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In the history of medicine, Islamic medicine or Arabic medicine refers to medicine developed in the medieval Islamic civilization and written in Arabic, the lingua franca of the Islamic civilization. Despite these names, a significant number of scientists during this period were not Arab. Some consider the label "Arab-Islamic" as historically inaccurate, arguing that this label does not appreciate the rich diversity of Eastern scholars who have contributed to Islamic science in this era.¹ Latin translations of Arabic medical works had a significant influence on the development of modern medicine.

Overview

Islamic medicine was a genre of medical writing that was influenced by several different medical systems, including the traditional Arabian medicine of Muhammad's time, ancient Hellenistic medicine such as Unani, ancient Indian medicine such as Ayurveda, and the ancient Iranian Medicine of the Academy of Gundishapur. The works of ancient Greek and Roman physicians Hippocrates, Dioscorides, Soranus, Celsus and Galen had a lasting impact on Islamic medicine.²³⁴

Foundations

The first Muslim physician is believed to have been Muhammad himself, as a significant number of hadiths concerning medicine are attributed to him. Several Sahaba are said to have been successfully treated of certain diseases by following the medical advice of Muhammad. The three methods of healing known to have been mentioned by him were honey, fire cupping, and cauterization, though he was generally opposed to the use of cauterization unless it "suits the ailment." According to Ibn Hajar al-Asqalani, Muhammad disliked this method due to it causing "pain and menace to a patient" since there was no anasthesia in his time.⁵ Muhammad also appears to have been the first to suggest the contagious nature of leprosy, mange and sexually transmitted disease;⁶ and that there is always a cause and a cure for every disease,⁵⁷ according to several hadiths in the Sahih al-Bukhari, Sunan Abi Dawood and Al-Muwatta attributed to Muhammad, such as:

"There is no disease that Allah has created, except that He also has created its treatment."⁸

"Make use of medical treatment, for Allah has not made a disease without appointing a remedy for it, with the exception of one disease, namely old age."⁹

"Allah has sent down both the disease and the cure, and He has appointed a cure for every disease, so treat yourselves medically."¹⁰

"The one who sent down the disease sent down the remedy."¹¹

"For every disease, Allah has given a cure."⁷

The belief that there is a cure for every disease encouraged early Muslims to engage in biomedical research and seek out a cure for every disease known to them.⁷ Many early authors of Islamic medicine were usually clerics rather than physicians, and were known to have advocated the traditional medical practices of prophet Muhammad's time, such as those mentioned in the Qur'an and Hadith. For instance, therapy did not require a patient to undergo any surgical procedures at the time.

From the 9th century, Hunayn ibn Ishaq translated a number of Galen's works into the Arabic language, followed by translations of the Sushruta Samhita, Charaka Samhita, and Middle Persian works from Gundishapur. Muslim physicians soon began making many of their own significant advances and contributions to medicine, including the fields of allergology, anatomy, bacteriology, botany, dentistry, embryology, environmentalism, etiology, immunology, microbiology, obstetrics, ophthalmology, pathology, pediatrics, perinatology, physiology, psychiatry, psychology, pulsology and sphygmology, surgery, therapy, urology, zoology, and the pharmaceutical sciences such as pharmacy and pharmacology, among others.

Medicine was a central part of medieval Islamic culture. Responding to circumstances of time and place, Islamic physicians and scholars developed a large and complex medical literature exploring and synthesizing the theory and practice of medicine.¹² Islamic medicine was initially built on tradition, chiefly the theoretical and practical knowledge developed in Arabia, Persia, Greece, Rome, and India. Galen and Hippocrates were pre-eminent authorities, as well as the Indian physicians Sushruta and Charaka, and the Hellenistic scholars in Alexandria. Islamic scholars translated their voluminous writings from Greek and Sanskrit into Arabic and then produced new medical knowledge based on those texts.¹³ In order to make the Greek and Indian traditions more accessible, understandable, and teachable, Islamic scholars ordered and made more systematic the vast and sometimes inconsistent Greco-Roman and Indian medical knowledge by writing encyclopedias and summaries.¹² It was through Arabic translations that the West learned of Hellenic medicine, including the works of Galen and Hippocrates. Of equal if not of greater influence in Western Europe were systematic and comprehensive works such as Avicenna's The Canon of Medicine, which were translated into Latin and then disseminated in manuscript and printed form throughout Europe. During the fifteenth and sixteenth centuries alone, The Canon of Medicine was published more than thirty-five times.¹²

Hospitals and Universities

Main article: Bimaristan

Muslim physicians set up the earliest dedicated hospitals in the modern sense, known as Bimaristans, which were establishments where the ill were welcomed and cared for by qualified staff, and which were clearly distinguished from the ancient healing temples, sleep temples, hospices, assylums, lazarets and leper-houses which were more concerned with isolating the sick and the mad from society "rather than to offer them any way to a true cure."¹⁴ These contrasted with hospitals in Christian Europe which were more concerned with prayer. The Bimaristan hospitals later functioned as the first public hospitals,¹⁵ psychiatric hospitals¹⁶ and diploma-granting medical universities.¹⁷

In the medieval Islamic world, hospitals were built in all major cities; in Cairo for example, the Qalawun Hospital could care for 8,000 patients, and a staff that included physicians, pharmacists, and nurses. One could also access a dispensary, and research facility that led to advances, which included the discovery of the contagious nature of diseases, and research into optics and the mechanisms of the eye. Muslim doctors were removing cataracts with hollow needles over 1000 years before Western physicians dared attempt such a task. Hospitals were built not only for the physically sick, but for the mentally sick also. One of the first ever psychiatric hospitals that cared for the mentally ill was built in Cairo. Hospitals later spread to Europe during the Crusades, inspired by the hospitals in the Middle East. The first hospital in Paris, Les Quinze-vingts, was founded by Louis IX after his return from the Crusade between 1254-1260.¹⁸

Hospitals in the Islamic world featured competency tests for doctors, drug purity regulations, nurses and interns, and advanced surgical procedures.¹⁹ Hospitals were also created with separate wards for specific illnesses, so that people with contagious diseases could be kept away from other patients.²⁰

One of the features in medieval Muslim hospitals that distinguished them from their contemporaries and predecessors was their significantly higher standards of medical ethics. Hospitals in the Islamic world treated patients of all religions, ethnicities, and backgrounds, while the hospitals themselves often employed staff from Christian, Jewish and other minority backgrounds. Muslim doctors and physicians were expected to have obligations towards their patients, regardless of their wealth or backgrounds. The ethical standards of Muslim physicians was first laid down in the 9th century by Ishaq bin Ali Rahawi, who wrote the Adab al-Tabib (Conduct of a Physician), the first treatise dedicated to medical ethics. He regarded physicians as "guardians of souls and bodies", and wrote twenty chapters on various topics related to medical ethics.²¹

Another unique feature of medieval Muslim hospitals was the role of female staff, who were rarely employed in ancient and medieval healing temples elsewhere in the world. Medieval Muslim hospitals commonly employed female nurses, including nurses from as far as Sudan, a sign of great breakthrough. Muslim hospitals were also the first to employ female physicians, the most famous being two female physicians from the Banu Zuhr family who served the Almohad ruler Abu Yusuf Ya'qub al-Mansur in the 12th century.²² Later in the 15th century, female surgeons were illustrated for the first time in Şerafeddin Sabuncuoğlu's Cerrahiyyetu'l-Haniyye (Imperial Surgery).²³

Encyclopedias

The first encyclopedia of medicine in Arabic was Ali ibn Sahl Rabban al-Tabari's Firdous al-Hikmah ("Paradise of Wisdom"), written in seven parts, c. 860. It was the first to deal with pediatrics and child development, as well as psychology and psychotherapy. In the fields of medicine and psychotherapy, the work was primarily influenced by Islamic thought and ancient Indian physicians such as Sushruta and Charaka. Unlike earlier physicians, however, al-Tabari emphasized strong ties between psychology and medicine, and the need of psychotherapy and counseling in the therapeutic treatment of patients.²⁴

Muhammad ibn Zakarīya Rāzi (Rhazes) wrote the Comprehensive Book of Medicine in the 9th century. The Large Comprehensive was the most sought after of all his compositions, in which Rhazes recorded clinical cases of his own experience and provided very useful recordings of various diseases. The Comprehensive Book of Medicine, with its introduction of measles and smallpox, was very influential in Europe.

Ali ibn Abbas al-Majusi (Haly Abbas)'s Kitab Kamil as-sina'a at-tibbiyya ("Complete Book of the Medical Art"), c. 980, became better known as the Kitab al-Maliki ("Royal Book", Latin: Liber regalis) in honour of its royal patron 'Adud al-Dawla. In twenty sections, ten of theory and ten of practice, it was more systematic and concise than Razi's Hawi, but more practical than Avicenna's Canon, by which it was superseded. With many interpolations and substitutions, it served as the basis for the Pantegni (c. 1087) of Constantinus Africanus, the founding text of the Schola Medica Salernitana in Salerno.²⁵

Abu al-Qasim al-Zahrawi (Abulcasis), regarded as the father of modern surgery,²⁶ contributed greatly to the discipline of medical surgery with his Kitab al-Tasrif ("Book of Concessions"), a 30-volume medical encyclopedia published in 1000, which was later translated to Latin and used in European medical schools for centuries. He invented numerous surgical instruments and described them in his al-Tasrif.

Avicenna (Ibn Sina), a Hanbali and Mu'tazili philosopher and doctor in the early 11th century, was another influential figure. He is regarded as the father of modern medicine,²⁷ and one of the greatest thinkers and medical scholars in history. His medical encyclopedia, The Canon of Medicine (c. 1020), remained a standard textbook in Europe for centuries, up until the renewal of the Muslim tradition of scientific medicine. He also wrote The Book of Healing (actually a more general encyclopedia of science and philosophy), which became another popular textbook in Europe. Among other things, Avicenna's contributions to medicine include the introduction of systematic experimentation and quantification into the study of physiology,²⁸ the discovery of the contagious nature of infectious diseases, the introduction of quarantine to limit the spread of contagious diseases, the introduction of experimental medicine,²⁹ evidence-based medicine, clinical trials,³⁰ randomized controlled trials,³¹³² efficacy tests,³³³⁴ clinical pharmacology,³⁵ risk factor analysis, and the idea of a syndrome in the diagnosis of specific diseases,³⁶ the first descriptions on bacteria and viral organisms,³⁷ the distinction of mediastinitis from pleurisy, the contagious nature of phthisis and tuberculosis, the distribution of diseases by water and soil, and the first careful descriptions of skin troubles, sexually transmitted diseases, perversions, and nervous ailments,¹⁸ as well the use of ice to treat fevers, and the separation of medicine from pharmacology, which was important to the development of the pharmaceutical sciences.³⁸

Abū Rayhān al-Bīrūnī's Kitab-al-Saidana was an extensive medical encyclopedia which synthesized Islamic medicine with Indian medicine. His medical investigations included one of the earliest descriptions on Siamese twins.³⁹ Ibn Al-Thahabi (d. 1033) was famous for writing the first known alphabetical encyclopedia of medicine.

Ibn al-Nafis (1213-1288) wrote Al-Shamil fi al-Tibb (The Comprehensive Book on Medicine), a voluminous medical encyclopedia that was originally planned to comprise 300 volumes, but he was only able to complete 80 volumes as a result of his death in 1288. However, even in its incomplete state, the book is one of the largest known medical encyclopedias in history, though only a small portion of The Comprehensive Book on Medicine has survived. During his lifetime, The Comprehensive Book on Medicine had eventually replaced Ibn Sina's The Canon of Medicine as a medical authority in the medieval Islamic world. Arabic biographers from the 13th onwards considered Ibn al-Nafis the greatest physician in history, some referring to him as "the second Ibn Sina", and others considering him even greater than Ibn Sina.⁴⁰

The last major medical encyclopedia from the Islamic world was Şerafeddin Sabuncuoğlu's surgical atlas, Cerrahiyyetu'l-Haniyye (Imperial Surgery). Though his work was mostly based on Abu al-Qasim al-Zahrawi's Al-Tasrif, he also introduced many innovations of his own.

Legacy

George Sarton, the father of the history of science, wrote in the Introduction to the History of Science:¹⁸

"Through their medical investigations they not merely widened the horizons of medicine, but enlarged humanistic concepts generally. [...] Thus it can hardly have been accidental that those researches should have led them that were inevitably beyond the reach of Greek masters. If it is regarded as symbolic that the most spectacular achievement of the mid-twentieth century is atomic fission and the nuclear bomb, likewise it would not seem fortuitous that the early Muslim's medical endeavor should have led to a discovery that was quite as revolutionary though possibly more beneficent."

"A philosophy of self-centredness, under whatever disguise, would be both incomprehensible and reprehensible to the Muslim mind. That mind was incapable of viewing man, whether in health or sickness as isolated from God, from fellow men, and from the world around him. It was probably inevitable that the Muslims should have discovered that disease need not be born within the patient himself but may reach from outside, in other words, that they should have been the first to establish clearly the existence of contagion."

"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 fi-l-Tibb' 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."

"We have reason to believe that when, during the crusades, Europe at last began to establish hospitals, they were inspired by the Arabs of near East.... The first hospital in Paris, Les Quinze-vingt, was founded by Louis IX after his return from the crusade 1254-1260."

Scientific method

Like in other fields of Islamic science, Muslim physicians and doctors developed the first scientific methods for the field of medicine. This included the introduction of mathematization, quantification, experimentation, experimental medicine,²⁹ evidence-based medicine, clinical trials,⁴¹ dissection, animal testing,³⁸ human experimentation and postmortem autopsy by Muslim physicians, whilst hospitals in the Islamic world featured the first drug tests, drug purity regulations, and competency tests for doctors.¹⁹

Mathematization

In the 9th century, al-Kindi (Alkindus), in De Gradibus, demonstrated the application of mathematics and quantification to medicine, particularly in the field of pharmacology. This includes the development of a mathematical scale to quantify the strength of drugs, and a system that would allow a doctor to determine in advance the most critical days of a patient's illness, based on the phases of the Moon.⁴²

Experimental method

In the 10th century, Razi (Rhazes) introduced controlled experiment and clinical observation into the field of medicine, and rejected several Galenic medical theories unverified by experimentation.⁴¹ The earliest known medical experiment was carried out by Razi in order to find the most hygienic place to build a hospital. He hung pieces of meat in places throughout 10th century Baghdad and observed where the meat decomposed least quickly, and that was where he built the hospital. In his Comprehensive Book of Medicine, Razi recorded clinical cases of his own experience and provided very useful recordings of various diseases. In his Doubts about Galen, Razi was also the first to prove both Galen's theory of humorism and Aristotle's theory of classical elements false using experimentation.⁴³ He also introduced urinalysis and stool tests.⁴⁴

Avicenna, considered the father of modern medicine, introduced experimental medicine and systematic experimentation and quantification in physiology, discovered the contagious nature of diseases, and described many medical treatments, including anesthetics and medical and therapeutic drugs, in The Canon of Medicine.

Avicenna (Ibn Sina) is considered the father of modern medicine,²⁷ for his introduction of systematic experimentation and quantification into the study of physiology,²⁸ the introduction of experimental medicine,²⁹ clinical trials,³⁰ risk factor analysis, and the idea of a syndrome in the diagnosis of specific diseases,³⁶ in his medical encyclopedia, The Canon of Medicine (c. 1025), which was also the first book dealing with evidence-based medicine, randomized controlled trials,³¹³² and efficacy tests.³³³⁴

According to Toby Huff and A. C. Crombie, the Canon contained "a set of 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."⁴¹ Avicenna's emphasis on tested medicines laid the foundations for an experimental approach to pharmacology.⁴⁵ 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 pharmacology³⁵ and modern clinical trials:³⁰

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."

One of the earliest physicians known to have performed human dissection and postmortem autopsy in his medical experiments was Ibn Zuhr (Avenzoar),⁴⁶ who introduced the experimental method into surgery,⁴⁷ for which he is considered the father of experimental surgery.⁴⁸ There were a number of other early practitioners of human dissection and autopsy at the time,⁴⁹ including Ibn Tufail,⁵⁰ Saladin's physicians al-Shayzari⁴⁹ and Ibn Jumay, Abd-el-latif,⁵¹ and Ibn al-Nafis.⁵²

The experimental method was introduced into botany, materia medica and the agricultural sciences in the 13th century by the Andalusian-Arab botanist Abu al-Abbas al-Nabati, the teacher of Ibn al-Baitar. Al-Nabati introduced empirical techniques in the testing, description and identification of numerous materia medica, and he separated unverified reports from those supported by actual tests and observations.⁴¹

Peer review

The first documented description of a peer review process is found in the Ethics of the Physician written by Ishaq bin Ali al-Rahwi (854–931) of al-Raha, Syria, who describes the first medical peer review process. His work, as well as later Arabic medical manuals, state that a visiting physician must always make duplicate notes of a patient's condition on every visit. When the patient was cured or had died, the notes of the physician were examined by a local medical council of other physicians, who would review the practising physician's notes to decide whether his/her performance have met the required standards of medical care. If their reviews were negative, the practicing physician could face a lawsuit from a maltreated patient.⁵³

Anatomy and Physiology

In anatomy and physiology, the first physician to refute Galen's theory of humorism was Muhammad ibn Zakarīya Rāzi (Rhazes) in his Doubts about Galen in the 10th century. He criticized Galen's theory that the body possessed four separate "humors" (liquid substances), whose balance are the key to health and a natural body-temperature. Razi was the first to prove this theory wrong using an experiment. He carried out an experiment which would upset this system by inserting a liquid with a different temperature into the body resulting in an increase or decrease of bodily heat, which resembled the temperature of that particular fluid. Razi noted particularly that a warm drink would heat up the body to a degree much higher than its own natural temperature, thus the drink would trigger a response from the body, rather than transferring only its own warmth or coldness to it. This line of criticism was the first comprehensive experimental refutation of Galen's theory of humours and Aristotle's theory of the four classical elements on which it was grounded. Razi's own chemical experiments suggested other qualities of matter, such as "oiliness" and "sulfurousness", or inflammability and salinity, which were not readily explained by the traditional fire, water, earth and air division of elements.⁴³

Experimental anatomy and physiology

The contributions of Avicenna to physiology include the introduction of systematic experimentation and quantification into the study of physiology in The Canon of Medicine (c. 1020).²⁸ The contributions of Ibn al-Haytham (Alhacen) to anatomy and physiology include his correct explanation of the process of sight and visual perception for the first time in his Book of Optics, published in 1021.³⁸ Other innovations introduced by Muslim physicians to the field of physiology by this time include the use of animal testing³⁸ and human dissection.⁴⁹

Ibn Zuhr (Avenzoar) (1091-1161) was one of the earliest physicians known to have carried out human dissection and postmortem autopsy. He proved that the skin disease scabies was caused by a parasite, a discovery which upset the theory of humorism supported by Hippocrates and Galen. The removal of the parasite from the patient's body did not involve purging, bleeding, or any other traditional treatments associated with the four humours.⁴⁶

In the 12th century, Saladin's physicians al-Shayzari⁴⁹ and Ibn Jumay were also among the earliest to undertake human dissection, and they made explicit appeals for other physicians to do so as well. During a famine in Egypt in 1200, Abd-el-latif observed and examined a large number of skeletons, and he discovered that Galen was incorrect regarding the formation of the bones of the lower jaw and sacrum.⁵¹

The opening page of a medical work by Ibn al-Nafis, the father of the circulatory physiology. This is probably a copy made in India during the 17th or 18th centuries.

Circulatory anatomy and physiology

Ibn al-Nafis, the father of circulatory physiology,⁵⁴ was another early proponent of human dissection.⁵² In 1242, he was the first to describe the pulmonary circulation,⁵⁵ coronary circulation,⁵⁶ and capillary circulation,⁵⁷ which form the basis of the circulatory system, for which he is considered the one of the greatest physiologists in history.⁵⁸ The first European descriptions of the pulmonary circulation came several centuries later, by Michael Servetus in 1553 and William Harvey in 1628. Ibn al-Nafis also described the earliest concept of metabolism,⁵⁹ and developed new Nafisian systems of anatomy, physiology and psychology to replace the Avicennian and Galenic doctrines, while discrediting many of their erroneous theories on the four humours, pulsation,⁶⁰ bones, muscles, intestines, sensory organs, bilious canals, esophagus, stomach, and the anatomy of almost every other part of the human body.⁵²

The Arab physician Ibn al-Lubudi (1210-1267), also from Damascus, wrote the Collection of discussions relative to fifty psychological and medical questions, in which he rejects the theory of four humours supported by Galen and Hippocrates, discovers that the body and its preservation depend exclusively upon blood, rejects Galen's idea that women can produce sperm, and discovers that the movement of arteries are not dependent upon the movement of the heart, that the heart is the first organ to form in a fetus' body (rather than the brain as claimed by Hippocrates), and that the bones forming the skull can grow into tumors. He also advises that in cases of extreme fever, a patient should not be released from hospital.⁶¹

In the 15th century, the Tashrih al-badan (Anatomy of the body) written by Mansur ibn Ilyas contained comprehensive diagrams of the body's structural, nervous and circulatory systems.⁶²

Pulsology and sphygmology

Muslim physicians were pioneers in pulsology and sphygmology. In ancient times, Galen as well as Chinese physicians erroneously believed that there was a unique type of pulse for every organ of the body and for every disease.⁶³ Galen also erroneously believed that "every part of an artery pulsates simultaneously" and that the motion of the pulse was due to natural motions (the arteries expanding and contracting naturally) as opposed to forced motions (the heart causing the arteries to either expand or contract).⁶⁴ The first correct explanations of pulsation were given by Muslim physicians.

Avicenna was a pioneer of sphygmology after he refined Galen's theory of the pulse and discovered the following in The Canon of Medicine:⁶³

"Every beat of the pulse comprises two movements and two pauses. Thus, expansion : pause : contraction : pause. [...] The pulse is a movement in the heart and arteries ... which takes the form of alternate expansion and contraction."

Avicenna also pioneered the modern approach of examining the pulse through the examination of the wrist, which is still practiced in modern times. His reasons for choosing the wrist as the ideal location is due to it being easily available and the patient not needing to be distressed at the exposure of his/her body. The Latin translation of his Canon also laid the foundations for the later invention of the sphygmograph.⁶⁵

Ibn al-Nafis, in his Commentary on Anatomy in Avicenna's Canon, completely rejected the Galenic theory of pulsation after his discovery of the pulmonary circulation. He developed his own Nafisian theory of pulsation after discovering that pulsation is a result of both natural and forced motions, and that the "forced motion must be the contraction of the arteries caused by the expansion of the heart, and the natural motion must be the expansion of the arteries." He notes that the "arteries and the heart do not expand and contract at the same time, but rather the one contracts while the other expands" and vice versa. He also recognized that the purpose of the pulse is to help disperse the blood from the heart to the rest of the body. Ibn al-Nafis briefly summarizes his new theory of pulsation:⁶⁴

"The primary purpose of the expansion and contraction of the heart is to absorb the cool air and expel the wastes of the spirit and the warm air; however, the ventricle of the heart is wide. Moreover, when it expands it is not possible for it to absorb air until it is full, for that would then ruin the temperament of the spirit, its substance and texture, as well as the temperament of the heart. Thus, the heart is necessarily forced to complete its fill by absorbing the spirit."

Epidemiology, Etiology, Pathology

In etiology and epidemiology, Muslim physicians were responsible for the discovery of infectious disease and the immune system, advances in pathology, and early hypotheses related to bacteriology and microbiology.³⁸ Their discovery of contagious disease in particular is considered revolutionary and is one of the most important discoveries in medicine.¹⁸ The earliest ideas on contagion can be traced back to several hadiths attributed to Muhammad in the 7th century, who is said to have understood the contagious nature of leprosy, mange, and sexually transmitted disease.⁶ These early ideas on contagion arose from the generally sympathetic attitude of Muslim physicians towards lepers (who were often seen in a negative light in other ancient and medieval societies) which can be traced back through hadiths attributed to Muhammad and to the following advice given in the Qur'an:⁶⁶

"There is no fault in the blind, and there is no fault in the lame, and there is no fault in the sick."

This eventually led to the theory of contagious disease, which was fully understood by Avicenna in the 11th century. By then, the pathology of contagion had been fully understood, and as a result, hospitals were created with separate wards for specific illnesses, so that people with contagious diseases could be kept away from other patients who do not have any contagious diseases.²⁰ In The Canon of Medicine (1020), Avicenna discovered the contagious nature of infectious diseases such as phthisis and tuberculosis, the distribution of diseases by water and soil, and fully understood the contagious nature of sexually transmitted diseases.¹⁸ In epidemiology, he introduced the method of quarantine as a means of limiting the spread of contagious diseases,³⁰ and introduced the method of risk factor analysis and the idea of a syndrome in the diagnosis of specific diseases.³⁶

In order to find the most hygienic place to build a hospital, Muhammad ibn Zakariya ar-Razi (Rhazes) carried out an experiment where he hung pieces of meat in places throughout 10th century Baghdad and observed where the meat decomposed least quickly. Razi also wrote the Comprehensive Book of Medicine in the 9th century. The Large Comprehensive was the most sought after of all his compositions, in which Razi recorded clinical cases of his own experience and provided very useful recordings of various diseases, as well as the discovery of measles and smallpox. The Large Comprehensive also criticized the views of Galen, after Razi had observed many clinical cases which did not follow Galen's descriptions of fevers. For example, he stated that Galen's descriptions of urinary ailments were inaccurate as he had only seen three cases, while Razi had studied hundreds of such cases in hospitals of Baghdad and Rayy.⁶⁷ Chickenpox was also first indentified by Razi, who clearly distinguished it from smallpox and measles.⁶⁸ The Comprehensive Book of Medicine, especially with its introduction of measles, smallpox and chickenpox, was very influential in Europe.

Ibn Zuhr (Avenzoar) was the first physician to provide a real scientific etiology for the inflammatory diseases of the ear, and the first to clearly discuss the causes of stridor.⁶⁹ He also gave the first accurate descriptions on neurological diseases, including meningitis, intracranial thrombophlebitis, and mediastinal germ cell tumors. Averroes suggested the existence of Parkinson's disease and attributed photoreceptor properties to the retina. Maimonides wrote about neuropsychiatric disorders and described rabies and belladonna intoxication.²⁶

Allergology and immunology

The study of allergology and immunology originate from the Islamic world.³⁸ Muhammad ibn Zakarīya Rāzi (Rhazes) was responsible for discovering "allergic asthma", and was the first physician known to have written articles on allergy and the immune system. In the Sense of Smelling, he explains the occurrence of rhinitis after smelling a rose during the Spring. In the Article on the Reason Why Abou Zayd Balkhi Suffers from Rhinitis When Smelling Roses in Spring, he dicusses seasonal rhinitis, which is the same as allergic asthma or hay fever. Al-Razi was the first to realize that fever is a natural defense mechanism, the body's way of fighting disease.

The distinction between smallpox and measles also dates back to al-Razi. The medical procedure of inoculation was practiced in the medieval Islamic world in order to treat smallpox. This was later followed by the first smallpox vaccine in the form of cowpox, invented in Turkey in the early 18th century.⁷⁰

Hematology and heredity

In hematology, Abu al-Qasim al-Zahrawi (Abulcasis) wrote the first description on haemophilia, a hereditary genetic disorder, in his Al-Tasrif, in which he wrote of an Andalusian family whose males died of bleeding after minor injuries.⁷¹

Microorganisms

Muslim physicians speculated on the existence of bacteria and microorganisms, though these early theories were not proven or observed until the 17th century, when investigations into microbiology were only made possible with the invention of the microscope. These early ideas did, however, influence Girolamo Fracastoro.

Avicenna hypothesized that bodily secretion is contaminated by foul foreign earthly bodies before being infected.¹⁶³⁷

When the Black Death bubonic plague reached al-Andalus in the 14th century, Ibn Khatima hypothesized that infectious diseases are caused by small "minute bodies" which enter the human body and cause disease. Another 14th century Andalusian physician, Ibn al-Khatib (1313-1374), wrote a treatise called On the Plague, in which he stated:¹⁶

"The existence of contagion is established by experience, investigation, the evidence of the senses and trustworthy reports. These facts constitute a sound argument. The fact of infection becomes clear to the investigator who notices how he who establishes contact with the aftlicted gets the disease, whereas he who is not in contact remains safe, and how transmission is affected through garments, vessels and earrings."

Parasitology

In parasitology, Ibn Zuhr, through his dissections, was able to prove that the skin disease scabies was caused by a parasite, a discovery which upset the theory of humorism supported by Hippocrates, Galen and Avicenna. The removal of the parasite from the patient's body did not involve purging, bleeding, or any other traditional treatments associated with the four humours.⁴⁶

Dentistry

Dental surgery

Muslim dentists were pioneers in dentistry, particularly dental surgery and dental restoration. The earliest medical text to deal with dental surgery in detail was the Al-Tasrif by Abulcasis. He gave detailed methods for the successful replantation of dislodged teeth.⁷²

Dental restoration

Another 10th century Arab dentist, Abu Gaafar Amed ibn Ibrahim ibn abi Halid al-Gazzar, from North Africa, described methods of dental restoration in his Kitab Zad al-Musafir wa qut al-Hadir (Provision for the traveler and nutrition for the sedentary), which was later translated into Latin as Viaticum by Constantine the African in Salerno. He provided the earliest treatment for dental caries:⁷³

"With caries purging must take place first, and then the teeth can be filled with gallnut, dyer’s, buckthorn, terbinth resine, cedar resine, myrrh, pellitory and honey, or fumigated with colocynthis root."

Al-Gazzar also recommended arsenic compound in his prescription for holes in the teeth, as well as against dental caries, loosening, and relaxing of the nerves as a result of too many fluids.⁷⁴

Avicenna dedicated many chapters of The Canon of Medicine to dentistry, particularly dental restoration. Influenced by al-Gazzar, he provided his own treatment for dental caries, stating that carious teeth should be filled with cypress, grass, mastix, myrrh, or styrax, among others, with gallnut, yellow sulfur, pepper, camphor, and with drugs for pain relief, like arsenic or wolf’s milk. He further stated that arsenic boiled in oil should be dripped into the carious defect.⁷⁴

Both Avicenna and al-Gazzar, however, believed that dental caries were caused by "tooth worms" like what the ancients believed. This was proven false in 1200 by another Muslim physician named Gaubari in his Book of the Elite concerning the unmasking of mysteries and tearing of veils which dedicated a chapter to dentistry. He was the first to reject the idea of caries being caused by tooth worms, and he stated that tooth worms in fact do not even exist. The theory of the tooth worm was thus no longer accepted in the Islamic medical community from the 13th century onwards.⁷⁴

Obstetrics

Perinatology

Muslim physicians made many advances in obstetrics, especially perinatology. In ancient times, Greek and Hellenistic writers such as Hippocrates, Galen, Ptolemy and Paul of Aegina erroneously believed that uterine contractions were only an indication of the onset of childbirth and that the fetus would subsequently swim its way out of the womb and birth canal. In the 10th century, Ali ibn Abbas al-Majusi proved this theory false as he discovered that uterine contractions are in fact the cause of delivery of the fetus. Abu al-Qasim al-Zahrawi offered advice to midwives on childbirth and complex obstetrics in his Al-Tasrif (1000) and made a number of advances in the field. He pioneered the method of fetal craniotomy for the delivery of obstructed labour, and he introduced the required surgical instruments for this operation. Caesarean sections were described in detail by Ferdowsi in his Shahnameh (1010) and by al-Biruni in his Al-Athar al-Baliyah.⁷⁵

Embryology

Further information: The relation between Islam and science: Embryology

Embryology was discussed to some extent in early Islamic literature, including the Qur'an and the Hadith literature (see The relation between Islam and science for more details).

Ibn al-Nafis criticized previous Aristotelian, Galenic and Avicennian explanations of embryology and proceeds to develop his own theories on embryology and generation. He believed that when a male and female semen mix, and when they create a mixed matter that has an appropriate temperament to receive an animal or human soul, God issues a soul to this matter, which then develops into an embryo that grows and generates organs.⁷⁶ He further writes:

"Galen believes that each of the two semen has in it the active faculty to fashion and the passive faculty to be fashioned, however the active faculty is stronger in the male semen while the passive in the female semen. The investigators amongst the falasifa believe that the male semen only has the active faculty, while the female only has the passive faculty. ... As for our opinion on this, and God knows best, neither of the two semen has in it an active faculty to fashion."⁷⁷

He then shows that once the male semen and female semen are brought together in the womb, the female semen quenches the hot fire of the male semen through its own cool and wet nature.⁷⁸

The Arab physician Ibn al-Quff (1233-1305), a student of Ibn al-Nafis, described embryology and perinatology more accurately in his Al-Jami:

"The formation of a foam stage in the first 6 to 7 days, which in 13 to 16 days, is gradually transformed into a clot and in 28 to 30 days into a small chunk of meat. In 38 to 40 days, the head appears separate from the shoulders and limbs. The brain and heart followed by the liver are formed before other organs. The fetus takes its food from the mother in order to grow and to replenish what it discards or loses ... There are three membranes covering and protecting the fetus, of which the first connects arteries and veins with those in the mothers womb through the umbilical cord. The veins pass food for the nourishment of the fetus, while the arteries transmit air. By the end of seven months, all organs are complete ... After delivery, the baby's umbilical cord is cut at a distance of four fingers breadth from the body, and is tied with fine, soft woolen twine. The area of the cut is covered with a filament moistened in olive oil over which a styptic to prevent bleeding is sprinkled ... After delivery, the baby is nursed by his mother whose milk is the best. Then the midwife puts the baby to sleep in a darkened quiet room... Nursing the baby is performed two to three times daily. Before nursing, the mother's breast should be squeezed out two or three times to get rid of the milk near the nipple."⁷⁵

Pharmaceutical sciences

Al-Kindi was a renowned 9th century Arab doctor who wrote many books on the subject of medicine. His most important work in the field was De Gradibus, in which he demonstrated the application of mathematics to medicine, particularly in the field of pharmacology. This includes the development of a mathematical scale to quantify the strength of drugs, and a system that would allow a doctor to determine in advance the most critical days of a patient's illness, based on the phases of the Moon.⁴²

In his Comprehensive Book of Medicine, Razi (Rhazes) recorded clinical cases of his own experience and provided very useful recordings of various diseases. The Comprehensive Book of Medicine, with its introduction of measles and smallpox, was very influential in Europe. Razi also carried out an experiment in order to find the most hygienic place to build a hospital. He hung pieces of meat in places throughout 10th century Baghdad and observed where the meat decomposed least quickly, and that was where he built his hospital.

In the 10th century, Abu al-Mansur al-Muwaffak mentions for the first time some chemical facts to distinguish certain medicines.⁷⁹

Clinical pharmacology

Avicenna's contribution to pharmacology and the pharmaceutical sciences in The Canon of Medicine (1020s) include the introduction of systematic experimentation and quantification into pharmacology and the study of physiology,²⁸ the introduction of clinical pharmacology,³⁵ experimental medicine,²⁹ evidence-based medicine, clinical trials,³⁰ randomized controlled trials,³¹³² efficacy tests,³³³⁴ the experimental use and testing of drugs, a precise guide for practical experimentation in the process of discovering and proving the effectiveness of medical substances,⁴¹ and the first careful descriptions of skin troubles, sexually transmitted diseases, perversions, and nervous ailments,¹⁸ as well the use of ice to treat fevers, and the separation of medicine from pharmacology, which was important to the development of the pharmaceutical sciences.³⁸ 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 pharmacology³⁵ and modern clinical trials:³⁰

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."

Pharmacy

In the field of pharmacy, the first drugstores were opened by Muslim pharmacists in Baghdad in 754,⁸⁰ while the first apothecary shops were also founded by Muslim practitioners.⁸¹

The advances made in the Middle East by Muslim chemists in botany and chemistry led Muslim physicians to substantially develop pharmacol