In the world of medieval medicine, few plants straddled the line between nuisance and remedy quite like the humble nettle. Prickly, pervasive, and painful to the touch, Urtica dioica—commonly known as the stinging nettle—was both feared and valued in medieval Europe. A new study by Dr. Erin Connelly and Dr. Christina Lee explores the long history of nettles in medieval healing practices, and how these ancient remedies compare with modern scientific understanding.
Their research, recently published in Medicine in the Medieval North Atlantic World, combines the expertise of historians, microbiologists, and data scientists. Drawing on 139 recipes from thirty medieval manuscripts in Latin, Old English, Middle English, and Welsh, the study traces how nettles were used to treat a wide variety of ailments.
The authors began with a deceptively simple question posed in a ninth-century garden text: Quid facerem? (“What should I do?”) — the lament of a monk named Strabo finding his garden overrun by nettles. While for many, the answer would be to pull them out by the root, medieval healers often saw potential in the sting.
“Nettles are ubiquitous in medieval and modern settings and were part of the pharmaceutical kit used across the period,” Connelly and Lee write. “They are a nuisance to some authors, and a vital part of healing processes to others. So, Strabo’s question arises again: what should we do with nettles?”
Their answer comes from both the past and the lab.
Nettles in Medieval Remedies
Nettles are a common plant in Europe – photo by Joanna Boisse / Wikimedia Commons
Though painful to handle, nettles were a staple ingredient in many medieval remedies, especially for skin wounds, inflammation, animal bites, and swelling. In texts like the Old English Herbarium, Lacnunga, and Henry of Huntingdon’s Anglicanus ortus, nettles appear frequently, often mixed with vinegar, fats, or salt.
One Middle English medical text offers the following recipe:
Stamp nettle leaves with salt and make thereof a plaster and it will cleanse foul wounds and do good to bocches. This plaster is good against hound bites and cancres and the sickness that men call parotida.
A more elaborate recipe from the Master of Game, a fifteenth-century hunting manual, outlines a potent mixture designed to treat dog bites:
There is another help, for men may make sauce of salt, vinegar and strong garlic pulled and stamped, and nettles together and as hot as it may be suffered to lay upon the bite. And this is a good medicine and a true, for it hath been proved, and every day should it be laid upon the biting twice, as hot as it can be suffered, until the time when it be whole, or else by nine days.
These recipes reflect a pragmatic and empirical approach to healing, even if they sit alongside charms and prayers in the manuscripts. Far from being purely superstitious, the remedies often indicate careful observation and accumulated knowledge of plant behaviour, soil conditions, and preparation techniques.
The authors note that medieval healers understood that “soil conditions can influence aspects of plant chemistry,” and that specific gathering instructions—such as choosing red nettles growing through a building (‘seo ræde netele ðe þurh ærn inwyxð’).—may have reflected experiential knowledge of plant potency.
From Texts to Tests
Nettles were often drawn in medieval texts – British Library MS Egerton 747, fol. 104r
But how effective were these remedies? To answer this, Connelly and Lee, working with microbiologist Dr. Freya Harrison, subjected medieval nettle-based recipes to laboratory testing. Their focus was on wound care: mixtures of fresh nettles prepared in vinegar, butter, or olive oil, as described in the manuscripts, were tested against two common bacteria—Staphylococcus aureus and Pseudomonas aeruginosa.
Their findings were striking. Nettles themselves showed no measurable antibacterial activity. However, when soaked in vinegar, the nettles acted like a sponge, delivering the acetic acid—well known for its antimicrobial properties—directly to the infection site.
“The nettles had no effect on viable bacteria numbers themselves, but were able to carry sufficient vinegar with them to completely eradicate the bacterial populations,” they explain. “All replicates of nettle + vinegar and vinegar treatments for both species had viable cell numbers below the limit of detection by plating.”
In other words, while the nettles may not have healed the wound, they could have helped deliver the healing. This opens up a new way of understanding medieval medicine: not just in terms of plant chemistry, but in terms of preparation, delivery, and design.
Yesterday, Warwick held a public festival of arts & culture. @tosinorababa.bsky.social, Erin Connelly and I had an excellent day talking about historical medicine, alchemy and the modern-day science we’re doing as part of the #Ancientbiotics collaboration. #SciComm
Nettles were everywhere in medieval Europe. They grew wild, especially near roads and livestock enclosures, and their sting made them memorable. Yet, beyond their medicinal use, nettles were also a source of food, animal fodder, fertilizer, and textile fibres.
Unlike many cultivated herbs, nettles haven’t been significantly modified by human breeding over the centuries. This makes them ideal subjects for comparing medieval and modern applications.
While modern herbal shampoos and dietary supplements continue to use nettles, often claiming benefits for hair, blood, and skin, the authors caution that scientific backing is limited. Their systematic review found that most modern studies used dried nettle material, not fresh, and none replicated the vinegar- or fat-based preparations seen in medieval recipes.
That’s a missed opportunity. “Following the historical recipe instructions has proved critical in observing successful activity,” the authors write, citing the celebrated example of “Bald’s eyesalve,” a thousand-year-old remedy shown to kill MRSA in lab trials.
Future Research
Although nettles may not be miracle antimicrobials, the study emphasizes that their value may lie in other properties. Some evidence points to anti-inflammatory or immunomodulatory effects, and lipophilic extracts (made using oils or fats) may hold potential in treating conditions like arthritis. Dead-nettles (Lamium spp.), which also appear frequently in medieval recipes, remain largely unexplored in scientific literature.
The researchers argue that more attention should be paid to how remedies were prepared, not just what ingredients were used. By recreating these methods, researchers hope to uncover “shortcuts” to new treatments or delivery mechanisms that may still have value today.
The article, “Menace or Medicine: What to do with Nettles?,” by Erin Connelly and Christina Lee, appears in Medicine in the Medieval North Atlantic World: Vernacular Texts and Traditions, edited by Deborah Hayden and Sarah Baccianti. You can read it through BrepolsOnline.
In the world of medieval medicine, few plants straddled the line between nuisance and remedy quite like the humble nettle. Prickly, pervasive, and painful to the touch, Urtica dioica—commonly known as the stinging nettle—was both feared and valued in medieval Europe. A new study by Dr. Erin Connelly and Dr. Christina Lee explores the long history of nettles in medieval healing practices, and how these ancient remedies compare with modern scientific understanding.
Their research, recently published in Medicine in the Medieval North Atlantic World, combines the expertise of historians, microbiologists, and data scientists. Drawing on 139 recipes from thirty medieval manuscripts in Latin, Old English, Middle English, and Welsh, the study traces how nettles were used to treat a wide variety of ailments.
The authors began with a deceptively simple question posed in a ninth-century garden text: Quid facerem? (“What should I do?”) — the lament of a monk named Strabo finding his garden overrun by nettles. While for many, the answer would be to pull them out by the root, medieval healers often saw potential in the sting.
“Nettles are ubiquitous in medieval and modern settings and were part of the pharmaceutical kit used across the period,” Connelly and Lee write. “They are a nuisance to some authors, and a vital part of healing processes to others. So, Strabo’s question arises again: what should we do with nettles?”
Their answer comes from both the past and the lab.
Nettles in Medieval Remedies
Though painful to handle, nettles were a staple ingredient in many medieval remedies, especially for skin wounds, inflammation, animal bites, and swelling. In texts like the Old English Herbarium, Lacnunga, and Henry of Huntingdon’s Anglicanus ortus, nettles appear frequently, often mixed with vinegar, fats, or salt.
One Middle English medical text offers the following recipe:
Stamp nettle leaves with salt and make thereof a plaster and it will cleanse foul wounds and do good to bocches. This plaster is good against hound bites and cancres and the sickness that men call parotida.
A more elaborate recipe from the Master of Game, a fifteenth-century hunting manual, outlines a potent mixture designed to treat dog bites:
There is another help, for men may make sauce of salt, vinegar and strong garlic pulled and stamped, and nettles together and as hot as it may be suffered to lay upon the bite. And this is a good medicine and a true, for it hath been proved, and every day should it be laid upon the biting twice, as hot as it can be suffered, until the time when it be whole, or else by nine days.
These recipes reflect a pragmatic and empirical approach to healing, even if they sit alongside charms and prayers in the manuscripts. Far from being purely superstitious, the remedies often indicate careful observation and accumulated knowledge of plant behaviour, soil conditions, and preparation techniques.
The authors note that medieval healers understood that “soil conditions can influence aspects of plant chemistry,” and that specific gathering instructions—such as choosing red nettles growing through a building (‘seo ræde netele ðe þurh ærn inwyxð’).—may have reflected experiential knowledge of plant potency.
From Texts to Tests
But how effective were these remedies? To answer this, Connelly and Lee, working with microbiologist Dr. Freya Harrison, subjected medieval nettle-based recipes to laboratory testing. Their focus was on wound care: mixtures of fresh nettles prepared in vinegar, butter, or olive oil, as described in the manuscripts, were tested against two common bacteria—Staphylococcus aureus and Pseudomonas aeruginosa.
Their findings were striking. Nettles themselves showed no measurable antibacterial activity. However, when soaked in vinegar, the nettles acted like a sponge, delivering the acetic acid—well known for its antimicrobial properties—directly to the infection site.
“The nettles had no effect on viable bacteria numbers themselves, but were able to carry sufficient vinegar with them to completely eradicate the bacterial populations,” they explain. “All replicates of nettle + vinegar and vinegar treatments for both species had viable cell numbers below the limit of detection by plating.”
In other words, while the nettles may not have healed the wound, they could have helped deliver the healing. This opens up a new way of understanding medieval medicine: not just in terms of plant chemistry, but in terms of preparation, delivery, and design.
Why Nettles?
Nettles were everywhere in medieval Europe. They grew wild, especially near roads and livestock enclosures, and their sting made them memorable. Yet, beyond their medicinal use, nettles were also a source of food, animal fodder, fertilizer, and textile fibres.
Unlike many cultivated herbs, nettles haven’t been significantly modified by human breeding over the centuries. This makes them ideal subjects for comparing medieval and modern applications.
While modern herbal shampoos and dietary supplements continue to use nettles, often claiming benefits for hair, blood, and skin, the authors caution that scientific backing is limited. Their systematic review found that most modern studies used dried nettle material, not fresh, and none replicated the vinegar- or fat-based preparations seen in medieval recipes.
That’s a missed opportunity. “Following the historical recipe instructions has proved critical in observing successful activity,” the authors write, citing the celebrated example of “Bald’s eyesalve,” a thousand-year-old remedy shown to kill MRSA in lab trials.
Future Research
Although nettles may not be miracle antimicrobials, the study emphasizes that their value may lie in other properties. Some evidence points to anti-inflammatory or immunomodulatory effects, and lipophilic extracts (made using oils or fats) may hold potential in treating conditions like arthritis. Dead-nettles (Lamium spp.), which also appear frequently in medieval recipes, remain largely unexplored in scientific literature.
The researchers argue that more attention should be paid to how remedies were prepared, not just what ingredients were used. By recreating these methods, researchers hope to uncover “shortcuts” to new treatments or delivery mechanisms that may still have value today.
The article, “Menace or Medicine: What to do with Nettles?,” by Erin Connelly and Christina Lee, appears in Medicine in the Medieval North Atlantic World: Vernacular Texts and Traditions, edited by Deborah Hayden and Sarah Baccianti. You can read it through BrepolsOnline.
Erin Connelly (University of Warwick) and Christina Lee (University of Nottingham) are well known for their research into medieval medicines. You can read more about their project, Nettles and Networks: New Ways to Tackle Wound Infections.
Top Image: BnF Latin 6823, fol.161v
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