Snails in medicine – past and present

By Claire Burridge 

A treatment for teary eyes (Ad lacrimas oculorum):

Grind together frankincense, mastic, and snails with their shells. Apply to the forehead in laurel leaves in two parts. It is tried and tested.

(Tus et mastice et cocleas cum testas sua simul teris et in folio lauri in duabus partibus fronte impone probatum est)

Figure 1: A group of recipes for teary eyes (Ad lacrimas oculorum) in St. Gallen, Stiftsbibliothek, Cod. Sang. 44 (p. 359), an early medieval composite manuscript (this section was written in northern Italy in the ninth century) – the snail recipe is the last entry of the group (found on the final two lines). The transcription and translation are my own. A digitised facsimile can be accessed here; full reference below.

Medieval medicine is often assumed to be full of ‘hocus pocus’: irrational magical and religious cures, bizarre potions and lotions. Although the work of many scholars has countered this common perception, the negative stereotypes surrounding medieval medicine remain firmly embedded in the popular imagination. And I must admit that, as a historian of medieval medicine, I can understand how such stereotypes have persisted – despite, of course, disagreeing! At first glance, the treatment for teary eyes listed above – which recommends making a poultice from snails, frankincense, and mastic and applying it to the forehead – may sound more like a potion brewed by the witches of Macbeth than a useful medical prescription. Surely snails are better suited to escargot than medicine, right?

Yet our slimy garden neighbours actually have long been included as ingredients in medical recipes, from classical antiquity to the present day. In fact, a number of other RP posts have already touched on pre-modern snail-based prescriptions, such as Laura Mitchell’s post on amusing charms, Lisa Smith’s post on Mary Napier’s ‘Snaile Milke’, and Jennifer Sherman Roberts’ post on snail waters. While several examples have highlighted the use of snails in cosmetic preparations, including Katherine Allen’s post on animal ingredients in the eighteenth century, in my research on early medieval recipes I have come across snails as ingredients in treatments for all sorts of ailments, from headaches and nosebleeds to diarrhoea, spleen pain, and incontinence. Who knew snails were seen to be such a wonderful panacea?!

I have been particularly struck by the use of snails in a number of different treatments for cuts and open wounds. A recipe in BAV pal. lat. 1088, a ninth-century manuscript written around Lyon, suggests the following to heal ‘cut tendons’ (Ad neruos incisos) on f. 45r:

Burn and pound together live snails with their shells, add an equal amount of frankincense, apply. It heals cut tendons.

(Cocleas uiuas cum testa sua combustas et tonsas adiecto libano paripondere inponis praecisos neruos sanat)

Two other ninth-century manuscripts in the Stiftsbibliothek St Gallen, Cod. Sang. 751 and Cod. Sang. 759, contain nearly identical prescriptions, though the former recommends either slugs (limacis) or snails and the latter specifies that the cut was caused by iron (Ad neruus ferro precisus). Similar recipes can also be found in earlier sources, such as Pliny’s Natural History and its late antique descendent, the Medicina Plinii, as well as Dioscorides’ De materia medica.

Why did this tradition of the wound-healing power of snails catch my eye?

Figure 2: Materia medica on the move (slowly) – photograph by author.

As keen RP readers will know, the use of snails in cosmetics was not limited to pre-modern medicine but is, in fact, growing in popularity today (and you can read more on this in another piece from Katherine Allen). Snail slime, the mucus secreted by snails, has been widely marketed as a great addition to skincare products. You can find it in anti-aging serums, moisturisers, and other restorative cosmeceuticals. Given these uses, could snail slime also have applications in medicine? Indeed, snail slime is a hot topic in modern medical research, with recent work highlighting its many benefits, from helping to treat burns to its antimicrobial properties. With respect to wound healing, there are several significant features to note: first, snail mucus is well known to have agglutinant, adhesive properties. More recently, however, research has shown that it also protects against apoptosis (programmed cell death) and promotes cell migration and proliferation – processes essential to wound repair at the cellular level. The combination of snail mucus’ adhesive qualities, promotion of healing processes, and antimicrobial properties is immensely exciting, especially in the fight against antibiotic resistance.

While premodern medical practitioners and authors would not have been thinking about snails and their slime on the cellular level or as antimicrobial agents, their repeated use of snails and slugs, especially with respect to skin-related conditions (wound healing, cosmetics, etc.) suggests that they may have recognised that snail mucus had some medical benefits. So, the next time you encounter someone ridiculing the unusual or unpleasant ingredients in a medieval recipe, you can share with them the long history of snails in medicine – from medieval recipes and their ancient antecedents to current, cutting-edge research.

Full reference for manuscript image

St. Gallen, Stiftsbibliothek, Cod. Sang. 44: parchment, 368 pp., 30 x 21 cm; Part I: Bible, consisting of Ezekiel, minor prophets, Daniel, with Prologues and Capitula – given to St. Gall around 780; Part II: collection of medical texts – written in northern Italy in the ninth century.

Brief Academic Biography

Claire Burridge is currently a Residential Research Fellow at the British School at Rome. She completed her PhD at the University of Cambridge in 2019 and will begin a Leverhulme Trust Early Career Fellowship at the University of Sheffield in May 2021. Broadly, Claire works on early medieval health and medicine and is particularly interested in exploring questions of medical practice and the transmission of medical knowledge during the Carolingian period. Her research draws on a range of disciplines, bringing together textual, archaeological, and biocodicological evidence.

Pain, poison, and surgery in fourteenth-century China

Yi-Li Wu

It’s hard to set a compound fracture when the patient is in so much pain that he won’t let you touch him. For such situations, the Chinese doctor Wei Yilin (1277-1347) recommended giving the patient a dose of “numbing medicine” (ma yao).  This would make him “fall into a stupor,” after which the doctor could carry out the needed surgical procedures: “using a knife to cut open [flesh], or using scissors to cut away the sharp ends of bone.” Numbing medicine was also useful when extracting arrowheads from bones, Wei said, enabling the practitioner to “use iron tongs to pull it out, or use an auger to bore open [the bone] and thus extract it.” More generally, Wei recommended using numbing medicines for all fractures and dislocation, for it would allow the doctor to manipulate the patient’s body at will.

Wei’s preferred numbing medicine was “Wild Aconite Powder” (cao wu san), and he detailed the recipe in his influential compendium, Efficacious Formulas of a Hereditary Medical Family (Shiyi dexiao fang), completed in 1337 and printed by the Imperial Medical Academy of the Yuan dynasty (1271-1368). In his preface, Wei affirmed that medical formulas were the foundation of medicine and that a doctor’s ability to cure depended on his ability to use these tools skillfully. Wei’s family had practiced medicine for five generations, and he synthesized their knowledge with that of other doctors to produce a comprehensive treatise encompassing internal medicine; the diseases of women and children; eye diseases; illnesses of the mouth, teeth, and throat; ulcers and swellings; and diseases caused by invasions of “wind” (ailments with sudden onset, including febrile epidemics and paralytic strokes). Numbing medicine appeared in Wei’s chapters on bone setting and weapon wounds.

Wei’s Wild Aconite Powder is the earliest datable recipe that I have found for surgical anesthesia in a Chinese text, and it is a valuable window onto practices that were largely transmitted orally, whether in medical families or from master to disciple.  Dynastic histories relate that the legendary doctor Hua Tuo (110-207) employed a formula called mafeisan  to render his patients insensible prior to cutting them, even opening up their abdomens to excise rotting flesh and noxious accumulations. Some scholars have hypothesized that mafeisan (literally “hemp-boil-powder) may have contained morphine or cannabis (ma), but its ingredients remain a mystery.  A text attributed to the twelfth-century physician Dou Cai (ca. 1146) recommended using a mixture of powdered cannabis and datura flowers (shan qie zi, also called man tuo luo hua) to put patients to sleep prior to moxibustion treatments, which in this text could involve a hundred or more cones of burning mugwort placed directly on the patient’s skin.  Wei Yilin’s recipe provides important additional textual evidence for a tradition of anesthetic formulas based on toxic plants, one that was clearly in circulation long before he wrote it down.

At least as far back as the Divine Farmer’s Classic of Materia Medica (3rd c.), medical authors had described aconite as highly toxic (for contemporary Roman views of aconite, see blogpost by Molly Jones-Lewis). In the right hands, however, aconite was a powerful drug, and part of the Chinese practice of using poisons to cure (see blogpost by Yan Liu).  Warm and acrid, aconite could drive out pathogenic wind and cold from the body, break up stagnant accumulations, and invigorate the body’s vitalities. In the language of Chinese yin-yang cosmology, it nourished yang—all that was active, heating, external, and ascending. The main aconite root was considered more toxic than the subsidiary roots (designated by the separate name fu zi, “appended offspring”), and the wild form was more potent than the cultivated variety.

Images of toxic medicinal plants from China’s most celebrated pharmacological work, Li Shizhen (1518-93), Compendium of Materia Medica (author’s preface dated 1590). Woodblock edition of 1603. Wild aconite is the middle image in the top row. Cultivated aconite (main and subsidiary roots) are in the bottom right corner. Image credit: National Library of China. Posted on-line at the World Digital Library.
Images of toxic medicinal plants from China’s most celebrated pharmacological work, Li Shizhen (1518-93), Compendium of Materia Medica (author’s preface dated 1590). Woodblock edition of 1603. Wild aconite is the middle image in the top row. Cultivated aconite (main and subsidiary roots) are in the bottom right corner. Image credit: National Library of China. Posted on-line at the World Digital Library.

Wei’s numbing recipe consisted of 13 plant ingredients, including the main roots of both wild and cultivated (Sichuanese) aconite, along with drugs known as good for treating wounds:

Young fruit of the honey locust (zhu yao zao jiao)
Momordica seeds (mu bie zi)
Tripterygium (zi jin pi)
Dahurian angelica (bai zhi)
Pinellia (ban xia)
Lindera (wu yao)
Sichuanese lovage (chuan xiong)
Aralia (tu dang gui)
Sichuanese aconite (chuan wu)
Five taels each[1]

Star anise (bo shang hui xiang)
“Sit-grasp” plant (zuo ru), simmered in wine until hot
Wild aconite (cao wu)
Two taels each

Costus (mu xiang), three mace

Combine the above ingredients. Without pre-roasting, make into a powder. In all cases of crushed or broken or dislocated bones, use two mace, mixed into high quality red liquor.

Wei most likely learned this formula from his great-uncle Zimei, a specialist in bonesetting and wounds. Its local origins are also suggested by its use of zuo ru, literally “sit-grasp”, a toxic plant whose botanical identity is unclear. However, according to the eighteenth-century Gazetteer of Jiangxi (Jiangxi tong zhi), sit-grasp was native to Jiangxi, Wei’s home province, and was used by indigenes to treat injuries from blows and falls.  While classical pharmacology focused on the curative effects of aconite, Wei’s anesthetic relied on aconite’s ability to stupefy and numb, while curbing its ability to kill. If an initial dose failed to make the patient go under, Wei said, the doctor could carefully administer additional doses of wild aconite, sit-grasp herb and the datura flower.

Additional images of toxic medicinal plants from Li Shizhen, Compendium of Materia Medica. Sit-grasp herb is in the middle of the top row, and datura flower in the middle of the bottom. Image credit: National Library of China. Posted on-line at the World Digital Library.
Additional images of toxic medicinal plants from Li Shizhen, Compendium of Materia Medica. Sit-grasp herb is in the middle of the top row, and datura flower in the middle of the bottom. Image credit: National Library of China. Posted on-line at the World Digital Library.

In subsequent centuries, as medical texts proliferated, we find additional examples of numbing medicines that employed aconite, datura, and other toxic plants, employed when setting bones and draining abscesses, and to numb injured flesh before repairing tears and lacerations to ears, noses, lips, and scrotums.  Such manual and surgical therapies are an integral part of the history of healing in China.

Yi-Li Wu is a Center Associate of the Lieberthal-Rogel Center for Chinese Studies at the University of Michigan, Ann Arbor (US) and an affiliated researcher of EASTmedicine, University of Westminster, London (UK).  She earned a Ph.D. in history from Yale University and was previously a history professor at Albion College (USA) for 13 years.  Her publications include Reproducing Women: Medicine, Metaphor, and Childbirth in Late Imperial China (University of California Press, 2010) and articles on medical illustration, forensic medicine, and Chinese views of Western anatomical science.  She is currently completing a book on the history of wound medicine in China.

Acknowledgements
This research was funded by the Wellcome Trust Medical Humanities Award “Beyond Tradition: Ways of Knowing and Styles of Practice in East Asian Medicines, 1000 to the present” (097918/Z/11/Z). I am also grateful to Lorraine Wilcox for directing me to the work of Dou Cai.

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[1] The weight of the tael (Ch. liang) has varied over time, but during Wei’s lifetime would have been equivalent to 40 grams.  A mace (Ch. qian) is one-tenth of a tael.