Medieval Potion Kills Modern Superbug


It might sound like a really old wives’ tale, but a 1,000-year-old Anglo-Saxon potion may hold the key to wiping out the modern-day superbug MRSA. (CNN)

Use our microscopic image to get a good look at MRSA.

Teachers, scroll down for a quick list of key resources in our Teachers’ Toolkit.

Watch this terrific video about the AncientBiotics Project!

Discussion Ideas

  • The medieval treatment described in the CNN article is called a salve. What is a salve?
    • A salve is an ointment for treating wounds or infections. Salves are external and topical, meaning they are applied directly to the wound or infected area. (Salves are not taken internally, like a pill or cough syrup.)


In this 1639 image a woman is treating a wound or illness by attaching several leeches to her forearm. (Read about leeches and other bloodsuckers here.) Engraving by Guillaume van den Bossche, courtesy National Library of Medicine

In this 1639 image a woman is treating a wound or illness by attaching several leeches to her forearm. (Read about leeches and other bloodsuckers here.)
Engraving by Guillaume van den Bossche, courtesy National Library of Medicine

  • The medieval text from which the remedy was taken is called Bald’s Leechbook. (Take a look at it here, courtesy the good folks at the British Library.) The author of the book was named Bald, but why was it called a leechbook, and this remedy one of the “best of leechdoms”? Take a look at the image above for some help.
    • April Fool! (Sort of.) It actually doesn’t have anything to do with leeches—at least not directly. According to this fascinating paper, Anglo-Saxon physicians themselves were called “leeches.” (Although that probably had something to do with the bloodletting treatment depicted above—illustrated about 500 years after Bald’s Leechbook was written, and intermittently still practiced today.) A leechbook was a medical textbook, leechdom a treatment or remedy, and leechcraft the practice of medicine.



  • OK, back to the magic potion! Read through the nice CNN article. How did researchers gather ingredients for the leechdom? (Watch the video above or read this New Scientist article for some help.)
    • The most exotic ingredient, cow bile, was probably the easiest to obtain. Cow’s bile salts are a medical staple, sold as a supplement for people who have had their gall bladders removed. (Gall bladders store bile, which helps the body digest fats.)
    • For the wine, researchers found an organic vintage from an English vineyard dating from the Anglo-Saxon period.
    • The two most everyday items (garlic and leek) were actually the most difficult to obtain, and researchers had to “hope for the best.” Why? Modern crop varieties are quite different from ancient ones, even those branded as “organic” or “heritage.”


  • According to the CNN article, researchers used two methods to test the leechdom: on biofilms and in vivo. What’s the difference?
    • The original test, conducted in England, was done on biofilm, meaning a thin coat (film) of MRSA bacteria was spread on laboratory test tubes and slides. The leechdom obliterated the superbug in this controlled environment.
    • American researchers replicated the test in vivo. In vivo simply means the leechdom was tested on living organisms. (In this case, lab mice with infected wounds.) Again, the leechdom killed 90% of the MRSA—about the same efficacy as vancomycin, the antibiotic generally used to treat MRSA.


  • Researchers aren’t sure why the medieval leechdom works, but they have two theories. What are they? Watch the video or read the CNN article for some help.
    • The ingredients are working together. There might be several active components in the mixture that work to attack the MRSA cells on different fronts, making it very hard for the bacteria to resist.
    • The ingredients combine to make a new chemical compound. By combining the ingredients and leaving them in alcohol, a new, more potent bacteria-fighting molecule is created.


  • Think about the careers involved in this amazing discovery. How many can you name?
    • historians (Anglo-Saxonists)
    • linguists (the leechbook was written in Old English, which looks like this (that’s Beowulf, btw))
    • microbiologists
    • lab techs
    • farmers
    • vinters
    • ranchers
    • chemists
    • medical professionals, such as doctors and nurses



CNN: Thousand-year-old Anglo-Saxon potion kills MRSA superbug

University of Nottingham: The AncientBiotics Project video

Nat Geo: MRSA

(extra credit!) British Journal of General Practice: The medical practitioner in Anglo-Saxon England

2 responses to “Medieval Potion Kills Modern Superbug

  1. Pingback: 11 Things We Learned This Week | Nat Geo Education Blog·

  2. Pingback: Medieval Potion Kills Modern Superbug | Nat Geo Education Blog | redlegagenda·

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