Paracelsus's Medicines: Minerals, Herbs and Spagyric Extracts

Table of Contents

1. Salt, Sulphur and Mercury: The Three Principles
2. Alchemy Turned Toward Medicine
3. Separating the Remedy from the Poison
4. Mercury and the Treatment of Syphilis
5. The Guaiac Wood Controversy of 1529
6. Laudanum: An Attribution and a Doubt
7. Sweet Vitriol, Sleeping Chickens and Ether
8. Antimony, Arsenic, Vitriol and the Naming of Zinc
9. Herbs, Plague Remedies and the Doctrine of Signatures
10. How His Remedies Compare With Later Pharmacology
11. Key Research Papers
12. Connections
13. Featured Videos

1. Salt, Sulphur and Mercury: The Three Principles

Medicine in the early sixteenth century still rested on the ancient theory of four elements (earth, water, air and fire) and four bodily humours (blood, phlegm, yellow bile and black bile). Illness was read as an imbalance of humours, and treatment aimed to restore the balance — by diet, bleeding, purging, and compound plant medicines chosen for their “hot”, “cold”, “wet” or “dry” qualities.

Paracelsus did not throw the elements away, but he laid a new scheme over them that came out of the alchemical workshop. Every material thing, he taught, could be resolved into three principles, the tria prima:

• Sulphur — the principle of combustibility, the part of a body that burns;
• Mercury — the principle of liquidity and volatility, the part that flows or rises as vapour;
• Salt — the principle of stability and solidity, the part left behind as ash.

These were not the ordinary substances sold under those names; they were qualities, and the watching chemist could see them separate when a piece of wood burned (the flame was its sulphur, the smoke and vapour its mercury, the ash its salt). In the summary of the toxicologist M. F. Wilks, Paracelsus held that the properties of the three principles could be harnessed to prepare specific medicines, and that poisons could become medicines because it is the dose that determines toxicity. A 2021 review by Michaleas and colleagues in Toxicology Reports describes the same scheme as the theoretical base for his use of mineral remedies.

The practical consequence was large. If a disease was a disturbance of the body’s chemistry rather than a mere surplus of a humour, then the remedy could be a chemical agent aimed at that disturbance — and the best place to find such agents was among the minerals and metals that the humoral physicians mostly kept out of the mouth. The idea that a medicine acts on a particular disease, rather than on a general imbalance, is one reason historians place him among the founders of chemical pharmacology (the story of how the three-principle theory spread after his death belongs to the Legacy page).

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2. Alchemy Turned Toward Medicine

Alchemy in his century had two aims that were often mixed together: turning base metals into gold, and preparing powerful substances by distillation, calcination (burning to ash), dissolution and crystallisation. Paracelsus did believe that metals could be transmuted — the historian of science A. W. Sparling, studying his treatise De renovatione et restauratione, shows how he wrote about “first entities” that could renew metals and people alike. But his famous turn was to say that the true work of alchemy was making medicines, not gold.

He carried the alchemist’s picture inside the body as well. The nutrition historian K. Y. Guggenheim, writing for the five-hundredth anniversary of his birth, explains that Paracelsus imagined an inner “alchemist” (the archeus of his writings) in each organ, separating the useful part of food from the waste and turning food into body substance. Digestion, in this picture, was a chemical refining process, and disease could follow when the inner alchemist failed. Guggenheim treats this as an early step toward a chemical understanding of nutrition, even though the details were wrong by any modern measure.

The laboratory language he used has survived in odd places. The word spagyric, which became attached to Paracelsian medicine, is usually explained as joining Greek roots for “drawing apart” and “bringing together” — the two halves of the alchemical method, first separating a material into its parts and then recombining the purified parts into a medicine. Alongside it come arcanum (a hidden, specific healing virtue, plural arcana) and quinta essentia (the “fifth essence” or quintessence, the concentrated active part of a substance).

This blend of laboratory practice with astrology, theology and natural magic is part of what makes Paracelsus hard to summarise. The historian Allen Debus titled one of his studies of the movement “Paracelsus and the chemical revolution in sixteenth-century medicine”; at the same time, the men who carried out that revolution often believed in the philosopher’s stone. Both things are true at once, and this page reports them without ridicule and without endorsement.

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3. Separating the Remedy from the Poison

The central promise of Paracelsian pharmacy was that fire could divide a substance. In the account of the historian Walter Pagel, Paracelsus sought the quinta essentia or arcanum of each material by breaking drugs into their component parts — and the part he wanted was the healing virtue, freed from the coarse and poisonous matter that surrounded it. The historian E. K. Hunter, writing in Social History of Medicine in 2022, traces how this Paracelsian idea of separating medicine from poison shaped how English physicians of the late sixteenth and seventeenth centuries thought about dangerous sleep-inducing drugs.

Sparling’s study of De renovatione et restauratione shows the idea at its most ambitious. There Paracelsus wrote of prima entia, “first entities”, prepared from plants, gems, metals and minerals, which were meant to revitalise the body as the same kind of preparation could, he believed, renew a metal. Sparling calls them “wonder drugs for metals and for people” — a phrase that captures both the reach of the hope and its distance from anything later chemistry could support.

The same reasoning sits behind his defence of strong remedies in the 1538 Seven Defences. If what makes a medicine poisonous is partly its crude form and partly its amount, then a skilled preparer could change both. The dose principle itself, with his original wording, is told on the companion page Paracelsus and the Dose Makes the Poison; what matters here is that for Paracelsus “dose” was never only a number of grains. It was the amount and the preparation together.

An idea with a modern echo

Writers on the history of pharmacology often point out a loose resemblance between the quintessence and the much later idea of an “active principle” — the single compound responsible for a plant’s effect, such as morphine purified from opium in the early nineteenth century. The resemblance is real but limited. Paracelsus had no way to isolate or identify a compound; his separations were guided by colour, smell, taste and theory, and the products of a furnace can be more toxic, not less, than the raw material. The comparison is one of ambition rather than method.

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4. Mercury and the Treatment of Syphilis

Syphilis swept through Europe from the 1490s, in the same years Paracelsus was born. It was a new and terrifying disease to the physicians of the time: a spreading rash, ulcers, bone pain, and in its later stages damage to the brain, heart and skeleton. The bacterium that causes it, Treponema pallidum, would not be identified until 1905 (see Syphilis).

Mercury was not new to medicine. As Michaleas and colleagues describe, it was already used in medicine mixed with fats, as an ointment. What Paracelsus did, in their words, was to expand its use to treat syphilis and dropsy (the old name for swelling caused by fluid build-up). He also argued for internal mercury preparations made in the laboratory, at a time when many physicians considered swallowing a metal reckless.

Mercury became the standard European treatment for syphilis for roughly four centuries — long enough to give rise to the grim saying “a night with Venus, a lifetime with Mercury.” A 2022 review of mercury-containing medicines by Zhao and colleagues notes that in India and Europe mercury was often used for treating syphilis, and J. Stephenson’s 2025 history in Sexually Transmitted Infections follows the line of syphilis treatments from mercury to penicillin.

What the treatment did to patients

The harms were visible even then. Mercury treatment produced heavy salivation, loosened teeth, mouth ulcers, tremor and kidney damage, and patients could die of the cure. Modern toxicology describes mercury compounds as nerve and kidney poisons, and the environmental health researcher Philippe Grandjean names mercury as one of the substances where the right dose limit is still debated today. Whether mercury did much against the syphilis bacterium itself is uncertain; the disease naturally passes through quiet phases that could be mistaken for cure. The Zurich Paracelsus Project suggests that Paracelsus himself may have died of chronic mercury poisoning, though this is an inference, not a documented finding.

His own position was that mercury in the right preparation and amount could heal, and in excess would kill — the exact argument he set out in 1538. Read in that light, the syphilis debate was the practical test of his whole theory.

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5. The Guaiac Wood Controversy of 1529

Mercury had a rival. From the first decade of the sixteenth century, wood of the guaiacum tree, shipped from the Caribbean island of Hispaniola, was sold in Europe as a cure for syphilis. Historians of pharmacology describe it as the first drug used against syphilis in Europe. The treatment came with a punishing regime — enemas and up to forty days of sweating in a hot, dark room — and the imported wood was expensive.

In 1529, in Nuremberg, Paracelsus published a critical appraisal of the guaiac cure, Von Holtz Guaiaco gründlicher heylung (“On the thorough healing by guaiac wood”), as part of his writing on syphilis. Pagel’s biography records it among his Nuremberg works. Paracelsus judged the wood ineffective and its popularity unearned, and he set his mercury preparations against it.

The aftermath is told in later histories rather than in documents we have checked directly. According to those accounts, a protest from the Leipzig medical faculty stopped the printing of his further syphilis writings, and the controversy deepened his reputation as a troublemaker among the learned physicians. Some popular accounts add a commercial motive for the opposition; this page does not repeat that claim, because the primary sources behind it have not been verified here.

On the medical point, later experience sided with Paracelsus more than with the guaiac traders: guaiac fell out of use as a syphilis cure, while mercury stayed. Neither was effective by modern standards, and both were replaced in the twentieth century — first by arsenic compounds, then by penicillin (section 10).

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6. Laudanum: An Attribution and a Doubt

Paracelsus is very often named as the inventor of laudanum, the opium tincture that became one of the most widely used medicines of the eighteenth and nineteenth centuries. The 2021 review by Michaleas and colleagues in the Journal of Religion and Health states that he is credited with developing the first recipe for laudanum, an opium-based pain medicine. The claim appears in countless histories of pain relief.

The historian E. K. Hunter, studying early modern English sleep medicines, adds an important doubt. In her 2022 paper she writes that while the invention of laudanum is attributed to Paracelsus, his version was unlikely to have borne much resemblance to later versions, and probably did not contain opium. She notes that some very early recipes going by the name used henbane, another sleep-inducing plant, rather than opium. The word laudanum itself is often explained as coming from the Latin for “to praise”.

So the fair statement is two-sided: Paracelsus used the name for a celebrated remedy of his own, later tradition credits him with inventing laudanum, and the best recent historical work suggests that what he made was not the opium medicine the word came to mean. The later, opium-based laudanum, and the dependence it caused, are part of the long story told on the site’s History of Chronic Pain and History of Insomnia pages. This page gives no preparation details.

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7. Sweet Vitriol, Sleeping Chickens and Ether

One of the most quoted stories in the history of anaesthesia concerns a substance the alchemists called “sweet oil of vitriol” — what chemists now call diethyl ether, formed when alcohol is heated with sulphuric acid (then known as oil of vitriol). Its first clear preparation is usually credited to the German botanist and pharmacist Valerius Cordus, around 1540.

Historians of anaesthesia credit Paracelsus with an observation about the same substance: that chickens given sweet vitriol fell asleep and later woke unharmed, and that it seemed to quiet pain. The anaesthesiologist J. S. Gravenstein reviewed this and his other claimed contributions in Anesthesiology in 1965. The chicken story has been retold so often that its exact source in his writings is rarely given, so this page reports it as the historians’ account rather than as a documented experiment.

What is certain is that nothing came of it for three centuries. Ether was used as a solvent and a medicine for other purposes, and it was not until the 1840s, in the United States, that it was used to put patients to sleep for surgery. The gap is a reminder that an early observation, however striking in retrospect, is not the same as a discovery that changes practice.

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8. Antimony, Arsenic, Vitriol and the Naming of Zinc

Beyond mercury, Paracelsus and the chemists who followed him worked with a cabinet of mineral substances that the humoral physicians regarded with deep suspicion. Michaleas and colleagues list mercury, antimony and arsenic, used in what he considered “detoxified” forms, among his remedies; Pagel’s biography describes the same turn to inorganic medicines as one of the most controversial features of his practice.

Antimony

Antimony compounds act as powerful emetics and purgatives — they make people vomit and empty the bowels — which suited a medicine that still prized purging. They are also toxic to the heart, liver and gut. In the generations after his death, antimony became one of the most fiercely argued remedies of the Paracelsian movement, with physicians and medical faculties taking sides for and against it (that fight is part of the Legacy story).

Arsenic

Arsenic is the classic poison of history. Its use in medicine is as old as its use in murder, and Paracelsus belongs to a long line of practitioners who believed a prepared form could heal. The line ran on for centuries — to arsenic solutions in the nineteenth century, and to the arsenic-based drug arsphenamine that Paul Ehrlich introduced against syphilis in 1910. Arsenic’s toxicity, including its links to cancer, is laid out on the site’s Arsenic page.

Vitriol

“Vitriol” was the old name for the glassy crystals now known as metal sulphates: green vitriol (iron sulphate), blue vitriol (copper sulphate) and white vitriol (zinc sulphate). Heated, they gave off the acid called oil of vitriol — sulphuric acid. For the Paracelsian chemist, vitriol was both a medicine in its own right and a starting material from which other preparations, including sweet vitriol, could be made.

The naming of zinc

The modern name of the metal zinc is usually traced to Paracelsus, who referred to it as zincum or zinken in his writings on minerals. He is often described as one of the first Europeans to treat it as a distinct metal, though he did not isolate it in any modern sense. The site’s History of Zinc tells how the element was later isolated and, in the twentieth century, recognised as an essential nutrient — a very different place for a mineral that entered European chemistry through the alchemist’s furnace.

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9. Herbs, Plague Remedies and the Doctrine of Signatures

It would be wrong to picture Paracelsus as a man who used only metals. He grew up learning botany from his physician father in Villach, and plants run all through his writings. The historian Bruce Moran devoted a long study to the Herbarius of Paracelsus in Pharmacy in History (1993), and the historian M. Fehér surveyed the plant medicine of his age in 1975. His herbal remedies were often prepared by the same distilling methods as his minerals, so that a “spagyric” plant medicine was meant to carry the concentrated virtue of the herb rather than the leaf itself.

The doctrine of signatures

Paracelsus is closely linked to the doctrine of signatures: the belief that God had marked useful plants with a sign of their purpose. In Pagel’s examples, a yellow plant pointed to the liver (and jaundice), and an orchid’s paired roots to the testicles. In a 2026 paper in the Journal of the History of Ideas, the historian M. Leprêtre argues that the signatures were not decoration but an integral part of Paracelsus’s “localist” understanding of diseases and drug action — a disease seated in one organ was matched by a remedy with an affinity for that organ — rooted in his belief that all Gewächse (growing things, including animals, plants, stones and metals) sprang from an invisible tree planted by God.

The doctrine has not survived as science; plant shapes and colours do not predict their chemistry, as the site’s page on the doctrine of signatures problem explains using lungwort. The ancient idea that “like cures like” also appears in his work, but it is not the same thing as homeopathy, which Samuel Hahnemann founded in the 1790s on different principles.

Three herbs that carry his name in their histories

• St John’s wort. The plant’s perforated leaves and red oil were read through the doctrine of signatures, and Paracelsus singled it out for wounds and for melancholy — the condition for which modern trials, centuries later, would test it. See History of St John’s Wort.
• Lemon balm. Paracelsus is traditionally said to have called lemon balm an “elixir of life”; whether he used those exact words is itself part of the inherited tradition. See History of Lemon Balm.
• Angelica. German histories report that he recommended the root and its distilled oil as a preservative against plague. See History of Angelica.

The plague treatise of 1534

The clearest window on his everyday practice comes from the plague. In 1534 Paracelsus was in the Tyrolean town of Sterzing (now Vipiteno, Italy) during an outbreak and wrote a treatise for the town, Von der Pestilentz an die Statt Stertzingen, first printed in 1576. The historian C. D. Gunnoe, analysing it in Annals of Science in 2025, finds it a practical document offering bloodletting and herbal remedies — far closer to the ordinary medicine of his day than his polemics would suggest. The radical chemist, faced with a town in crisis, reached for the conventional tools as well as his own.

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10. How His Remedies Compare With Later Pharmacology

Measured against modern medicine, most of Paracelsus’s specific remedies were ineffective, dangerous or both. Mercury damaged nerves and kidneys; antimony and arsenic are toxic in ways his methods could not control; the doctrine of signatures has no predictive value. His theory of three principles was replaced by the chemistry of elements and compounds that began in the seventeenth and eighteenth centuries.

Yet several of his ideas point toward the pharmacology that followed:

• Specific remedies for specific diseases. Treating a named disease with an agent aimed at it, rather than rebalancing humours, is the logic of every targeted drug since — most famously Ehrlich’s idea of a “magic bullet”.
• Chemistry as the source of medicines. The laboratory preparation of drugs, which he championed against the herbal tradition of the universities, became the normal way medicines are made.
• Dose and form together. His insistence that the amount and the preparation decide whether a substance heals or harms is the starting point of toxicology, as the companion page on the dose principle explains.

The road from mercury to penicillin

The syphilis story shows how long it took to get from his intuition to a cure. Mercury held the field for about four hundred years. In 1910 Paul Ehrlich’s arsenic compound arsphenamine offered the first drug designed by systematic chemical testing to attack the syphilis organism — still a metal-based poison used at a carefully chosen dose, very much in the Paracelsian line. From the mid-1940s penicillin, a natural product of a mould, replaced both. Stephenson’s 2025 history traces that whole arc.

From signatures to active compounds

For the herbs, the modern question is no longer what a plant looks like but what it contains. St John’s wort, which Paracelsus read through its signature, is now studied for compounds such as hyperforin and hypericin, and for its interactions with prescription drugs; lemon balm and angelica have their own lists of identified constituents. The method changed completely, while some of the plants he valued stayed under study.

The historians’ verdict is therefore mixed in a precise way. Paracelsus was wrong about most of his medicines and right about some of the questions. The plants, metals and salts he worked with are covered in their own pages on this site, with the modern evidence for each; his life is told in Life and Times, and what came after him in Legacy and Later Research.

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Key Research Papers

1. Wilks MF. Bringing Chemistry to Medicine - The Contribution of Paracelsus to Modern Toxicology. Chimia (Aarau). 2020;74(6):507-508. PubMed PMID: 32560760
2. Michaleas SN, Laios K, Tsoucalas G, Androutsos G. Theophrastus Bombastus Von Hohenheim (Paracelsus) (1493-1541): The eminent physician and pioneer of toxicology. Toxicol Rep. 2021;8:411-414. PubMed PMID: 33717994
3. Michaleas SN, Pantos C, Chatzipanagiotou S, Samonis G, Karamanou M. Theophrastus Bombastus Von Hohenheim: Theological Reformer, Philosopher and Physician. J Relig Health. 2021;60(6):3907-3914. PubMed PMID: 33876340
4. Hunter EK. 'To Cause Sleepe Safe and Shure': Dangerous Substances, Sleep Medicine and Poison Theories in Early Modern England. Soc Hist Med. 2022;35(2):473-493. PubMed PMID: 35558657
5. Guggenheim KY. Paracelsus and the science of nutrition in the renaissance. On occasion of the 500th anniversary of his birth. J Nutr. 1993;123(7):1189-94. PubMed PMID: 8320560
6. Sparling AW. First entities in the De renovatione et restauratione of Paracelsus: wonder drugs for metals and for people. Ann Sci. 2025;82(2):312-332. PubMed PMID: 38666321
7. Debus AG. Paracelsus and the chemical revolution in sixteenth-century medicine. Gaz Grolier Club. 2002;53:49-70. PubMed PMID: 16496479
8. Zhao M, Li Y, Wang Z. Mercury and Mercury-Containing Preparations: History of Use, Clinical Applications, Pharmacology, Toxicology, and Pharmacokinetics in Traditional Chinese Medicine. Front Pharmacol. 2022;13:807807. PubMed PMID: 35308204
9. Stephenson J. The Centenary Series - STIs Through the Ages: From mercury to penicillin-a brief history of syphilis treatments. Sex Transm Infect. 2025;101(3):141-143. PubMed PMID: 40234009
10. Grandjean P. Paracelsus Revisited: The Dose Concept in a Complex World. Basic Clin Pharmacol Toxicol. 2016;119(2):126-32. PubMed PMID: 27214290
11. Gravenstein JS. Paracelsus and his contributions to anesthesia. Anesthesiology. 1965;26(6):805-11. PubMed PMID: 5320896
12. Moran BT. The Herbarius of Paracelsus. Pharm Hist. 1993;35(3):99-127. PubMed PMID: 11623167
13. Fehér M. Phytotherapy in the age of Paracelsus. Nord Medicinhist Arsb. 1975:87-92. PubMed PMID: 11626928
14. Leprêtre M. Paracelsus's Doctrine of Signatures Reconsidered. J Hist Ideas. 2026;87(2):225-256. PubMed PMID: 42077073
15. Gunnoe CD. Paracelsus and the Tyrolean Plague Epidemic of 1534: context and analysis of Von der Pestilentz an die Statt Stertzingen. Ann Sci. 2025;82(2):275-296. PubMed PMID: 38587865

PubMed Topic Searches

1. Iatrochemistry
2. Mercury and syphilis: history
3. Paracelsus (title) and history
4. Doctrine of signatures

Further Reading

• Pagel W. “Paracelsus.” Complete Dictionary of Scientific Biography (via Encyclopedia.com). encyclopedia.com
• Zurich Paracelsus Project, University of Zurich — Life and Works. paracelsus.uzh.ch

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Connections

• Paracelsus: The Dose Makes the Poison and the Birth of Chemical Medicine
• Paracelsus: Life and Times of a Renaissance Rebel Physician
• Paracelsus and the Dose Makes the Poison: The 1538 Third Defence
• Paracelsus’s Legacy: Miners’ Disease, the Paracelsians and Modern Toxicology
• Pharmacology Pioneers
• Paul Ehrlich
• Mercury
• Antimony
• Arsenic
• Syphilis
• History of Zinc
• History of St John’s Wort

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