Medical History: The Black Death

The bubonic plague left an indelible stamp on 14th-century European clinical practice. We take a look at this tragic chapter of human history from a medical angle.

Translated from the original Italian version.

The plague

The plague is an infectious disease caused by the Gram-negative bacterium Yersinia pestis, discovered by Alexandre Yersin in 1894, at the same time as ShibasaburĊ Kitasato, during an epidemic in Hong Kong. Symptoms are those of severe pneumonia (pneumonic plague) or a voluminous and painful lymphadenopathy with high fever, often progressing to septicaemia (septicemic or bubonic plague). The diagnosis is epidemiological and clinical, confirmed by culture and serological tests. Treatment involves streptomycin or gentamicin; while alternatives include fluoroquinolone or doxycycline.

The plague occurs mainly in wild rodents, and is transmitted from rodent to human through the bite of a vector such as an infected flea. Plague can also be spread through contact with the fluid or tissue of an infected animal. Interhuman transmission occurs through the inhalation of droplets from patients with lung infection (primary pneumonic plague), which is highly contagious.

There is currently no vaccine available against plague, so no preventive treatment of this disease is possible. It is therefore essential to recognise the symptoms quickly and intervene within the first few hours of their appearance. Plague is widespread in all places where homes are infested with fleas and rats, and therefore in conditions of poor hygiene.

The last urban outbreak of plague in the United States was in 1924-25, in Los Angeles, and since then the disease has been occurring mainly in rural areas at the rate of 10-15 cases per year. Globally, WHO reports 1,000 to 3,000 cases of plague each year, distributed mainly between Africa, Asia and South America. In Asia, plague is widespread in the Caucasus, Russia, the Middle East, China, and also in parts of Southwest and Southeast Asia.

25 million dead

The Black Death was an epidemic that hit Europe particularly hard, spreading also to Asia and North Africa. Cities, with their high population density and poor hygiene, were the worst affected. In the early Middle Ages, urban centres were nothing more than a maze of streets, wooden hovels and mud; all bathed in filth, making them the ideal environment for rats. The pandemic in Europe unfolded from 1347 to 1350, and is estimated to have killed 25 million people, one third of the European population at the time. In some specific areas, mortality rates were much higher. This unprecedented demographic loss had profound repercussions on medieval society, creating gaps in the labour force, destabilising communities, and affecting social structures.

The term 'plague' (from the Latin pestis, meaning 'destruction, ruin, epidemic') indicated in the Middle Ages many diseases characterised by high mortality and spread, such as cholera, measles or smallpox.  The expression 'black plague' refers specifically to the plague epidemic of the 14th century, because symptoms included the appearance of dark, livid spots of haemorrhagic origin on the skin and mucous membranes of the sick. This epidemic of the mid 14th century is also known by the epithet Black Death.

Origin of the Black Death

The Black Death of the 14th century originated in Caffa (Crimean peninsula) during a Mongol siege; spreading rapidly through trade routes, affecting the Mediterranean basin and later all of Europe. It is speculated that this event marked the first biological war in history, with the Mongols spreading the disease by catapulting infected corpses over the city walls. The Genoese merchants, fleeing in terror, carried the contagion to Constantinople and Italy, from where it spread further. In addition to trade routes, pilgrimages also contributed to the spread of the disease, connecting individuals from different regions. From the affected areas, the plague spread to surrounding villages, towns and countryside.

FlappiefhCC BY-SA 4.0, via Wikimedia Commons

Clinical and distinctive signs

The Black Death presented various clinical manifestations, with the bubonic form being the most common. Inflamed lymph nodes, buboes, were often the first sign of the disease. They appeared in the groin, under the armpits or on the neck, representing the most obvious manifestation of the disease. Symptoms for sufferers included high fever, chills, spasms and delirium.

The septicemic form and the pulmonary form, the latter being highly contagious, represented variants of the disease with distinctive symptoms and complications. The pneumonic plague attacked the respiratory system, causing a cough full of pestiferous bacilli and allowing contagion from person to person through the air. In the case of septicemic plague, often a consequence of the bubonic form, the infection spread through the bloodstream, manifesting as dark spots on the skin, hence the name 'black death' given to the epidemic. The pulmonary plague and the septicemic plague were the deadliest.

In 1365, Guy de Chauliac, personal physician to three popes and the king of France, distinguished pneumonic plague from bubonic plague in a purely empirical way, without obviously investigating its causes. In Guy's Chirurgia Magna we read:

"The illness lasted [in Avignon, ed.] seven months. There were two forms. The first lasted two months and was characterised by persistent fever and haemoptysis, with death occurring within three days. The second lasted a long time, also with persistent fever and was characterised by the formation of pustules and boils on the skin, especially in the axillary and inguinal regions. He died after five days'.

Guy de Chauliac, Chirurgia Magna

Of course, in both cases, the disease had a variable duration. There were also some who survived the bubonic plague. In those who survived, a relative immunity was described as early as the 14th century.

Diagnosis and classification

The diagnosis of the Black Death was based primarily on the observation of characteristic symptoms. Doctors of the time developed classifications based on the severity of the disease, attempting to distinguish between mild, moderate and severe forms. This stratification was crucial for adopting a customised therapeutic approach and planning specific interventions.

Death strangles a plague victim. From the Stiny Codex, 14th century. Artist : Anonymous. University Library, Prague

How was the Black Death treated?

Medieval medical practice was based on traditions inherited from antiquity, and treatments for the Black Death reflected these influences. The use of medicinal herbs, potions and amulets was common, but the effectiveness of such remedies was often limited. The lack of an accurate understanding of the disease's causes made it difficult for doctors to provide effective treatments.

In general, medieval physicians relied on ancient authorities such as Hippocrates and Galen, who adhered to the humoral pathological theory. According to this theory, diseases were caused by an imbalance of the body's four humours. The prevalence of black, cold, and dry humour was associated with plague.

Putrefaction, caused by the predominance of specific humours, was believed to spread through the body via air or food. The sultry and humid climate and the southern winds were considered dangerous. Exhalations, especially from the breath of those already ill, were feared as highly infectious. Doctors tried to treat the plague through phlebotomy, enemas, purifying smoke, disinfectants such as vinegar, and face and hand washing.

Doctors recommended preventive measures such as isolating the sick, avoiding specific foods, using aromatic substances and fleeing the affected areas. They also recommended behaviours such as laughing, joking and celebrating, emphasising the importance of joy to remain balanced. Medical manuals of the time, such as those known in the formats of "consilia" (advices) and "regimina" (guidelines), provided instructions for dealing with the epidemic. They focused on prevention rather than cure.

In the 'Consilium' of Gentile da Foligno (who died in 1348), it was recommended to light fires in homes. All food was to be soaked in wine. Camphor was to be used as odorous substances in the case of hot meals and selaginella (also known as spikemoss) in the case of cold meals. Acidic foods were considered the optimal food. Gentile da Foligno's 'pestiferous breath' theory stated that corrupted winds carried harmful substances into the air. Starting with Gentile, the basic therapies against plague were theriac1 use, as well as bloodletting and isolation of the sick.

In the 'Council Against Pestilence'2 by Tommaso del Garbo (1305-1370), for example, bread dipped in wine was recommended as a defence against contagion. Cloves were also suggested, whose perfume would have a disinfectant effect. Advice was also given for priests, who had to take confession from the dying: everyone was to move away from the sick person's room, so that the sick person could raise his voice and confess his sins to the priest, who could then stand at a distance.

Another piece of advice against the plague written by Giovanni Dondi (1330-1388) recommended avoiding fog and mist, as well as the dreaded southerly wind. Moreover, a morning exposure to the fumes of a fire made by burning scented wood, such as olive, oak, ash, sandalwood and myrtle was recommended. Washing hands with rosewater and vinegar was essential. Dondi advocated bloodletting, also to be practised on the heads of the sick, in order to reduce the 'infected' blood from the body.

In his 'Regimen tempore pestilentiae', Siegmund Albich (1347-1427), personal physician to King Wenceslas of Bohemia and professor at the University of Prague, exhorted 'not to speak or think about the plague because even just the fear of the epidemic, imagining it and talking about it are undoubtedly the cause in man of the onset of the disease itself'.

Isolation and quarantine

Despite the lack of understanding of the microscopic causes of the disease, medieval physicians sought empirical approaches based on humoral concepts and preventive measures, demonstrating a primitive understanding of the isolation of sick individuals as an effective method to counter the spread of plague.

Given the highly contagious characteristics of the plague, isolating patients and implementing quarantine measures were common practices. These measures were often rudimentary, however. During the pandemic, the authorities introduced potentially effective preventive measures, such as isolating the infected, reducing human contact and travel, cleaning public places and establishing health offices. The experience of the pandemic helped to refine the preventive measures, and subsequent plague outbreaks were limited to one or a few cities, without achieving the same spread as the 'black death'.

Divine retribution and the persecution of the Jews

The plague was seen as God's punishment for the sins of men. This idea rekindled a strong religious fervour, which led to the revival of the penitential movement in the south of France and in northern and central Europe, thus giving rise to the so-called 'processions of the flagellants'. The scarce medical knowledge did not allow the disease to be defeated. A sense of frustration and helplessness thus spread throughout Europe. It was thought that if those responsible for the epidemic were found, God's wrath would be appeased.

The blame was thus placed on minorities, the poorest and weakest, with beggars, vagrants, and Jews becoming scapegoats. A tragic phenomenon unfolding during and after the Black Death was the increasing persecution of Jews in many European communities. Wrongly accused of poisoning wells and spreading disease, Jews were often subjected to violence and massacres. These events underline the connection between health crises and the spread of irrational prejudices and conspiracies, highlighting the complex social and cultural role of medicine in the medieval context.

The plague in Europe after 1300

The plague persisted in Europe for another two hundred years after 1351, but in the period up to the 17th century it mainly struck in mild forms, without affecting the entire continent.

Between 1629 and 1679, further epidemics struck Europe. In 1629, the plague was introduced into northern Italy by the Landsknechts, leading to riots and famine. The spread in 1630 caused economic damage and social changes, with control measures such as bans on feasts and travel, controls at city gates, and punishments for intentional disease spreaders.

Medical conditions in the 17th century were described in detail by Alessandro Manzoni's The Betrothed (Original title: I Promessi Sposi), which recounted the spread of the plague in Milan. Subsequent epidemics struck Naples and Rome in 1656, while in 1665 and 1679 they spread to London and Vienna.

The 18th century saw socio-economic and sanitary improvements, contributing to the decline of the plague in Europe by the arrival of the 19th century.

  1. Theriac was a medical concoction dating back to the 1st century AD. For more information we recommend: Demetrios Karaberopoulos, Marianna Karamanou, George Androutsos. The theriac in antiquity. The Lancet, PERSPECTIVES|THE ART OF MEDICINE| VOLUME 379, ISSUE 9830, P1942-1943, MAY 26, 2012. DOI:
  2. Consiglio contro a pistolenza, Tommaso del Garbo. Mentioned in Post-Decameron Plague Treatises and the Boccaccian Innovation of Narrative Prophylaxis Martin Marafioti Annali d'Italianistica Vol. 23, Literature & Science (2005), pp. 69-87 (19 pages) Published By: Annali d'italianistica.