Writing about the first outbreak of the English Sweating Sickness of 1485 in London, French physician Thomas Le Forestier provided a gripping eyewitness account that encapsulated the terror it sowed. “We saw two priests standing and speaking together, and we saw both of them die suddenly. Also we saw the wife of a tailor taken and suddenly died. Another young man walking by the street fell down suddenly.”


Le Forestier communicated the randomness of epidemic illness: men and women, not only the merchant classes but also the clergy, were vulnerable. Although, as a learned doctor, he had considerable medical expertise, he was powerless to help these people affected by an acute, unknown and deadly fever.

It’s no coincidence that Le Forestier defined this illness in terms of sudden death. If a person died unexpectedly, they had not had a chance to confess their sins to a priest, and thus the fate of their soul was in danger. Concerns about the soul were closely bound up with anxieties about bodily health in the Middle Ages.

It was sometimes held that illness was inflicted by God as a result of sin. Furthermore, the Church taught that in order to recover from physical sickness, one’s soul needed to be in good health. And the soul was all important – it would endure beyond death, whereas the body was but a temporary vessel.

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Medieval Christians needed to prioritise the wellbeing of their souls, to decrease their time in purgatory (a place where souls were believed to satisfy past sins and be made ready for heaven) and ensure they were saved at the Last Judgement. Religion featured prominently in efforts to protect health and recover from sickness. People appealed to saints for assistance, most notably Thomas Becket, whose shrine at Canterbury was visited from the 1170s by numerous sick pilgrims seeking a miraculous cure.

Painting of a medieval apothecary shop of the 15th century
Apothecaries were the 15th-century equivalent of pharmacists (Photo by Alamy)

Religious beliefs were also sometimes combined with magical ideas and practices. Prayers and the names of saints were written on pieces of paper or parchment that could be worn on the body to ward off illness and misfortune. The idea was that the written words had a magical potency to dispel the influence of the devil and demons. Although magic was problematic for the church, prominent religious figures still engaged in these practices. The famous healer Saint Hildegard of Bingen (1098–1179) once wrote a letter to a woman, Sibylla, to staunch her bleeding. Hildegard vehemently instructed: “O blood, restrain your flow.” Sibylla was advised to place the letter on her body, no doubt so that the words’ power could heal her.

The four humours and the role of astrology in medicine

Celestial influences on the human body encompassed not only the will of God and the saints, but also the movements of the planets, especially the Moon. It was held that each of the 12 signs of the Zodiac was associated with a particular part of the body – Pisces governed the feet, Aries governed the head, and so on. When the Moon moved into a Zodiacal sign, blood was thought to pool in that part of the body, making it dangerous to perform bloodletting and other medical procedures there.

It was understood that if a person had too much or too little of any of the four humours – blood, phlegm, yellow bile and black bile – they would become ill

Although these astrological ideas were very widespread, encapsulated in handy diagrams such as the Zodiac Man image, not all doctors subscribed to them. Writing between 1432 and 1453, French physician Jacques Despars lamented that: “The judgements of astrology are for the most part uncertain, unstable, ambiguous and often deceptive”. He advised that in urgent cases bloodletting should take place immediately, regardless of the positioning of the planets.

Bloodletting was so essential because it maintained the balance of the humours, the four fluids believed to be present inside the body. It was understood that if a person had too much or too little of any of the four – blood, phlegm, yellow bile and black bile – they would become ill.

Medieval people also believed that environmental factors and behaviour had an impact on health, in terms of the quality of the air, diet, sleep and exercise. Emotional states, known as ‘accidents of the soul’, were another factor. These ideas were inherited from the Ancient Greek author Galen, whose writings were translated into Arabic and then Latin.

What was the worst medieval disease?

Was the Sweating Sickness more likely to be fatal than the bubonic plague? Is dysentry more or less painful than leprosy? Think of this as top of the pox, but where the pox is only one of your worries...


While modern-day medicine can defeat many infections with antibiotics, no such treatments existed in the Middle Ages. People were aware that wounds, childbirth and surgery were all dangerous moments because of the risks of infection. Although they did not have our understanding of how infections take hold, medieval people knew exactly what they were, sometimes describing them as fevers.

First appeared/recorded: Pre-history

Incubation period: 1-10 days (for puerperal fever after childbirth)

Risk to life: 9/10

The Pox

Although the pox only affected Europeans in the 1490s, it immediately caused great anxiety and fear. This sexually transmitted disease, roughly equivalent to modern-day syphilis, caused pain and unsightly swellings, and could attack the nose and the face. Contemporaries linked it to prostitutes and immoral behaviour.

First appeared/recorded: c3000 BC

Incubation period: 21 days (average)

Risk to life: 8/10


After the plague, leprosy is the disease most synonymous with the Middle Ages. It was certainly a major issue for contemporaries, judging by its prominence in medieval literature, art, documents and saints’ lives. Comparatively few people actually developed leprosy, since it isn’t heavily contagious, but those who did get it suffered skin sores, facial disfigurement and sometimes blindness.

First appeared/recorded: 1550 BC

Incubation period: 5 years (average)

Risk to life: 2/10


In late medieval England, outbreaks of an epidemic illness known as ‘the bloody flux’ or ‘dysentery’ were reported. This intestinal infection, causing blood-filled diarrhoea, manifested especially in crowded, dirty conditions. Though thoroughly unpleasant and deadly, it was much less frequent than plague epidemics.

First appeared/recorded: 2nd-5th centuries AD

Incubation period: 1-4 days (average)

Risk to life: 8/10

Bubonic plague

The most intensely feared killer in medieval Europe was pestilential illness. The Black Death of 1347–51 was unprecedented, and decimated more than half the population in certain areas. Following another epidemic in the 1360s, there were recurrent plague outbreaks in England, France, Italy and elsewhere well into the 17th century.

First appeared/recorded: AD 541-750

Incubation period: 2-6 days (average)

Risk to life: 10/10

The Sweating Sickness

This disease was almost exclusively confined to England. After the first outbreak in 1485, four more epidemics occurred up to 1551. Sufferers experienced great thirst, heavy sweating and a high fever; they usually died within about five hours. The English Sweat seemed to affect the more affluent sectors of society, with young men especially vulnerable.

First appeared/recorded: 1485

Incubation period: Unknown

Risk to life: 9/10

Since many illnesses were potentially deadly, the best approach was prevention: staying healthy through a balanced lifestyle. When sickness did occur, attention to food and drink, exercise and other kinds of activity, as well as one’s emotions, could bring about recovery. A 15th-century English medical text advised that a man who was spitting blood should “beware of anger, and being with women, … and sour foods, and salty ones, and sharp ones, and of hard work, and of much thinking”.

Ideas about the air were fundamental to thinking about how disease was spread. It was understood that illnesses entered the body when corrupt or poisoned air was inhaled into the lungs or transmitted through pores in the skin. This polluted air, known as miasma, was foul smelling, but could be counteracted through sweet smells such as rose scent or sandalwood. Although these ideas existed before the Black Death struck Europe in the late 1340s, this devastating plague epidemic and subsequent outbreaks caused great anxiety about noxious air. Town governments across Europe enacted public health measures against malodorous waste: in 1357, for example, the mayor and aldermen of London threatened to fine or imprison anyone who deposited animal dung or other smelly waste in the city streets.

The Black Death

The worst plague outbreak of them all was blamed on an inauspicious planetary alignment

The plague outbreak that suddenly afflicted Europe from 1347–51 was terrifying: it killed up to 60 per cent of the population, and doctors were powerless to treat it.

This illness appeared in two main forms: pneumonic plague, which affected the lungs and made the sufferer cough up blood, and bubonic plague, which caused swellings (buboes) on the body, especially in the groin and armpits.

Modern-day scientists have identified the cause as the bacterium Yersinia pestis, carried by wild rodents. The bubonic form was transmitted to humans via fleas, but the pneumonic form, the most lethal strain, was transferred from person to person through the air.

Contemporaries clearly recognised the forms and symptoms of the plague. The French physician and surgeon Guy de Chauliac witnessed the epidemic in Avignon in 1348, to where it had spread rapidly from Italy. He noted that the pneumonic form was especially contagious, writing that one man “caught it from another not just when living nearby but simply by looking at him”.

De Chauliac was one of the few to recover from bubonic plague, after falling into a gravely dangerous fever. Like the physicians of the University of Paris, who reported on the plague in October 1348, he identified the primary cause as a conjunction of planets in the sign of Aquarius in 1345. This signified a great mortality, and caused the air to become corrupted.

Thanks to microbiologists, we are still learning more about the Black Death and the subsequent plague outbreaks that affected Europe from the 1360s right up to the 1720s, and the presence of the bacterium in other parts of the world up to the present day. Ancient DNA analysis has reconstructed the genome of Yersinia pestis from medieval skeletons, enabling exploration of the reach and mutation of the illness over time and space.

Were there doctors in medieval times?

Who could one turn to for expert help when sick in the Middle Ages? Physicians, whose services were often expensive, would diagnose illnesses by examining a patient’s urine and pulse, and then offer advice based on the humours and lifestyle factors. Some doctors, like Taddeo Alderotti (d1295) who taught at the University of Bologna, produced advice letters for specific patients that then circulated for more general use.

Unlike doctors, surgeons and barber-surgeons intervened manually, applying ointments and dressings, performing bloodletting, and occasionally cutting into the body for more complex surgical procedures. Medieval skeletons excavated by archaeologists – such as a male skeleton from the leprosy hospital at Winchester with an amputated left leg – sometimes indicate that major surgery took place, and that patients at least initially survived the experience.

Most of these practitioners were men, but women also gained medical expertise. In the later Middle Ages, nuns from the Franciscan monastery of Longchamp (west of Paris) are known to have practised as barber-surgeons. Women also played a vital role as midwives, with male physicians and surgeons usually only involved in complex, difficult deliveries of infants, such as posthumous Casearean sections.

Medicines themselves were formulated and dispensed by apothecaries, who were the pharmacists of their day. Like physicians, these tradespeople could become very wealthy, charging high prices for their remedies. At the upper end of the apothecaries’ trade, they marketed drugs with exotic ingredients from far-flung places, such as opium from Thebes and alum (a metallic substance) from Sardinia or Egypt. In the 1370s, the great hospital of Santa Maria Nuova in Florence was spending more than £1,000 per year on medicines, a considerable sum.

The remedies, mostly made of natural ingredients such as aniseed and rose petals, were supplied by the apothecary Ugolino di Bonsi and distributed from the hospital’s on-site pharmacy. A less reputable figure than di Bonsi was the London apothecary John Hexham, hanged in 1415 for counterfeiting money. The inventory of Hexham’s possessions mentions a still, an essential piece of equipment for distilling liquids to produce medicines. Some larger households in the later Middle Ages possessed stills, showing that people could adopt a ‘do it yourself’ approach and make their own medical remedies at home.

Medicines of the medieval era

Aspirin and paracetomol are nowhere in sight in the medieval medicine cabinet; innards, on the other hand...


To treat gout. One should: “Take an owl and pluck it clean and open it, clean and salt it. Put it in a new pot and cover it with a stone and put it in an oven and let it stand till it be burnt. And then stamp [pound] it with boar’s grease and anoint the gout therewith.”


In lieu of a bag of frozen peas, snail slime was often rubbed on burns and scalds.


This poisonous plant boasted powerful laxative effects.


The most exotic and sought-after of medieval drugs, theriac contained more than 70 ingredients, including vipers’ flesh. It was believed to be a powerful antidote to poisons, as well as to possess other healing properties.

St Paul's Potion

One proposed cure for epilepsy, catalepsy and stomach problems was St Paul’s Potion, a concoction containing (among other things) liquorice, sage, willow, roses, fennel, cinnamon, ginger, cloves, cormorant blood, mandrake, dragon’s blood and three kinds of pepper.

Dried toad

The bumpy skin and often poisonous nature of the toad meant it was often seen as an antidote to plague; dried specimens would be laid on plague buboes.


Used to draw out ‘bad blood’ – the perceived cause of many medieval illnesses – from a patient.

Onion or leek

A trusted treatment for styes. Cropleek – which may be equivalent to modern onion or leek; there’s still debate – was mixed with bull’s gall and wine, stood in a brass bowl for nine nights, then strained. The final step was application: at night-time, using a feather.

Horse saliva

A recommended cure for women suffering from a perceived lack of libido.


An essential ingredient of numerous medieval medical remedies, honey was used to sweeten unpleasant-tasting medicines, but also for its own healing properties.


Spiderwebs were sometimes used to dress wounds. Their stickiness could help hold a cut together, while their natural antiseptic and antifungal properties would combat infection.


A herb plant and part of the mint family, horehound was often used to treat coughs.

Hospitals were not the primary site for the attentions of medical practitioners and the availability of their remedies in the medieval period. Hospitals were really a last resort, as they were charitable institutions that helped the sick poor who could not afford to receive treatment at home. They often followed a monastic rule, and attracted donations from Christians keen to fulfil good works to benefit their own souls. Some of the larger hospitals in cities like Paris, Nuremberg, Rome and London catered for large numbers of short-stay patients. By the first years of the 16th century, Santa Maria Nuova in Florence received a staggering 6,500 patients per year, accounting for almost 10 per cent of the urban population of 70,000.

What were medieval hospitals like?

Other hospitals were much smaller, including specialised institutions for abandoned children, the blind, those afflicted by Saint Anthony’s Fire (a disease caused by eating rye bread infected with the ergot fungus, resulting in pain, gangrene and mental confusion) and leprosy sufferers. The leprosy hospitals offered long-term care, since in the Middle Ages there was no cure for this disfiguring, debilitating disease. Because leprosy could progress slowly, some patients were well enough to play an active role in community life.

Fourteenth-century regulations for the Enköping leprosy hospital in Sweden instructed that those “who are strong enough and able to work ought to help ... to bring in the hay and to harvest the grain”. Other leprosy hospital regulations emphasised the need for men and women to live separately, since chastity was essential in these monastic or quasi-monastic institutions. Rules for the hospital at Meaux, northeast of Paris, stated that if a leprous man was found at night with a woman he would be put on a diet of bread and water.

Scene of patients being treated in a medieval hospital
Hospitals were not considered a first port of call for expert medical care in the medieval era – in fact they were more of a large resort (Photo by AKG Images)

Although leprosy hospitals were located outside towns and cities, they remained in contact with local populations and, contrary to modern-day stereotypes, there’s little evidence that people with leprosy were excluded or stigmatised. On the contrary, the charity that supported these institutions marked the patients’ continuing inclusion in the Christian community. Jewish and Muslim populations in Europe also supported the sick within their communities. At Provins in northern France, a Jewish leprosy hospital is documented in the 13th century.

While being alive in the Middle Ages meant vulnerability to acute and chronic illnesses that modern medicine can now treat, and often having very little access to doctors and surgeons, the overriding impression is that medieval people were physically and mentally resilient and highly knowledgeable about their own health. Much medical expertise and support was provided within the local community, or was available at nearby monastic houses.

The mentally ill, for example, usually remained at home, with one of the earliest specialised mental hospitals, Saint Mary of Bethlehem in London, only active from the later 14th century. Medieval people used natural, magical and celestial resources to protect their health, and faced illness and disease with determination, pragmatism and religious faith.

Medicine in the medieval monastery

Religious worship may have been the mainstay, but medical expertise was a happy side effect

Although we may think of monasteries as centres of religious devotion, they were incredibly important sites of medical care in the Middle Ages. As was the case in lay society, the focus was on staying healthy, with bloodletting, to keep the bodily humours in balance, integrated into the monastic calendar. Most monasteries had their own infirmary, a sick ward where monks and nuns who became unwell could rest and receive treatment.

The sick were soothed with remedies containing medicinal plants grown in the monastery’s herb gardens. Most therapeutic expertise was available in-house, since monks and nuns acquired extensive medical knowledge through reading learned medical books, as well as through practical experience.

While most surviving medical manuscripts from monasteries come from large communities like the abbey of Bury Saint Edmunds, medicine was important at smaller houses too. A tiny Benedictine priory at West Mersea in Essex possessed a heavily used book with texts on urines and pulses, alongside medical notes and recipes.

Monasteries were an ideal setting for religious women, most famously Hildegard of Bingen, who founded her own nunnery at Rupertsberg in Germany, to develop medical expertise. Some communities also offered care to sick or disabled lay people who were not monks or nuns.

At the nunnery of Bondeville in Normandy, France, for example, women with mental impairments were among residents in the 13th century.

Dr Elma Brenner is Wellcome Collection’s medieval specialist


This content first appeared in the March 2020 edition of BBC History Revealed