avoid illness in the first place, there were abundant opportunities for the layperson to exercise this judgment. Indeed, the Roman elite viewed the possession of a degree of personal scientific and medical knowledge as crucial to their place in Roman society. Celsus’ Artes answer precisely to this viewpoint.
Celsus begins the books on medicine by situating medicine among the artes—disciplines that were studied, admired, and deployed as part of cultivated Roman life. Thus, he introduces debates regarding the proper methodology for medicine that raged among Greek physicians of his day not as scholastic curiosities, but as stakes in an argument about what legitimate expertise looks like.
Roman mosaic, Piazza Armerina, Sicily (4th century CE
His conclusion is a balanced synthesis: reason (ratio) and experience (experientia) must be joined. This stance implies that a reader who is not a physician can still be brought into medicine’s orbit. By learning how to weigh causes, signs, and outcomes and, indeed, to reason like a physician, the layperson becomes an informed participant rather than an amateur physician. In the sphere of Greek medicine, those who pursued knowledge of medicine (but did not practice it) were called philiatroi (φιλίατροι), “friends of the art of medicine,” a group frequently addressed by the second-century physician Galen. Even Romans who did not pursue amateur knowledge quite so vehemently would likely have adopted a collaborative approach to medical care, especially because only the patient or someone close to the patient would know enough about the details of an individual’s life and conduct to calibrate regimen appropriately. (This is, incidentally, why Celsus famously claims that the best physician is one who is a “friend,” amicus, to the patient.)
Celsus’ approach resonates with the contemporary environment. There are countless “methods,” “protocols,” and “programs” for exercise, diet, and supplementation purveyed online, a push towards simplification, and a countervailing insistence on underlying mechanisms and measured clinical tests. Celsus’ intervention into the Roman environment might prompt us ask: What forms of medical knowledge are safely democratized, and which should remain decisively professional?
Sarcophagus with a Greek Physician, ca. 300 CE, Ostia, Italy. Met Museum New York 48.76.1
Regimen First: The Ladder of Intervention
One of Celsus’ most illuminating decisions is to begin with regimen, which includes what we would now think about as “lifestyle” choices: diet, exercise, sleep, bathing, seasonal habits. This was one of the three major divisions of scientific medicine in Greek and Roman antiquity, alongside pharmacology (drugs) and surgery.
Regimen is extremely complex, but it is also fundamentally transparent—at least in its effects. Its risks are generally lower than drugs or cutting, both of which the Hippocratic Oath, for example, had felt compelled to qualify, and its effects unfold over time in ways a layperson can observe. Today’s longevity and “healthspan” recommendations occupy this space: nutrition (for example, high-protein diets), cardio exercise (“Zone 2” or “Zone 5” protocols), and circadian hygiene (sleep and “readiness” scores).
A selection of ancient Roman surgical instruments, discovered at Pompeii. Pen and ink with watercolour, 19th century, Wellcome Collection 568035i
This regimen-first approach not only addresses the needs of the Roman audience, but it arguably also organizes the ancient “clinical” conversation. Celsus tacitly instructs readers to approach the medical art in stages: start with habits; adjust; monitor; escalate only as necessary. This logic mirrors the stepped intervention of modern medicine, though there is one important difference: many informed (or would-be informed) patients today feel, with or without justification, that their primary-care physician does not tell them enough about how to optimize their own “regimens” to preserve health. This may be one reason why these topics dominate the current longevity space.
Where Lay Knowledge Ends
Just as most modern, internet-informed patients are willing to recognize limits on what they can understand and perform—few people try to conduct surgeries on themselves— Celsus is not naïve about what laypeople can undertake independently. Regimen can be incredibly sophisticated: the best decision-making requires informed clinical judgment, especially when regimen is used as a first-line remedy for acute diseases (such as febrile illnesses). As the medical books continue, the subject matter becomes even more technical. Compounding and administering drugs involve a narrow safety window, and it is implausible to imagine the lay reader ever undertaking operations such as removal of bladder stones that he describes.
In one memorable portrait (Med. 7.2), Celsus describes the virtues of the surgeon—the steadiness of hand, the ability to withstand a patient’s cries without losing composure, the technical cool that comes from practice. In one way, this is another instruction to the layperson, teaching them how to evaluate a professional whose service they might engage. Yet it can also be seen as a signpost: whatever the lay reader can do with regimen, there is a threshold beyond which expertise is constituted by trained performance. In other words, there comes a point at which appreciation of the medical issues alone is inadequate: what is needed is practical know-how that comes from professional training and experience only. This is the limit that the informed patient cannot cross.
Roman Votive Offering, Wellcome Collection
Here, too, Celsus may have something to teach us. The popular consumption of medical knowledge today is provoking clashes with the medical establishment, as (scientifically) unproven advice or remedies are touted as superior to the received wisdom communicated by physicians and public health institutions. A wearable suggests an “insight,” a direct-to-consumer test offers a number, a diet video on TikTok goes viral: all these can stoke demand for interventions whose risk-benefit calculus is not obvious, or which may be applied without appropriate specificity. The current craze for high-protein diets has begun to reshape consumer habits in grocery stores and at restaurants, for example. Increased protein intake can be healthful in many situations, including to support muscle during weight loss, but it can also promote obesity by increasing total caloric intake or drive consumers towards unhealthy ultra-processed foods.
Celsus might approve of knowledge that improves recognition and sharpens questions. But he would be wary of knowledge that encourages overreach or a false sense of mastery.
Ancient Principles for Informed Medicine
If we put Celsus into conversation with the present, a few principles emerge. These are less rules than sensibilities that Celsus seeks to model in his own work, useful perhaps not only for his Roman audience but also for the health-optimizing informed patient of today.
§ Weighing the causes. Celsus is not satisfied with an account of the mechanism alone and recognizes that one-off outcomes are not always trustworthy: sound judgment lives in the undogmatic interplay of reason and experience, tailored for each person’s unique situation.
§ Appreciating and managing risk. Celsus begins with low-risk, high-value interventions, such as diet, exercise, and lifestyle. He cautions against risky interventions and projects a moderate approach tailored to the severity of the case.
§ Respecting thresholds of skill. Medical knowledge is a complex of theory and experience—an art whose difficulty is aptly summed up in the Hippocratic aphorism (1.1), the art is long, life is short. Celsus would be the first to point out that an informed layman is not a physician (medicus). Being an informed patient means knowing what you are not informed about and cannot do yourself.
§ Improving, not scrapping, public conversations. Celsus’ intervention did not scrap the learned Greek medical traditions in favor of homespun remedies such as egg and wool (compare Pliny the Elder’s preference in Natural History, 29.1–28). Rather, he sought to distill the best of it. This collaborative approach to conversation trumps unnuanced rejection and makes the conversation one of shared reasoning, rather than a clash of authorities.
Medicine as a Civic Art? The Culture of the artes
The emergence of these sensibilities is an important but underrated moment in the development of medicine in Greek and Roman antiquity and was driven by the intellectual culture of the Roman artes more broadly. The artes elaborated a form of public-facing scientific engagement, allowing non-experts to learn about the technical knowledge that structured their world and to better understand their own place in both nature and human society. When Celsus wrote about medicine in Latin as a part of his larger Artes, he wrote precisely this audience. By placing regimen in the foreground, narrating sectarian debates as live questions, and repeatedly marking the boundaries of risk, he projected a moderate, pragmatic conception of medicine ideally tailored to civic consumption. That is, he brought medicine into a common space of reasoning and conversation that stands to make his audience better at engaging with this indispensable art.
Celsus’ ambition seems highly relevant today. The democratization of expertise, the popularity of proactive longevity medicine, and the movement towards becoming informed patients are straining not only the medical establishment but also public discourse and politics. On one side is the Scylla of the collapse of trust in the medical establishment, on the other the Charybdis of apathy towards the everyday decisions that are driving, for example, a still-worsening obesity crisis. Yet contemporary trends also present an opportunity. Celsus’ medical writings can help us chart a course between these extremes: learn enough to live wisely and ask well; know where the thresholds of expertise begin; and make knowledge an instrument of trust rather than of sowing suspicion.
Works cited
Topol, Eric. 2025. Super Agers: An Evidence-Based Approach to Longevity. New York: Simon & Schuster.
Zainaldin, James L. 2025. The artes and the Emergence of a Scientific Cultlure in the Early Roman Empire. Cambridge: Cambridge University Press.
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