Physicians in 1348 fought the Black Death with an arsenal that ranged from ancient compound medicines and bloodletting to burning aromatic herbs and lancing the swollen lymph nodes (buboes) that gave bubonic plague its name. None of these treatments could stop the bacterium responsible, because germ theory would not exist for another five centuries. But the remedies were not random guesses; they followed a coherent medical logic rooted in humoral theory and the conviction that corrupt air caused disease.
The Medical Theory That Shaped Every Treatment
To understand why 1348 physicians prescribed what they did, you need to know the lens they were looking through. Virtually all university-trained doctors in Europe and the Islamic world operated within a framework inherited from Galen, the second-century Greek physician, and refined by the Persian scholar Ibn Sina (Avicenna). Health depended on the balance of four bodily humors: blood, phlegm, yellow bile, and black bile. Disease arose when something knocked those humors out of alignment.
The dominant explanation for plague specifically was miasma, the idea that poisonous or “corrupt” air entered the body and disrupted the humors. Treatises on plague in both the Christian and Islamic worlds tried to explain the disease within this Galenic-Avicennian framework, drawing their basis from miasma theory and shaping the language and content of medical advice at every level.1Nazariyat İslam Felsefe ve Bilim Tarihi Araştırmaları Dergisi. Silent Sources of the History of Epidemics in the Islamic World: Literature on Ṭāʿūn/Plague Treatises This was not ignorance dressed up as science. It was the best theoretical model available, and physicians applied it with genuine rigor. They were simply working from premises that turned out to be wrong.
Because the cause was believed to be bad air, treatments fell into a few broad categories: purging the body of corrupted humors, strengthening the body against further corruption, and cleansing or masking the air itself. Nearly every remedy prescribed in 1348 fits one of those three goals.
Theriac, the Universal Antidote
If one medicine stood above all others in the plague physician’s toolkit, it was theriac (also called treacle). Theriac was an ancient compound remedy that had been in continuous use since Roman times, originally developed as an antidote to poison and venomous bites. By the fourteenth century, it had become the go-to treatment for pestilence. A typical theriac recipe contained dozens of ingredients, sometimes more than sixty, including opium, viper flesh, myrrh, cinnamon, and various botanicals, all mixed into a thick paste and aged for years before use.
The consistent use of theriac in plague medicine reflected more than blind tradition. Scholars who have examined the pharmacological properties of its ingredients argue that the rationale combined humoral doctrine, empirical observation, and genuine pharmacological effect.2PubMed. Treating medieval plague: the wonderful virtues of theriac Opium would have dulled pain and reduced the agony of swollen buboes. Several botanical ingredients had mild antiseptic or anti-inflammatory properties. Theriac could not cure plague, but it likely provided real symptomatic relief, which in a world without effective antibiotics was not nothing.
Physicians typically prescribed theriac dissolved in wine or vinegar, sometimes applied directly to the buboes as a poultice. The medicine was expensive, and high-quality aged theriac was a luxury item. Poorer patients often received cheaper imitations or simplified versions with fewer ingredients. The gap between what a wealthy merchant could access and what a peasant received was enormous, a pattern that repeated across every type of plague treatment.
Bloodletting, Lancing, and Purging
Bloodletting was one of the most common medical interventions of the medieval period, used for everything from fevers to headaches, and plague was no exception. The logic was straightforward within humoral theory: if corrupt humors were circulating in the blood, removing some of that blood should help restore balance. Physicians bled patients from specific veins depending on which part of the body was affected. A bubo in the groin might call for bleeding from a vein in the leg; a bubo in the armpit might mean opening a vein in the arm on the same side.
Lancing the buboes themselves was a separate and more aggressive procedure. The swollen lymph nodes characteristic of bubonic plague could grow to the size of an egg or larger, and they were excruciatingly painful. Surgeons would cut them open to drain the pus and fluid, sometimes applying hot poultices or caustic substances to draw the corruption out. This was agonizing for the patient, and there is some evidence from later plague outbreaks that draining a bubo before it burst on its own occasionally improved survival, though the reasons had nothing to do with humoral theory.
Purging rounded out the triad. Physicians prescribed emetics to induce vomiting and laxatives to empty the bowels, both aimed at expelling corrupt humors from the body as quickly as possible. Some recommended enemas. The combined effect of bloodletting, lancing, and purging on a patient already weakened by plague was often devastating, hastening death rather than preventing it. But the internal logic was consistent: if the body is full of poison, get the poison out by any available exit.
Smell as Medicine
Because physicians believed plague spread through corrupted air, an enormous portion of the medical advice from 1348 centered on what people should breathe. The recommendations ranged from practical fumigation to what now seems almost comically naïve, but all followed from miasma theory.
At the household level, people burned aromatic woods and herbs indoors. Juniper, rosemary, pine, and laurel were popular choices. Wealthy households burned frankincense and myrrh. Vinegar was splashed on floors and walls and heated in pans to fill rooms with its sharp vapour. The idea was that strong, pleasant smells could neutralize or overpower the poisonous miasma. Physicians carried pomanders, small balls of aromatic compounds, and held them to their noses when visiting patients. Ordinary people carried bunches of herbs or flowers for the same purpose.
Some advice went further. The medical faculty of the University of Paris, which issued one of the most influential plague treatises of 1348, recommended avoiding bathing, on the theory that open pores allowed corrupt air to enter the body more easily. This guidance persisted for generations and contributed to a broader European retreat from regular bathing that lasted well into the early modern period. It made sense if you believed disease was an airborne poison that seeped through the skin, but it likely worsened sanitation and helped other diseases spread.
Fires were lit in public streets and squares in some cities, on the theory that large flames could purify the surrounding air. Gunpowder was occasionally discharged for the same purpose. While none of this killed the plague bacterium or the fleas that carried it, the widespread use of fire and smoke may have had one accidental benefit: smoke can repel some insects, and it is possible that heavy fumigation in enclosed spaces drove away a few flea vectors, though this would have been far too inconsistent to make a meaningful difference.
Religious and Supernatural Responses
For most people in 1348, medicine and religion were not separate categories. Prayer, pilgrimage, and appeals to saints were as much a part of the response to plague as any herbal remedy. The Church taught that epidemic disease was divine punishment for collective sin, and much of the population accepted this framework alongside, or even above, the physicians’ humoral explanations.
Processions wound through city streets with participants chanting, praying, and carrying relics. Masses were said for the dead and for deliverance from the pestilence. Special prayers to St. Sebastian and St. Roch, both associated with plague protection, became widespread. The flagellant movement, in which groups of laypeople traveled from town to town publicly whipping themselves to atone for humanity’s sins, surged during 1348 and 1349. The movement grew large enough that Pope Clement VI eventually condemned it, partly because the flagellants had begun bypassing Church authority and partly because their mass gatherings almost certainly helped spread the disease.
Amulets and charms occupied a space between religion and what physicians would have considered folk magic. People wore inscribed stones, carried written prayers, or placed blessed objects in their homes. Plague treatises from the Islamic world acknowledged this dimension as well: the encounter with such a devastating illness prompted a quest for all possible remedies, including occultist culture.1Nazariyat İslam Felsefe ve Bilim Tarihi Araştırmaları Dergisi. Silent Sources of the History of Epidemics in the Islamic World: Literature on Ṭāʿūn/Plague Treatises When conventional medicine failed so visibly, it is unsurprising that people turned to anything that promised protection.
Dietary and Lifestyle Advice
Medieval physicians took diet seriously as medicine, and plague treatises devoted considerable space to what patients and healthy people should eat and avoid. The general principle was to consume foods that were “warm and dry” in humoral terms, because plague was thought to be caused by “warm and moist” corruption. This meant favoring roasted meats over boiled, eating bread made from wheat rather than rye, and seasoning food liberally with pepper, ginger, and other spices believed to have drying properties.
Certain foods were specifically warned against. Fruit was considered dangerous because of its moist, easily corrupted nature. Fish, particularly freshwater fish, was suspect. Dairy products were discouraged. Wine, on the other hand, was widely recommended, sometimes mixed with spices or herbs, on the grounds that it warmed the body and resisted putrefaction. Vinegar was endorsed both as a drink and as a disinfectant, and it was one of the few medieval remedies that had any genuine antiseptic value, though not enough to matter against Yersinia pestis.
Beyond diet, physicians offered behavioral advice. Avoid exertion and strong emotion, because both were thought to open the pores and make the body vulnerable. Sleep on your right side. Keep rooms cool in summer and warm in winter, but ventilated. Avoid the south wind, which was considered the most pestilential. Some treatises recommended sexual abstinence on similar grounds: any activity that heated the body and opened the pores was risky. Others, paradoxically, suggested that moderate sexual activity helped expel corrupt humors. The contradictions among competing plague treatises were frequent and left ordinary people without clear guidance.
Flight as the Most Effective Strategy
The single most effective response to plague in 1348 was also the simplest: leave. The Latin phrase “cito, longe, tarde” (flee quickly, go far, return slowly) became the unofficial motto of plague survival, and it was endorsed by physicians as well as common sense. Those who had the means to flee plague-stricken cities for the countryside often survived, not because rural air was somehow purer, but because they removed themselves from the dense human-and-rat populations where the disease spread most efficiently.
Boccaccio’s Decameron, written shortly after the 1348 outbreak in Florence, is framed around a group of wealthy young people who flee the city for a country villa and pass the time telling stories. That framing reflects reality: the rich left, and the poor stayed behind to die. Mortality was not evenly distributed. Cities with dense housing, shared wells, and large rat populations were devastated. Rural areas, while not spared, often experienced lower death rates simply due to lower population density and less contact between households.
Formal quarantine measures did not emerge until later outbreaks. The word “quarantine” itself comes from the Italian “quaranta giorni,” the forty-day isolation period first imposed by the city of Ragusa (modern Dubrovnik) in 1377, nearly thirty years after the initial Black Death. In 1348, the response was less organized. Some cities closed their gates to travelers from affected regions, but enforcement was sporadic and often too late. The disease moved faster than news of it, arriving in new cities before authorities knew to act.
How Islamic Physicians Approached the Plague
The Black Death struck the Islamic world just as hard as Christian Europe. Egypt, Syria, North Africa, and the Arabian Peninsula all suffered enormous mortality. Physicians in these regions worked from the same Galenic-Avicennian medical tradition as their European counterparts, and the treatments they prescribed were strikingly similar: theriac, bloodletting, aromatic fumigation, and dietary regulation.
There were some differences in emphasis, however. Islamic medical writers produced a distinct body of plague literature, sometimes categorized under the Arabic term ṭāʿūn. These treatises attempted to diagnose plague and address its various aspects within the existing medical paradigm.1Nazariyat İslam Felsefe ve Bilim Tarihi Araştırmaları Dergisi. Silent Sources of the History of Epidemics in the Islamic World: Literature on Ṭāʿūn/Plague Treatises A notable theological tension existed in the Islamic response that did not have a direct parallel in Christendom: a widely cited hadith (prophetic tradition) instructed Muslims neither to enter nor to flee a plague-stricken land. This created a conflict between the medical advice to flee and the religious duty to remain, and scholars debated it extensively throughout the pandemic.
Another difference was the relatively stronger tradition of hospitals (bimaristans) in the Islamic world. Cities like Cairo and Damascus had established hospital systems that, while utterly overwhelmed by the scale of the Black Death, provided a more organized clinical setting than most European cities could offer. Patients in these hospitals received compound medicines, dietary management, and basic nursing care. Whether this institutional advantage translated into better survival rates is impossible to determine from the surviving records, but it meant that Islamic physicians had more opportunities to observe the course of the disease systematically and record what they saw.
What the Plague Actually Was, and Why Nothing Worked
The Black Death is now understood to have been caused primarily by Yersinia pestis, a bacterium transmitted to humans through the bites of infected fleas, most commonly fleas living on black rats. The disease took three forms: bubonic (infection of the lymph nodes, producing the characteristic buboes), septicemic (infection of the bloodstream), and pneumonic (infection of the lungs, which could spread directly between people through respiratory droplets). The pneumonic form was nearly always fatal. Even the bubonic form killed an estimated 40 to 60 percent of those infected.
No treatment available in 1348 could kill Yersinia pestis. Effective antibiotics did not exist until the twentieth century, and even modern treatment requires prompt administration of drugs like streptomycin or gentamicin. The bacterium was invisible to medieval observers, and the flea vector was entirely unsuspected. Every treatment directed at balancing humors, purifying air, or draining buboes was aimed at the wrong target. The physicians of 1348 were solving the wrong problem with total conviction, and in some cases their interventions, particularly aggressive bloodletting and purging of already-weakened patients, actively reduced survival.
Still, writing off medieval plague treatment as useless superstition misses the point. Theriac’s analgesic ingredients provided real pain relief.2PubMed. Treating medieval plague: the wonderful virtues of theriac Vinegar had genuine antiseptic properties, even if they were irrelevant to Yersinia pestis. The advice to flee affected areas was epidemiologically sound, even though the reasoning behind it was wrong. And the impulse to quarantine travelers, which would formalize within a generation, laid the groundwork for public health practices that remain in use today. The tragedy of 1348 was not that physicians were foolish. It was that the disease they faced was beyond anything their conceptual framework could accommodate.
Scapegoating as a Pseudo-Treatment
One of the darkest responses to the Black Death was the widespread persecution of Jewish communities across Europe. Rumors spread that Jews had caused the plague by poisoning wells, and massacres followed in hundreds of towns and cities, particularly in the German-speaking lands, France, and the Iberian Peninsula. Entire communities were burned alive or expelled. Pope Clement VI issued papal bulls in 1348 attempting to protect Jews, pointing out that they were dying of plague at similar rates and that the disease raged in places where no Jews lived, but the persecutions continued regardless.
This was not medicine, but it functioned psychologically as a kind of treatment: if the plague had a human cause, then eliminating that cause should stop the plague. The same logic drove the persecution of other marginalized groups, including beggars, foreigners, and people with leprosy. When the massacres failed to halt the epidemic, the violence often intensified rather than stopped, following a grim internal logic of its own. The scapegoating of 1348 is a reminder that when a society faces a catastrophic threat it cannot control, the impulse to find someone to blame can become as deadly as the threat itself.