The Canon of Medicine: Five Books of Medieval Medicine

The Canon of Medicine (Arabic al-Qānūn fī al-ṭibb, “the law of medicine”) is the book that made Avicenna — Ibn Sīnā, the Persian physician-philosopher of the early eleventh century — the most-read medical author of the Middle Ages. Written in Arabic and finished in 1025, it gathered the Greek medicine of Galen and Hippocrates, the natural philosophy of Aristotle and two centuries of Arabic medical writing into one ordered work in five books. Two of those books are about medicines: Book 2 describes some 800 “simple” drugs, each one a single plant, mineral or animal substance, and Book 5 is a formulary of about 650 compound remedies.

This page walks through the book itself: where it was written, what it set out to do and which works came before it, what each of the five books contains, the theory of elements, humours and temperaments that framed every drug in it, the place of diet and daily regimen ahead of medicines, how a Book 2 drug entry was laid out, what the Book 5 formulary holds, how often Avicenna followed Galen and where he parted from him, and the poisons and antidotes of Book 4. His rules for testing drugs, which sit in Book 2, have a page of their own, as do his life and the Canon’s long career in Europe. Every dose and recipe in the Canon is reported here as history only.

Table of Contents

  1. Written on the Road, Finished in 1025
  2. A Summa of Greek and Arabic Medicine
  3. The Five Books at a Glance
  4. Elements, Humours and Temperaments
  5. Regimen and Diet Before Drugs
  6. Book 2: Eight Hundred Simple Drugs
  7. Anatomy of a Book 2 Entry
  8. Book 5: The Formulary of Compound Drugs
  9. Agreeing and Arguing with Galen
  10. Poisons and Antidotes in Book 4
  11. Key Research Papers
  12. Connections
  13. Featured Videos

1. Written on the Road, Finished in 1025

The Canon was not written in a quiet library. Avicenna spent his working life moving from court to court across Central Asia and Iran, serving whichever ruler would employ him as physician, administrator or vizier, and the book moved with him. By the usual account he began it in Gurganj, the capital of Khwarazm south of the Aral Sea, where he served the Ma’munid ruler after leaving Bukhara around the collapse of the Samanid state in 999. He continued it in Ray, near present-day Tehran, where from about 1014 he was physician to the Buyid amir Majd al-Dawla, and he completed it in Hamadan in western Iran in 1025. The Encyclopaedia Iranica article on his medicine places the composition of Book 1 before 1015.

Those were unsettled years. In Hamadan he served the ruler Shams al-Dawla as vizier, went into hiding after that ruler’s death in 1021, and was held for about four months in the fortress of Fardajan outside the city before moving on to Isfahan around 1024. The dates of each move are approximate, because the main source for them is his own autobiography and the biography completed by his pupil Abū ‘Ubayd al-Jūzjānī, who travelled with him. During the same years Avicenna was also writing the Book of Healing (Kitāb al-Shifā’), his vast encyclopedia of philosophy and science. The Canon was his medical counterpart to it.

The story of these journeys, the prison at Fardajan and the final years in Isfahan is told on Avicenna: Life and Times.

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2. A Summa of Greek and Arabic Medicine

Avicenna did not set out to discover new diseases or new drugs. His aim was order. He took the medicine of Galen, the second-century Greek physician whose writings dominated medicine for more than a thousand years, and fitted it into the framework of Aristotle’s natural philosophy, so that every claim about the body, disease and medicine had a place in one coherent system. The French scholar A.-M. Goichon, quoted in the Encyclopaedia Iranica, called the result “the clear and ordered ‘summa’ of all the medical knowledge of Ibn Sīnā’s time.”

The works that came before it

The Canon was not the first great medical encyclopedia written in Arabic. Two Persian physicians had already produced large systematic works. Abū Bakr al-Rāzī (known in Latin as Rhazes, died about 925) had compiled enormous case-based medical writings, and ‘Alī ibn ‘Abbās al-Majūsī (Haly Abbas, later tenth century) wrote a comprehensive medical textbook which, according to the Iranica, “rivals the Canon in size.” Behind both stood the Arabic translations of Galen, Hippocrates and the Greek pharmacologist Dioscorides, made in Baghdad in the ninth century.

What set the Canon apart was its arrangement. General principles came first, then medicines, then diseases by organ and by whole body, then compound remedies. A reader could move from theory to practice in a straight line, and a teacher could lecture through it section by section. That clarity is one reason the book was later taken up by universities in Europe.

A book that drew commentators

Within the Arabic world the Canon soon became a book to be argued with as well as learned from. More than two dozen Arabic commentaries were written on it between the twelfth and fourteenth centuries. The historian Nahyan Fancy, studying commentaries by Fakhr al-Dīn al-Rāzī (died 1210) and Ibn al-Nafīs (died 1288), shows that these writers tested and questioned the Canon’s claims rather than simply repeating them. The historian Michael Stolberg has argued that in Latin Europe, too, the book’s popularity may have owed as much to the room it gave academic commentators as to its systematic form.

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3. The Five Books at a Glance

The Canon is divided into five books (in Arabic, kutub), each further divided into sections the Latin translators called fens, treatises and chapters. In outline, following the Encyclopaedia Iranica and the standard descriptions:

  1. Book 1, the Kulliyyāt (general principles). The elements, humours and temperaments; anatomy and physiology; the causes and symptoms of disease; the preservation of health through regimen and diet; and the general principles of treatment.
  2. Book 2, the materia medica. First a part on the general rules for drugs and what Avicenna called the science of the powers of medicines — including his chapter on learning a drug’s strength by experiment — and then an alphabetical list of about 800 simple drugs.
  3. Book 3, diseases of the parts. Disorders arranged organ by organ, from the head down to the feet, each with its causes, signs and treatment.
  4. Book 4, diseases of the whole body. Fevers, poisons, swellings, wounds and fractures, along with hygiene and cosmetics — conditions not confined to one organ.
  5. Book 5, the formulary. About 650 compound drugs: theriacs, electuaries, potions, syrups and other mixtures.

Two of the five books, then, are wholly about medicines, and the remaining three refer to them constantly. This is why historians of pharmacology treat the Canon as a pharmacological work as much as a medical one. In the European universities that adopted it, the parts most often made compulsory were the physiology in the first section of Book 1 and the fevers of Book 4; Book 2 was read in some universities alongside other Arabic pharmaceutical texts. That later history is followed on Opium, Saffron and the Long Life of the Canon.

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4. Elements, Humours and Temperaments

Every drug in the Canon makes sense only inside the theory that opens Book 1. It is the theory Avicenna inherited from Hippocrates and Galen, and it ruled learned medicine in the Islamic world and in Europe until the early modern period.

Four elements and four qualities

In this scheme all matter is made of four elements — earth, water, air and fire — and each element carries a pair of the four primary qualities: hot or cold, wet or dry. Fire is hot and dry, water cold and wet, air hot and wet, earth cold and dry. Anything made of mixed elements, from a human body to a seed of pepper, therefore has its own balance of the four qualities.

Four humours

The body was understood to contain four humours, or fluids: blood, phlegm, yellow bile and black bile. Each matched a pair of qualities, and health meant that the humours were present in the proper amount and proportion for that person. Disease followed when one humour grew excessive, deficient or corrupted, or when it collected where it did not belong. Melancholy, for instance, was linked to an excess of black bile; the biographies record that Avicenna treated the amir Majd al-Dawla at Ray for a melancholic illness of this kind.

Temperament

The resulting balance of qualities in a body or an organ was its temperament (Arabic mizāj). Temperament varied with age, sex, region, season and individual constitution, so the same disease could need different handling in a child and in an old man, or in a hot country and a cold one. Galenic physicians also spoke of an “innate heat” that sustained life; how the Latin Canon handled this doctrine of calor innatus is the subject of a 1993 study by Stolberg.

Why it mattered for drugs

A medicine, in this theory, acted chiefly through its own qualities. A drug judged hot and dry was used against a disease judged cold and wet, and the strength of a quality was graded in degrees. The historian Danielle Jacquart describes Arabic pharmacology from the ninth to the thirteenth century as built on Galen and Dioscorides, with two strands running side by side: the grading of drugs by degrees of their primary qualities, and the idea that some drugs act by a “specific property” of their whole substance that the four qualities cannot explain. The Canon carries both strands, as the next sections show.

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5. Regimen and Diet Before Drugs

For a book so rich in medicines, the Canon is notably reluctant to reach for them first. In the part of Book 1 on preserving health and on treatment, Avicenna puts regimen — the ordering of daily life — and diet ahead of drugs, and turns to medicines, in the summary given by the Encyclopaedia Iranica, “only when these fail.”

Regimen in this tradition covered what Galenic writers grouped as the non-natural factors of health: the air a person breathes, food and drink, sleep and waking, exercise and rest, the retention and evacuation of bodily wastes, and the passions of the soul. A 2012 review by Saffari and Pakpour describes the Canon’s view that the purpose of medicine is both to preserve health and to restore it, and highlights what it says about healthy water and air — topics that a modern reader would place under public health and sanitation.

Food itself sat on a scale with medicine. Many items in the Book 2 list — fruits, grains, spices, honey, milk — were foods as well as drugs, and their qualities were described in the same terms. A physician following the Canon would first try to correct an imbalance through what the patient ate and how the patient lived, then move to simple drugs, and only then to compounds. That ladder, from regimen to simples to compounds, is the frame within which Books 2 and 5 were meant to be read.

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6. Book 2: Eight Hundred Simple Drugs

A “simple” in medieval pharmacy is a medicine made of one substance: a root, a leaf, a resin, a mineral, an animal product. Book 2 of the Canon is devoted to them. The Encyclopaedia Iranica counts about 800 simple drugs, mostly plants but with many animal and mineral substances among them.

The two parts of Book 2

The book opens with general rules. Before any single drug is described, Avicenna discusses how the powers of medicines are known, how they act on the body, and how their strength can be judged. It is in this opening part that his chapter on knowing the potency of drugs through experimentation appears, with the seven conditions explained on Avicenna’s Seven Rules for Testing Drugs. Nasser, Tibi and Savage-Smith, who translated the chapter in 2009, give its opening idea: that experimenting leads to certain knowledge of a medicine’s potency once certain conditions are taken into account.

The second part is the list itself, arranged alphabetically by the Arabic letters. T. Siddiqi published a long study of this materia medica in 1986. Most of the substances came down from Dioscorides and Galen through the Arabic translations; others came from Persian, Indian and Arabic practice.

What the list contains

The plants range from everyday kitchen items to strong poisons. Reviews from Persian-medicine researchers that read the Canon closely pick out several that later attracted laboratory study. Mahdizadeh and colleagues (2015), reviewing its pain-relieving and anti-inflammatory substances, list opium, willow, curcuma (turmeric) and garlic among them. Hosseinzadeh and Nassiri-Asl (2013) reviewed the saffron entry and compared the uses it lists with modern work on saffron’s compounds crocin, crocetin and safranal; the comparisons are those authors’ reading, not proof that the old uses work. Heydari and colleagues (2013) studied the opium entry, which describes the drug’s pain-relieving, sleep-inducing and cough-suppressing effects, its effects on the gut and on thinking, and its depression of breathing — and in which Avicenna himself warned that opium is a poison.

Those plants and their later history are the subject of Opium, Saffron and the Long Life of the Canon. The point here is the scale and the method: hundreds of substances, every one described in the same pattern.

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7. Anatomy of a Book 2 Entry

What made Book 2 useful was the uniform shape of its entries. Following Jacquart’s account, a typical entry moves through the same headings each time:

  1. The name. The drug is identified, so a reader could match the entry to the substance in the market.
  2. Criteria of goodness. How to recognise a good specimen of the drug and tell it from a poor one.
  3. Primary qualities. Whether the drug is hot or cold, wet or dry, and to what degree — the link back to the theory of temperaments.
  4. General actions. One or more of 22 general actions a drug could have on the body.
  5. Specific properties by disease type. Its particular uses, set out on a grid of 11 types of disease.
  6. Substitutes. What could be used in its place when it could not be found.

Read in modern terms, this layout carries a surprising amount of what a pharmacopoeia still records. The criteria of goodness are an early form of quality control, aimed at the problem of impure or adulterated drugs that the first of his testing rules also addresses. The qualities and actions describe how the drug was thought to work. The disease grid works as a list of indications, and the substitutes answer a practical problem of supply that any medieval pharmacist faced.

The theory underneath was not modern. The qualities and degrees were judged within humoral theory, and the actions were described in its vocabulary, not in terms of chemical compounds or receptors. But the habit of describing every drug in the same order, under the same headings, made the information easy to compare, to teach and to copy.

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8. Book 5: The Formulary of Compound Drugs

Book 5 turns from single substances to mixtures. The Encyclopaedia Iranica counts about 650 compound drugs in it, of the kinds medieval pharmacy relied on: theriacs (complex antidote mixtures), electuaries (powders worked into honey or syrup), potions and syrups.

A formulary with a voice

Book 5 was more than a copied list. Its recipes are attributed to Arabic, Indian and Greek sources, and Avicenna often set different versions of the same remedy side by side, sometimes added his own version, and commented on how effective he judged each to be. He noted where ingredients came from and how the mixture was prepared. He favoured remedies whose value had been shown by experience, and he cautioned that a compound could act in unexpected ways, or more strongly than its separate ingredients would suggest — a recognition that mixing drugs changes what they do.

Why compounds existed at all

In humoral medicine a compound let the physician adjust the overall quality of a remedy, combine a drug with a corrective that softened its harsher effects, or treat several features of a disease at once. The ladder described above still applied: compound drugs came after regimen and simple drugs, not before them.

The oldest copy

The earliest known manuscript of Book 5 is dated 1052, about fifteen years after Avicenna’s death, and is held in the Aga Khan collection in Toronto. The full recipes, with their quantities and methods, belong to the history of pharmacy; they are not reproduced on this page.

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9. Agreeing and Arguing with Galen

Galen is the author whose name appears most often in the Canon. A 2020 study by Sadeghi and colleagues counted about 300 citations of him. Most are respectful: Avicenna praises Galen, follows him on much of anatomy and therapeutics, and builds his whole system of qualities and temperaments on Galenic foundations.

But the same study shows that he did not simply copy. Avicenna confirmed many of Galen’s views, and he also rejected some of Galen’s pharmaceutical opinions and some of his physiological ones. His larger project of fitting Galen’s medicine into Aristotle’s natural philosophy meant that Galen was an authority to be weighed, not simply transcribed.

The rules for testing drugs show the same mix. According to the historian A. C. Crombie, as cited in later accounts, the seven conditions were taken partly from Galen; what Avicenna added was their gathering into an explicit set and his insistence that the final test of a drug is its effect on the human body. Modern readers differ on how much weight to give the rules. Sajadi and colleagues (2009) called the chapter “the earliest known treatise related to clinical trials,” while Nasser, Tibi and Savage-Smith (2009) present it as rules for assessing the effects of drugs and stress the continuing relevance of the seventh rule on differences between animals and humans. The rules describe conditions for testing a drug, not a trial Avicenna is known to have run, and they include no control groups, randomisation or blinding.

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10. Poisons and Antidotes in Book 4

Poisoning had a long history in the courts where Avicenna worked, and medieval physicians were expected to know both poisons and their remedies. Book 4, on diseases of the whole body, includes a treatment of poisons alongside the fevers, wounds and fractures.

His approach to oral poisoning

A 2023 study in Archives of Toxicology by Nasiri and colleagues examined how the Canon handles poisons taken by mouth. They describe a clinical approach built on several kinds of measure: emetics to make the patient vomit, purgatives and enemas to clear the bowel, diuretics, cardiotonics (drugs believed to strengthen the heart), and nourishing foods given to protect and support the body. Whatever a modern toxicologist would make of each measure, the structure — remove the poison, protect the patient, support recovery — is recognisably clinical.

The poisons in the pharmacy

Some of the Canon’s most powerful medicines were themselves poisons. In the opium entry of Book 2 he described the drug as a potential poison, and Heydari and colleagues note that most of the effects he listed — including the slowing of breathing — were later confirmed. Aziz, Nathan and McKeever (2000) describe recipes in the Canon that used mandrake, henbane and opium to dull pain before surgery. All three plants are poisonous, and the dose that numbs pain lies close to the dose that harms; this is reported here as pharmacological history, with no preparation or use described.

Theriac

The great compound antidotes, the theriacs, link Book 4 to Book 5. Inherited from Greek medicine, where Galen wrote about them at length, theriacs were believed to protect against poisons and venoms of many kinds, and their recipes fill part of the formulary. The plants behind the Canon’s strongest drugs, and the book’s later history in Europe, are part of the story told on the Herbs, Minerals and Legacy page and on the wing’s hub, Avicenna: The Canon of Medicine and the Rules for Testing Drugs.

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Key Research Papers

  1. Sadeghi S, Ghaffari F, Heydarirad G, Alizadeh M. Galen's place in Avicenna's The Canon of Medicine: Respect, confirmation and criticism. J Integr Med. 2020;18(1):21-25. PubMed PMID: 31787564
  2. Siddiqi T. Ibn Sīnā on materia medica. Indian J Hist Sci. 1986;21(4):326-57. PubMed PMID: 11621790
  3. Jacquart D. Islamic Pharmacology in the Middle Ages: Theories and Substances. European Review. 2008;16(2):219-227. DOI: 10.1017/S1062798708000215
  4. Nasser M, Tibi A, Savage-Smith E. Ibn Sina's Canon of Medicine: 11th century rules for assessing the effects of drugs. J R Soc Med. 2009;102(2):78-80. PubMed PMID: 19208873
  5. Sajadi MM, Mansouri D, Sajadi MR. Ibn Sina and the clinical trial. Ann Intern Med. 2009;150(9):640-3. PubMed PMID: 19414844
  6. Saffari M, Pakpour AH. Avicenna's Canon of Medicine: a look at health, public health, and environmental sanitation. Arch Iran Med. 2012;15(12):785-9. PubMed PMID: 23199255
  7. Stolberg M. [Teachings of "calor innatus" in the Latin Canon medicinae of Avicenna]. Sudhoffs Arch. 1993;77(1):33-53. PubMed PMID: 8333011
  8. Fancy N. Verification and Utility in the Arabic Commentaries on the Canon of Medicine: Examples from the Works of Fakhr al-Dīn al-Rāzī (d. 1210) and Ibn al-Nafīs (d. 1288). J Hist Med Allied Sci. 2020;75(4):361-382. PubMed PMID: 32974673
  9. Heydari M, Hashempur MH, Zargaran A. Medicinal aspects of opium as described in Avicenna's Canon of Medicine. Acta Med Hist Adriat. 2013;11(1):101-12. PubMed PMID: 23883087
  10. Hosseinzadeh H, Nassiri-Asl M. Avicenna's (Ibn Sina) the Canon of Medicine and saffron (Crocus sativus): a review. Phytother Res. 2013;27(4):475-83. PubMed PMID: 22815242
  11. Mahdizadeh S, Khaleghi Ghadiri M, Gorji A. Avicenna's Canon of Medicine: a review of analgesics and anti-inflammatory substances. Avicenna J Phytomed. 2015;5(3):182-202. PubMed PMID: 26101752
  12. Aziz E, Nathan B, McKeever J. Anesthetic and analgesic practices in Avicenna's Canon of Medicine. Am J Chin Med. 2000;28(1):147-51. PubMed PMID: 10794127
  13. Nasiri E, Orimi JR, Hashemimehr M, Aghabeiglooei Z, Rezghi M, Amrollahi-Sharifabadi M. Avicenna's clinical toxicology approach and beneficial materia medica against oral poisoning. Arch Toxicol. 2023;97(4):981-989. PubMed PMID: 36862191

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