Canon of Medicine

This article is about The encyclopedia compiled by Avicenna. For other uses, see Unani.

The Canon of Medicine
The Book of Healing
Hayy ibn Yaqdhan
Criticism of Avicennian philosophy
Unani medicine

The Canon of Medicine (Arabic: القانون في الطبal-Qānūn fī al-Ṭibb) is an encyclopedia of medicine in five books compiled by Persian philosopher Ibn Sīnā (Avicenna) and completed in 1025.[1] It presents a clear and organized summary of all the medical knowledge of the time. It is the most influential Galenic document of the Middle Ages[2] It served as a more concise reference in contrast to Galen's twenty volumes of medical corpus.[3] In addition to its Galenic references, Canon is full of Aristotelian undertones and direct adaptations. Originally written in the Arabic language, the book was later translated into a number of other languages, including Persian, Latin, Chinese, Hebrew, German, French, and English with lots of commentaries.[4][5] The Canon is considered one of the most famous books in the history of medicine.[6]

Canon from Latin canōn, from Ancient Greek κανών (kanón, “measuring rod, standard”), akin to κάννα (kanna, “reed”), perhaps from Semitic (compare Arabic قانون (Qānūn, “law”) Hebrew קנה (qaneh, “reed”)). also Qanun, means "law" in Arabic, Persian, Urdu and Turkish (spelled as Kanun), the Canon of Medicine remained a medical authority for centuries. It set the standards for medicine in Medieval Europe and the Islamic world, and is Avicenna's most renowned written work. Qanun was used at many medical schools—at University of Montpellier, France, as late as 1650.[7] Much of the book was also translated into Chinese as the Huihui Yaofang (Prescriptions of the Hui Nationality) by the Hui people in Yuan China.[8] The Canon was used as a medical textbook through the eighteenth century in Europe.[9] It is used in Unani (Ionian) medicine, a form of traditional medicine practiced in India. The principles of medicine described by the Canon ten centuries ago are still taught at UCLA and Yale University, among others, as part of the history of medicine.

George Sarton, the father of the history of science, wrote in the Introduction to the History of Science:

"One of the most famous exponents of Muslim universalism and an eminent figure in Islamic learning was Ibn Sina, known in the West as Avicenna (981-1037). For a thousand years he has retained his original renown as one of the greatest thinkers and medical scholars in history. His most important medical works are the Qanun (Canon) and a treatise on Cardiac drugs. The 'Qanun' is an immense encyclopedia of medicine. It contains some of the most illuminating thoughts pertaining to distinction of mediastinitis from pleurisy; contagious nature of phthisis; distribution of diseases by water and soil; careful description of skin troubles; of sexual diseases and perversions; of nervous ailments."

Influence in Western world

The Qanun was translated into Latin as Canon medicinae by Gerard of Cremona in the 12th century. Henceforth the Canon served as the chief guide to medical science in the West and is said to have influenced Leonardo da Vinci. Its encyclopaedic content, its systematic arrangement and philosophical plan soon worked its way into a position of pre-eminence in the medical literature of Europe, displacing the works of Galen and becoming the text book for medical education in the schools of Europe.[9] The text was read in the medical schools at Montpellier and Leuven as late as 1650, and Arnold C. Klebs described it as "one of the most significant intellectual phenomena of all times." In the words of Dr. William Osler, the Qanun has remained "a medical bible for a longer time than any other work".

The first three books of the Latin Canon were printed in 1472, and a complete edition appeared in 1473. In the last 30 years of the 15th century it passed through 15 Latin editions. In recent years, a partial translation into English was made.

The influential Canadian physician, Sir William Osler, described the Canon as "the most famous medical textbook ever written" noting that it remained "a medical bible for a longer time than any other work."[10] In 2006, Professor John Urquhart noted the relevance of the Canon to modern medicine, comparing it to an influential medical work of the 19th century, The Principles and Practice of Medicine (1892) by Osler himself, and concluded:

"If the year were 1900 and you were marooned and in need of a guide for practical medicine, which book would you want by your side?" My choice was Ibn Sina. A leading reason is that Ibn Sina gives an integrated view of surgery and medicine, whereas Osler largely shuns intervention. Ibn Sina, for example, tells how to judge the margin of healthy tissue to take with an amputation, a basic topic uncovered by Osler. The gap between medicine and surgery is now closing, with the advent of interventional cardiology, gastroenterology, radiology, etc. Ibn Sina correctly saw medicine and surgery as one.[11]

Mona Nasser Aida Tibi and Emilie Savage-Smith note: "The enduring respect in the 21st century for a book written a millennium earlier is testimony to Ibn Sina's achievement."[12]



The book explains the causes of health and disease. Ibn Sina believed that the human body cannot be restored to health unless the causes of both health and disease are determined. He defined medicine (tibb) as follows:

"Medicine is the science by which we learn the various states of the body; in health, when not in health; the means by which health is likely to be lost; and, when lost, is likely to be restored. In other words, it is the art whereby health is concerned and the art by which it is restored after being lost."[13]

Avicenna regarded the causes of good health and diseases to be:

  1. The Material Causes
  2. The Elements
  3. The Humors
  4. The Variability of the Tumors
  5. The Temperaments
  6. The Psychic Faculties
  7. The Vital Force
  8. The Organs
  9. The Efficient Causes
  10. The Formal Causes
  11. The Vital Faculties
  12. The Final Causes

The Qanun distinguishes mediastinitis from pleurisy and recognises the contagious nature of phthisis (tuberculosis of the lung) and the spread of disease by water and soil. It gives a scientific diagnosis of ankylostomiasis and attributes the condition to an intestinal worm. The Qanun points out the importance of dietetics, the influence of climate and environment on health, and the surgical use of oral anaesthetics.[14][verification needed] Ibn Sina advised surgeons to treat cancer in its earliest stages, ensuring the removal of all the diseased tissue.[15][verification needed] The Qanun 's materia medica considers some 800 tested drugs, with comments on their application and effectiveness.[16] He recommended the testing of a new drug on animals and humans prior to general use.

The earliest known copy of volume 5 of the Canon of Medicine dated 1052 is held in the collection of the Aga Khan and is to be housed in the Aga Khan Museum planned for Toronto, Ontario, Canada.[17]

Book 1 Part 1

Book 1 is made up of 6 Thesis' which give a general description of medicine in general, the cosmic elements that make up the cosmos and the human body, the mutual interaction of elements (temperaments), fluids of the body (humours), human anatomy, and physiology.[18]

Thesis I Definition and Scope of Medicine

Avicenna begins part one by dividing theoretical medicine and medical practice. He describes what he says are the "four causes" of illness, based on Aristotelian philosophy: The material cause, the efficient cause, the formal cause:

  1. Material Cause Avicenna says that this cause is the human subject itself, the "members or the breath" or "the humours" indirectly.
  2. Efficient Cause The efficient cause is broken up into two categories: The first is "Extrinsic", or the sources external to the human body such as air or the region we live in. The second efficient cause is the "Intrinsic", or the internal sources such as our sleep and "its opposite-the waking state", the "different periods of life", habits, and race.
  3. Formal Cause The formal cause is what Avicenna called "the constitutions ; the compositions". According to Oskar Cameron Gruner, who provides a treatise within Avicenna's Canon of Medicine, this was in agreement with Galen who believed that the formal cause of illness is based upon the individual's temperament.
  4. Final Cause The final cause is given as "the actions or functions".[19]

Thesis II The Elements or Cosmology

Avicenna's thesis on the elements of the cosmos is described by Gruner as "the foundation of the whole Canon".[20] Avicenna insists here that a physician must assume the four elements that are described by natural philosophy. This philosophy was directly adopted from Aristotelianism, which is verified when he says, "two are light, and two are heavy."[21] These "light" elements are fire and air, while the "heavy" are earth and water. Ibn Sina (Avicenna) goes on to describe each of the four elements in detail.

  1. The Earth Avicenna upholds Aristotelian philosophy by describing Earth as an element that is geocentric. He suggests that the reason for Earth's geocentricity is because of the weight it bears, but makes no further inspection.[22]
  2. The Water Water is described as being situated between Earth and Air and "cold and moist." He contrasts the wetness of water with the dryness of earth.[22]
  3. The Air The position of air between water and fire is reinforced along with air's general purpose, to "rarefy" and make things "softer".[23]
  4. The (sphere of the) Fire Along with its lofty position, fire is described as "hot and dry" and it's purpose is given by Ibn Sina as an agent of growth and maturity. He says that "all things return to it."[24]

Thesis III The Temperaments

The Canon of Medicine divides the thesis on temperaments into three subsections; a general overview, one based on members of the body, and temperaments based on age.

I The Temperaments (General description)

The temperaments are reported to be the interaction between the four different element's qualities, such as the conflict between dryness, wetness, cold, and hot. Avicenna suggests that these qualities battle between each other until an equilibrium state is reached and this state is known as the temperaments.[25]

The Canon also adopted the ancient theory of Four Temperaments and extended it to encompass "emotional aspects, mental capacity, moral attitudes, self-awareness, movements and dreams." It summarized Avicenna's own theory of four temperaments in a table presented as follows:[26]

Avicenna's four primary temperaments
Evidence Hot Cold Moist Dry
Morbid states inflammations become febrile fevers related to serious humour, rheumatism lassitude loss of vigour
Functional power deficient energy deficient digestive power difficult digestion
Subjective sensations bitter taste, excessive thirst, burning at cardia Lack of desire for fluids mucoid salivation, sleepiness insomnia, wakefulness
Physical signs high pulse rate, lassitude flaccid joints diarrhea, swollen eyelids, rough skin, acquired habit rough skin, acquired habit
Foods & medicines infrigidants beneficial calefacients beneficial moist articles harmful dry regimen harmful, humectants beneficial
Relation to weather worse in summer worse in winter bad in autumn
The Eight Varieties of Equipoise

Canon describes humans as having eight different "varieties of equipoise", or differing temperaments.[27] The temperaments fall under two categories; In relation to beings other than men and in relation to the individual himself.

A. In relation to beings other than men

i. "the equability of the temperament seen in man as compared with other creatures"
ii. the temperament of other human beings

Avicenna describes a hot versus cold / moist versus dry equilibrium between the members of the human body. The heart, for example, is hot and must be in equilibrium of other cold parts of the body such as the brain. When this equilibrium between these members are achieved, the person is considered to be in "ideal equability." [28]

iii. external factors "such as race, climate, atmosphere"

This third gauge for temperament assumes that each race has their own equilibrium. As an example he says, "The Hindus, in health, have a different equability to the Slaves, and so on." Avicenna explains that the differing climates contribute to differing temperaments among the races.[29]

iv. in relation to extreme climates

B. In relation to the individual himself

v. "as compared to another person"

Although Avicenna had listed the fifth mode "as compared to another person", he seems to contradict that statement by explaining that every individual has a temperament that is unique to themselves and unlike anyone else.[30]

vi. comparison of the individual himself
vii. comparing one member of the body with another member of the body

The Canon here makes the distinction of the members into categories of their individual "moistness", "dryness", "hotness", and "coldness".

viii. comparison of a member to itself

The Canon continues to explain the sun's position in relation to ideal temperament and the role that climate and human skin play. Organs are nowhere near ideal in temperament, but skin comes the closest. Avicenna says that the hand, especially the palm and the tip of the index finger, is the most sensitive of all and attuned to tactile contact. Medicine is described as "hot" or "cold", not based upon its actual temperature but with regard to how it relates to the temperament of the human body.[31]

The Canon then describes when temperaments are unequal, in other words, illness. Avicenna separates these into two categories, which are fairly self explainable within the context of what Ibn Sina has already defined as the temperaments.

A. Simple "intemperaments"

i. Hot temperament (hotter than normal) ii. Cold temperament (colder than normal) iii. Dry temperament (drier than usual) iv. Moist temperament (more moist than usual) [32]

B. Compound "intemperaments"

Avicenna gives a general overview of the compound intemperaments by saying that they are subdivided into 16 total intemperaments and mentions that examples are provided in the "third and fourth volumes."[33]

II The Temperament of the Several Members

Each member of the body is described to be given each its individual temperament, each with its own degree of heat and moisture. Avicenna lists members of the body in "order of degree of Heat", from hottest to coldest.[34]

  1. the breath and "the heart in which it arises"
  2. the blood; which is said to be generated from the liver
  3. the liver; "which may be looked upon as concentrated blood."
  4. the flesh
  5. the muscles
  6. the spleen
  7. the kidneys
  8. the arteries
  9. the veins
  10. the skin of the palms and soles

Then a list is given of coldest members to hottest.[34]

  1. serious humour
  2. the hairs
  3. the bones
  4. the cartilage
  5. the ligaments
  6. the tendon
  7. the membranes
  8. the nerves
  9. the spinal cord
  10. the brain
  11. the fat
  12. the oil of the body
  13. the skin

Then a list is given in order of moisture. Avicenna credits Galen with this particular list.[35]

  1. serious humour
  2. the serious humour
  3. the blood
  4. the oil
  5. the fat
  6. the brain
  7. the spinal cord
  8. the breasts and the testicles
  9. the lung
  10. the liver
  11. the spleen
  12. the kidneys
  13. the muscles
  14. the skin

Finally, a list is given in order of dryness[36]

  1. the hair
  2. the bone
  3. cartilage
  4. ligaments
  5. tendons
  6. sereous membranes
  7. arteries
  8. veins
  9. motor nerves
  10. heart
  11. sensory nerves
  12. skin

III The Temperaments Belonging to Age

The Canon divides life into four "periods" and then subdivides the first period into five separate categories.

The following table is provided for the four periods of life:[37]

Period Title Name Year of Age
I The Period of Growth Adolescence Up to 30
II The Prime of Life Period of beauty Up to 35 or 40
III Elderly life Period of decline. Senescence. Up to about 60
IV Decrepit Age Senility To the end of life

Avicenna says that the third period shows signs of decline in vigor and some decline in intellectual power. In the fourth period, both vigor and intelligence decline.

Avicenna divides the beginning stage of life in the following table, according to Oskar Cameron Gruner's edition of the Canon of Medicine:[38]

Sub-division Name Distinctive Characters
First Infancy The period before the limbs are fitted for walking
Second Babyhood The period of formation of the teeth. Walking has been learnt, but is not steady. The gums are not full of teeth.
Third Childhood The body shows strength of movement. The teeth are fully out. Pollutions have not yet appeared
Fourth Juvenility. "Puberty" The period up to the development of hair on the face and pubes. Pollutions begin.
Fifth Youth The period up to the limit of growth of the body (to the beginning of adult life). Period of athletic power.

Avicenna generalizes youth as having a "hot" temperament, but comments that there is controversy over which periods of youth are hotter. The general notion that youth are "hot" in temperament is due to youth's supposed relationship to members of the body that are hot. For example, blood was considered "hot" as was mentioned earlier, therefore youth is assumed to be hot partially due to blood being more "plentiful" and "thicker", according to Avicenna. Evidence for youth having an excess of blood is suggested by Avicenna's observation that nose bleeds are more frequent within youth. Other contributing factors are the youth's association with sperm and the consistency of their bile. Further description of youth in regards to heat and moisture is given with respect to sex, geographical location, and occupation. The Canon says, for example, that females are colder and more moist.[39]

The Humours

The Canon of Medicine is based upon the Four Humours of Hippocratic medicine, but refines in various ways. In disease pathogenesis, for example, Avicenna "added his own view of different types of spirits (or vital life essences) and souls, whose disturbances might lead to bodily diseases because of a close association between them and such master organs as the brain and heart[40] An element of such belief is apparent in the chapter of al-Lawa" (see Cardiology section), which relates "the manifestations to an interruption of vital life essence to the brain." He combined his own view with that of the Four Humours to establish a new doctrine to explain the mechanisms of various diseases in another work he wrote, Treatise on Pulse

“From mixture of the four [humors] in different weights, [God the most high] created different organs; one with more blood like muscle, one with more black bile like bone, one with more phlegm like brain, and one with more yellow bile like lung.
[God the most high] created the souls from the softness of humors; each soul has it own weight and amalgamation. The generation and nourishment of proper soul takes place in the heart; it resides in the heart and arteries, and is transmitted from the heart to the organs through the arteries. At first, it [proper soul] enters the master organs such as the brain, liver or reproductive organs; from there it goes to other organs while the nature of the soul is being modified in each [of them]. As long as [the soul] is in the heart, it is quite warm, with the nature of fire, and the softness of bile is dominant. Then, that part which goes to the brain to keep it vital and functioning, becomes colder and wetter, and in its composition the serous softness and phlegm vapor dominate. That part, which enters the liver to keep its vitality and functions, becomes softer, warmer and sensibly wet, and in its composition the softness of air and vapor of blood dominate.
In general, there are four types of proper spirit: One is brutal spirit residing in the heart and it is the origin of all spirits. Another – as physicians refer to it – is sensual spirit residing in the brain. The third – as physicians refer to it – is natural spirit residing in the liver. The fourth is generative – i.e. procreative – spirits residing in the gonads. These four spirits go-between the soul of absolute purity and the body of absolute impurity.”

What a Body Fluid is and How Many Kinds There Are

The Canon defines a humour as "that fluid, moist 'body' into which our aliment is transformed."[41] and lists the four primary types of fluids as sanguineous, serous, bilous, and atribilious. The secondary fluids are separated into "non-excrementitious" and "excrementitious".

The Four Body Fluids or Humours Proper

The sanguineous humour

Avicenna calls this humour "the most excellent of all"[42] the humours. This section describes blood and compares its healthy states with its unhealthy states. Avicenna describes healthy blood as "red in colour, has no unpleasant odour, and has a very sweet taste." Abnormality of the blood stems from a change in temperament or an unhealthy humour has polluted it.[43]

The serous humour

The serous humour is described as a sweet fluid that is cold and moist in relation to blood and bilous humours. Serous humour resembles blood and is necessary for body tissues for two reasons: to provide the tissue with nutrients as an auxiliary and to keep the bones and tissues moist.[44]

The bilous humour
The atribilious humour

Anatomy or "The Members"

In his thesis on "The Members", Avicenna explains that the humours help to make up the members of the body, gives a general description and how to repair them.
Some are "simple members" or "elementary tissue" such as bone, cartilage and tendons. Some are "compound members" such as the heart, the liver, and the brain. He also categorizes these into vital organs and auxiliary organs.[45]

General Physiology and Psychology

In the thesis on General Physiology or "The Faculties of the Body", Avicenna separates life into three different categories: Vegetable, Animal, and Human.

Book 1 part 2 general Anatomy and physiology

Writings on anatomy in the Canon are scattered throughout the text in sections regarding to illnesses related to certain body parts. The Canon included numerous discussions on anatomy and diagrams on certain body parts, including the first diagrams of the cranial sutures.[46]

Blood pressure

Avicenna dedicated a chapter of the Canon to blood pressure. He was able to discover the causes of bleeding and haemorrhage, and discovered that haemorrhage could be induced by high blood pressure because of higher levels of cholesterol in the blood. This led him to investigate methods of controlling blood pressure.[47][verification needed]


The Canon distinguished anatomy "from other aspects of medicine by its need for a different methodology." It thus stated:[48]

"As for the parts of the body and their functions, it is necessary that they be approached through observation (hiss) and dissection (tashrih), while those things that must be conjectured and demonstrated by reason are diseases and their particular causes and their symptoms and how disease can be abated and health maintained."

Neuroanatomy and neurophysiology

Avicenna discovered the cerebellar vermis—which he named "vermis"—and the caudate nucleus, which he named "tailed nucleus" or "nucleus caudatus". These terms are still used in modern neuroanatomy and neurophysiology.[47][verification needed]

The Canon was also the earliest text to note that intellectual dysfunctions were largely due to deficits in the brain's middle ventricle, and that the frontal lobe of the brain mediated common sense and reasoning.[49]


The contributions of the Canon to ophthalmology in medieval Islam include its descriptions and explanations on the physiology of eye movements, which still forms a basis of information for modern ophthalmology. He also provided useful information on the optic nerves, iris, and central and peripheral facial paralyses.[47][verification needed]

Another contribution the Canon made to ophthalmology was the suggestion that "the optic nerves did cross."[1]

Book 2 (materia medica)

The Canon described no less than 700 preparations of medications, their properties, mode of action and their indications. He devoted a whole volume to simple and compound drugs in The Canon of Medicine. It credits many of them to a variety of Arabic, Greek and Indian authors, and also includes drugs imported from China, along with many of Ibn Sina's own contributions. Using his expertise, he was often critical of the descriptions given by previous authors and revised many of their descriptions.[16][verification needed] In inhalational drug therapy, the Canon described the inhalation of essential oils from pine and eucalyptus to alleviate respiratory symptoms. Both of these compounds are still present in modern-day proprietary inhalational medicines.[50]

The Canon of Medicine deals with evidence-based medicine, experimental medicine,[51] clinical trials, randomized controlled trials,[52][53] efficacy tests,[54][55] risk factor analysis, and the idea of a syndrome in the diagnosis of specific diseases.[56]

According to A. C. Crombie, the Canon contained "a set of seven rules that laid down the conditions for the experimental use and testing of drugs" which were "a precise guide for practical experimentation" in the process of "discovering and proving the effectiveness of medical substances based in part on Galen."[51][57] The emphasis of the Canon on tested medicines laid the foundations for an experimental approach to pharmacology.[58] The Canon laid out the following rules and principles for testing the effectiveness of new drugs and medications, which still form the basis of clinical pharmacology[59] and modern clinical trials:[60]

  1. "The drug must be free from any extraneous accidental quality."
  2. "It must be used on a simple, not a composite, disease."
  3. "The drug must be tested with two contrary types of diseases, because sometimes a drug cures one disease by Its essential qualities and another by its accidental ones."
  4. "The quality of the drug must correspond to the strength of the disease. For example, there are some drugs whose heat is less than the coldness of certain diseases, so that they would have no effect on them."
  5. "The time of action must be observed, so that essence and accident are not confused."
  6. "The effect of the drug must be seen to occur constantly or in many cases, for if this did not happen, it was an accidental effect."
  7. "The experimentation must be done with the human body, for testing a drug on a lion or a horse might not prove anything about its effect on man."

The Canon lists 800 tested drugs, including plant and mineral substances, with comments on their application and effectiveness. For each one, he described their pharmaceutical actions from a range of 22 possibilities (including resolution, astringency and softening), and their specific properties according to a grid of 11 types of diseases.[16]

Inductive logic

While Ibn Sina often relied on deductive reasoning in The Book of Healing and other writings on logic in Islamic philosophy, he used a different approach in The Canon of Medicine. This text contributed to the development of inductive logic, which it used to develop the idea of a syndrome in the diagnosis of specific diseases. The Canon of Medicine was the first to describe the methods of agreement, difference and concomitant variation which are critical to inductive logic and the scientific method.[56][61][62]

Book 3 Special Pathology

Book 3 is arranged from head to toe covering the function and diseases of each organ.

Book 4 Special Diseases Involving More Than One Member

Book 4 covers diseases that affect the whole body like fevers.

Book 5 Formulary

Book 5 covers compound drugs.[63]

See also

Notes and references

External links

  • Biography of Avicenna
  • A scanned copy of "Kitab alQanun fi alTibb" (Book (of) the Canon of Medicine)