Rhazes

Abu Bakr Muhammad ibn Zakariyya al-Razi, known in the Latin West as Rhazes, was a Persian physician and philosopher who lived from approximately 854 to 925 CE in the city of Rayy, near modern Tehran. He is most famous for two things: the first clinical description in any medical literature that distinguishes smallpox from measles as separate diseases, and a book-length challenge to the authority of Galen that insisted physicians owed more to observation than to inherited doctrine. Working within the Galenic humoral framework he had inherited, al-Razi spent his career testing whether that framework’s recommendations actually worked, and writing down the results when they did not. His massive medical compendium, the Kitab al-Hawi (known in Latin as the Liber Continens), survived to become one of the most frequently cited medical texts in medieval European universities.

Early Life and Vocation

Sigerist’s Great Doctors (1933) preserves the basic biographical facts as they were transmitted through the Arabic tradition. The Latin name “Rhazes” is a transliteration of Ar-Razi, attached to him because he was born at Raj in Khorassan, north-eastern Persia. His full name in Arabic sources is Abu Bekr Mohammed ibn Zakkariya, Ar-Razi. He came to medicine relatively late: in his earlier years he studied not medicine but philosophy and music, and he was reportedly an accomplished lute-player. According to the tradition Sigerist relays, his interest in medicine was kindled through friendship with an elderly apothecary at the local hospital, whose discussions drew him into the field.(Henry E. Sigerist, 1933)

The historical conditions that made al-Razi’s career possible were the political and intellectual conditions created by the Arab conquests. Within little over a century of the Hegira, the caliphate had become a contiguous state stretching from the Pyrenees to the Indus, holding within it the most diversified populations of the late antique world bound by a common faith. Most of the regions absorbed in this expansion were regions of ancient civilisation, and the conquerors took over the relics of Greco-Roman culture wherever they went.(Henry E. Sigerist, 1933) Greek medical manuscripts were translated into Arabic primarily by way of Syriac intermediaries: the Christian scholar Hunain ibn Ishaq was especially important in the ninth century, with translation work organised at Gondeshapur on the Persian Gulf, where a Syriac medical school had long existed. Libraries were established, schools arose, and hospitals were built. The Islamic medical world also expanded the inherited Greek materia medica substantially, introducing substances unknown to ancient physicians — camphor, musk, senna, myrobalan, and sal ammoniac among them — and developing distillation techniques for essential oils and inorganic acids, along with new pharmaceutical equipment.(Pormann, 2007) Al-Razi inserted himself into this institutional structure when he turned from philosophy and music to clinical practice.(Henry E. Sigerist, 1933)

When al-Razi was summoned to Baghdad to oversee the establishment of a new hospital, the first task imposed on him was to choose the site.(Henry E. Sigerist, 1933) He hung uncooked joints of meat in various candidate locations and selected the place where putrefaction proceeded most slowly, reasoning that the air there must be most healthy.(Henry E. Sigerist, 1933) Pormann and Savage-Smith note that Islamic hospitals (bimaristans) emerged in the late eighth or early ninth century in Iraq and were funded through charitable endowments (waqf).(Pormann, 2007) From the early tenth century, prominent hospitals in Baghdad were established under caliph al-Muqtadir and his court, with al-Razi serving as a hospital director who also treated patients at home.(Pormann, 2007)

Physician and Philosopher

The most careful students of medieval Islamic medicine have consistently placed al-Razi in a category that needs some unpacking. Temkin, writing in Galenism (1973), observes that the great Arabic physicians were almost without exception also philosophers, and that “to be called ‘only a physician’ and to be denied the title of philosopher… was equivalent to being called a medical practitioner without real scientific knowledge.” Al-Razi stands alongside al-Kindi, Avicenna, Averroes, and Maimonides in this tradition of philosopher-physicians trained principally in the Aristotelian inheritance.(Temkin, 1973)

Temkin records that Galen’s philosophical authority was “from the beginning viewed with reservation where physics, logic, and metaphysical speculations were concerned,“(Temkin, 1973) and that this challenge came consistently from Arabic and Byzantine philosopher-physicians, even as his medical authority was widely accepted.(Temkin, 1973) [GAP: Specific discussion of al-Razi’s role, his acceptance of Galen’s medical system, and his empirical and philosophical challenges]

The intellectual tradition within which al-Razi stood as a philosopher-physician had a specific origin. O’Leary, in How Greek Science Passed to the Arabs (2015), identifies al-Kindi (d. c. 873) as the founder of the Arab Aristotelian school: the first figure to work systematically at the intersection of Greek philosophy and Arabic thought, and the ancestor from whom Avicenna, Averroes, and most of the great Arabic philosopher-physicians traced their intellectual lineage.(OLeary, 2015) Al-Razi lived and worked within this tradition, even as his atomism and his anti-Aristotelian physics placed him at odds with its mainstream. His philosophical heterodoxy was a deviation from within the school, not an attack from outside it.

The conditions under which scholars like al-Razi practiced illustrate the structural vulnerabilities that shaped Islamic intellectual life. O’Leary describes the ambivalent position of Arabic science throughout this period: it flourished under court patronage (caliphs and their wazirs commissioned translations, supported hospitals, and kept physicians in residence), while the scholars who produced it were often regarded with suspicion as tending toward free-thinking and heresy.(OLeary, 2015) For al-Razi, whose philosophical writings questioned the necessity of prophetic religion, this structural suspicion was not merely institutional background: it was a direct hazard. That much of his philosophical work survives only through hostile summaries by critics is a consequence of the same pattern.

His philosophical independence extended beyond medicine. Al-Razi was a thoroughgoing atomist who challenged Aristotelian physics and, according to later sources, questioned the necessity of prophetic religion: positions that made him controversial among Muslim contemporaries. Goodman, in Islamic Humanism (2003), preserves one of the more distinctive philosophical positions surviving from al-Razi: that “five eternal principles — Time, Space, Matter, Soul, and God — are preconditions of the created world,” a position Goodman characterizes as an Epicurean/Platonic formatio mundi offered against Aristotelian eternalism.[good-ih03-ch04-004] The exact nature and extent of these heterodoxies is difficult to assess because much of his philosophical writing survives only in hostile summaries by his critics.

A specific theological pressure that bore on philosopher-physicians of al-Razi’s generation was the problem of the soul as temperament. Galen had argued that the faculties of the soul follow the temperament (mixture) of the body, a position that, taken seriously, implied that the soul could not survive the body’s dissolution. Temkin notes that this teaching was theologically problematic for Jewish, Christian, and Muslim authorities alike, since it endangered the doctrine of the immortal soul.(Temkin, 1973) Al-Razi’s own preference for the body’s natural processes over revelation, combined with his materialist commitments, placed him squarely on the dangerous side of this debate. The compromises that subsequent Arabic Galenists worked out (accepting Galen’s clinical authority while bracketing his metaphysics) were in part responses to controversies that al-Razi’s generation made unavoidable.

The Five Eternal Principles

The framework that organised al-Razi’s philosophy was a cosmogony of five co-eternal principles. Goodman, in his chapter on al-Razi for Nasr and Leaman’s History of Islamic Philosophy (1996), reconstructs the argument from the surviving fragments and hostile summaries. Al-Razi had taken seriously two opposing pressures: the orthodox Muslim doctrine of creation from nothing (which raised the question of why God created when He did rather than before), and the Aristotelian doctrine of an eternal world (which collapsed into infinite regress). His response was to posit five eternal beings whose interactions framed the world: God, Soul, absolute Time, absolute Space, and Matter. In the beginning these five coexisted; God and Soul were beyond time and space, and matter was extended within them but not throughout them, leaving room for the void.(Nasr, Seyyed Hossein & Leaman, Oliver (eds.), 1996)

The cosmogony continued with an account of how the world acquired its present configuration.(Nasr, Seyyed Hossein & Leaman, Oliver (eds.), 1996) Soul, in al-Razi’s reconstruction, fell into matter through a movement that was neither compelled by physical necessity nor chosen by intellect; it was a spontaneous motion analogous to Epicurus’s clinamen, the swerve by which atoms break their parallel descent.(Nasr, Seyyed Hossein & Leaman, Oliver (eds.), 1996) God permitted the fall but did not cause it, on the reasoning that souls learn only through experience.(Nasr, Seyyed Hossein & Leaman, Oliver (eds.), 1996) He then intervened to impart intelligence to Soul so that she could recognise that matter was not her true home and begin her return to the spiritual world.(Nasr, Seyyed Hossein & Leaman, Oliver (eds.), 1996)

Al-Razi’s atomism stood at the centre of this physics. He took up the Epicurean position that ultimate constituents are physically but not geometrically indivisible, distinguishing his view sharply from the kalam atomists of his day, for whom atomism was a religious doctrine deployed to defend occasionalist theology. For al-Razi atomism was an explanatory hypothesis, defended on its merits as a way of accounting for observed change.(Nasr, Seyyed Hossein & Leaman, Oliver (eds.), 1996) The void played a particular role in his system. He argued that empty space exerts an attractive force, a doctrine Goodman characterises as a way of grounding the Epicurean swerve and connecting cosmology to a theory of appetite. Sensuous desire, on this account, is the conscious correlate of a literal physical lack, and free choice corresponds to an organism’s spontaneous motion to fill a specific void. The metaphysics thus reaches down into physiology: the same principle that explains why atoms swerve also explains why a hungry animal moves toward food.

Ethics as Therapy

Al-Razi’s Spiritual Physick (Tibb al-ruhani) opened by stating its analogy explicitly. Philosophy provides the medicine of the soul as medicine provides the physic of the body, and ethics is conceived as a kind of therapy rather than as a code of obligation. The model is Plato’s Gorgias, in which psychic health stands to the soul as bodily health stands to the body, but al-Razi’s procedure is naturalistic and empiricist: the philosopher diagnoses a psychological weakness and prescribes the regimen by which it can be brought back toward the natural state. The work was sufficiently provocative that the Isma’ili philosopher Nasir-i-Khusraw wrote a refutation called Academic Discourse.(Nasr, Seyyed Hossein & Leaman, Oliver (eds.), 1996)

The substantive ethical theory followed from al-Razi’s account of pleasure.(Nasr, Seyyed Hossein & Leaman, Oliver (eds.), 1996) He defined pleasure as the sensed return of the body to its natural state after some dislocation, and argued that all kinetic pleasure presupposes a prior dislocation, though the dislocation itself need not be consciously felt as pain.(Nasr, Seyyed Hossein & Leaman, Oliver (eds.), 1996) Following an Epicurean route, he arrived at mildly ascetic hedonism: intense indulgence deadens pleasure by making it habitual, while modest desires, tailored to nature, are most reliably satisfied and produce the greatest peace of mind.(Nasr, Seyyed Hossein & Leaman, Oliver (eds.), 1996)

The principles he derived were prudential rather than deontic. Lying, in al-Razi’s account, is rejected not because it is intrinsically wrong but because the liar can never be trusted and so can never enjoy peace of mind. Anger, taken to excess, defeats its own biological purpose. Moderation is understood physiologically, as what nature requires, rather than as the Aristotelian rational mean. Goodman observes that this therapeutic-prudential model was followed closely by Maimonides in his Eight Chapters, where ethics is similarly framed as the medicine of the soul and the rules of conduct are derived from a clinical reading of human psychological constitution.(Nasr, Seyyed Hossein & Leaman, Oliver (eds.), 1996)

Reason against Prophecy

The most contested of al-Razi’s positions was his rejection of prophetic religion. The argument was theological in form. God’s goodness, on al-Razi’s reading, demands that guidance be available to all human beings. Special revelation, by privileging one people as the standard-bearers of mankind and making the rest dependent on them, is incompatible with that universality. Goodman quotes al-Razi directly: “How can you imply that God would prefer one people as the standard bearers of mankind, making all the rest dependent on them? How can you reconcile with the wisdom of the Allwise God’s singling out one people in this way, setting mankind at one another’s throats, fomenting bloodshed, warfare and conflict!”(Nasr, Seyyed Hossein & Leaman, Oliver (eds.), 1996) What God’s goodness does provide, on this account, is the universal gift of intelligence. Prophetic experience is attributed instead to demonic spirits who deceive using vile bodies as their vehicles, and special prophecy is dismissed as imposture.

The position rests on an epistemology that places intellectual progress above the authority of any teacher. A philosopher, in al-Razi’s account, is defined not by membership in a school but by original inquiry. Goodman preserves the key passage: “every later philosopher who commits himself creatively, diligently and persistently to philosophical inquiry where subtle difficulties have led his predecessors to disagree will understand what they understood and retain it… Rapidly mastering what his predecessors knew and grasping the lessons they afford, he readily surpasses them. For inquiry, thought and originality make progress and improvement inevitable.”(Nasr, Seyyed Hossein & Leaman, Oliver (eds.), 1996) The Arabic word in the passage is ijtahada, the same root from which ijtihad derives in Islamic jurisprudence; al-Razi’s deployment of it to license individual philosophical progress against received authority is part of why his philosophical writing survived chiefly in the refutations written against him.

The political content of the position is plain. If every person is equally capable of thought, and if intellectual progress depends on individual inquiry rather than discipleship, then no one needs a leader to show them how to live. This Epicurean democratic epistemology, paired with the rejection of prophecy, made al-Razi one of the figures whom later Isma’ili theology had to address directly, and it explains why so much of his philosophical oeuvre is preserved in the form of hostile paraphrase.

The Challenge to Galen

Rhazes, who differed from Galen in essential philosophical points, justified his divergence by direct appeal to Galen’s own insistence on truth. To paraphrase Rhazes: It is more in the spirit of Galen to follow his exhortation to search for truth than it is to swear by his opinions.(Temkin, 1973)

This rhetorical move is precise and worth examining. Al-Razi did not attack Galen as an unworthy authority; he invoked Galen’s own epistemic commitments (his insistence on demonstration over assertion, observation over tradition) as the standard by which specific Galenic claims could be found wanting. A specific and telling example of this method: al-Razi was the first to refute Galenic humoral theory through experimental observation, demonstrating that warm drinks raised body temperature beyond the drink’s own temperature — a result that challenged the theory of temperament at its core and that Galenic logic could not readily accommodate.(Saad Said, 2011) The critique was Galenic in its method and anti-Galenic in some of its conclusions. Underlying this was al-Razi’s broader epistemological conviction that contemporary scholars, because of accumulated knowledge, are better equipped than the ancients, a stance that stimulated original scientific research and practical advancement rather than deference to inherited texts.(Saad Said, 2011)

Pormann and Savage-Smith, in Medieval Islamic Medicine (2007), identify al-Razi as “perhaps the most outstanding example of this analytical and questioning attitude” among Islamic physicians: a figure who combined genuine respect for the ancient texts with a willingness to test their recommendations and publish the results.(Pormann, 2007) Stapley notes that al-Razi’s scientific approach also led him to propose that new medicines be tested on monkeys before being given to patients, an early articulation of preclinical safety testing.(Stapley, 2024)

Sigerist, writing in 1933, contrasted al-Razi and Avicenna as two opposed types: the clinician working through individual case histories versus the systematist building a quasi-mathematical logical edifice modelled on Galenic and Aristotelian methods.(Henry E. Sigerist, 1933) According to Sigerist, al-Razi was “a musician and an imaginative man,” while Avicenna was “a purely logical thinker”; al-Razi was a clinician, but Avicenna was the systematist of Arabian medicine.(Henry E. Sigerist, 1933)

Clinical Method and the Book of Experiences

The closest surviving evidence for what al-Razi actually did with patients, as opposed to what he recommended in treatises, comes from the Kitab al-Mujarrabat, or Book of Experiences (also called Kitab al-Tajarib, the Casebook), compiled by his students after his death in 925 and available in a modern critical edition by Cristina Álvarez-Millán.(Pormann, 2007) Pormann and Savage-Smith preface their reconstruction of al-Razi’s practice with a methodological caution that applies to all such accounts: reliable evidence for the actual everyday practice of medieval Islamic medicine is genuinely scarce. Hospital records, administrative documents, and surviving surgical instruments are nearly absent, and knowledge of practice must be reconstructed primarily from case histories inserted into formal treatises and from notes recorded by students.(Pormann, 2007)

Álvarez-Millán notes that al-Razi died in 925 CE having directed hospitals in his home town of Rayy (near Tehran) and in Baghdad, and was a prolific author of medical writings.(Alvarez-Millan, Cristina, 2000) She describes the Casebook as “the largest and oldest collection of case histories known in medieval Islamic medical literature,” containing nearly 900 cases that al-Razi treated or supervised, recorded by a student after his death “for medical instruction,” making the text an “impartial source for studying actual medical practice as opposed to theoretical ideals.”(Alvarez-Millan, Cristina, 2000)(Alvarez-Millan, Cristina, 2000)

Álvarez-Millán’s analysis shows that most diagnoses in the Casebook are recorded by symptom rather than by humoral category.(Alvarez-Millan, Cristina, 2000) Entries such as “headache, pain and cough, accompanied by redness in the left eye” or “continuous fever, red urine without cough” illustrate this symptom-based description.(Alvarez-Millan, Cristina, 2000) The broader conclusion is that the medical knowledge and therapeutic advice carefully described in al-Razi’s theoretical works were not paralleled in his actual medical performance; learned treatises served other purposes than determining medical practice.(Alvarez-Millan, Cristina, 2000) One representative case shows the texture of his clinical judgment: a woman presented with darkened breasts and a hard, movable growth in one of them; al-Razi diagnosed cancer, noting that protruding cancers could be extirpated but this one did not protrude.(Alvarez-Millan, Cristina, 2000)

Pormann and Savage-Smith describe what the Book of Experiences shows: “it is evident that al-Rāzī’s therapy concentrated on evacuation (by phlebotomy, cupping, or purgatives), regimen, medicaments, and diet, with great reliance on rose-honey and barley water. Surgery is nowhere to be seen.”(Pormann, 2007)

Al-Razi did not simply apply the inherited humoral framework but revised it. He updated the properties of several humors based on his own clinical observations, argued that some diseases resulted from processes Galen’s theory did not adequately explain, and developed disease classification schemes that went beyond those in the Greek texts.(Saad Said, 2011) He also introduced the category of psychosomatic medicine more explicitly than his predecessors, describing conditions in which mental states produced measurable physical changes and treating the reciprocal relationship between mind and body as a legitimate clinical concern.(Saad Said, 2011) Among the materia medica he transmitted, al-Razi reported that Indian physicians had long used Ferula asafoetida as a principal botanical aphrodisiac, preserving this knowledge for subsequent Arab practitioners including Avicenna.(Saad Said, 2011)

The most discussed episode in the compendium is a passage from his Comprehensive Book (Kitab al-Hawi) concerning meningitis. Pormann and Savage-Smith describe it: al-Razi treated one set of patients with bloodletting while “intentionally neglecting to bleed a second. He remarks: ‘By doing that, I wished to reach a conclusion; and indeed all those of the latter group contracted meningitis.’”(Pormann, 2007) Pormann and Savage-Smith note that this approach “foreshadows later experimental methods, though al-Rāzī did not conceptualise it as a controlled trial in a modern sense.” The language of intentional comparison, keeping one group untreated in order to observe the difference, was unusual for the period and appears to reflect al-Razi’s particular investment in testing received recommendations rather than merely following them.

Al-Razi also pioneered urinalysis as a diagnostic tool. He described urine examination in detail, classifying urine by color, odor, and sediment to identify systemic illness — an approach Saad and Said identify as foundational to Arabic clinical chemistry.(Saad Said, 2011) He conducted what may be one of the first recorded dietary experiments when he fed a horse a controlled diet to observe the effects on its bodily secretions, reasoning that systematic observation of physiological responses to dietary changes could yield reliable clinical knowledge.(Saad Said, 2011) The same experimental impulse appears in his toxicological work: he tested the effects of mercury compounds on live animals before prescribing them to patients, applying a principle of preclinical safety evaluation that was unconventional in his era.(Saad Said, 2011)

He also preserved in the Comprehensive Book a recipe from another physician, Saʿid ibn Baksi, for acute gout: two mithqāls of colchicum, half a dirham of opium, and three dirhams of sugar. Pormann and Savage-Smith note that colchicine, the active ingredient of colchicum, is used in modern medicine for precisely the same purpose.(Pormann, 2007) Al-Razi’s role here was as compiler and transmitter rather than originator, but his practice of recording what physicians actually prescribed, rather than what Galen recommended, is characteristic.

Smallpox, Measles, and Hay Fever

Al-Razi’s treatise On Smallpox and Measles (Kitab fi al-jadari wa al-hasba) is noted as the first work in the history of medicine devoted exclusively to these diseases.(Nasr, Seyyed Hossein & Leaman, Oliver (eds.), 1996) He was the first physician to clinically and scientifically distinguish smallpox from measles, and his treatise on the subject was the first dedicated monograph on the topic in any language.(Saad Said, 2011) Pormann and Savage-Smith state that “the description of smallpox and measles occurs for the first time in Arabic literature” in this text, and also credit al-Razi with describing catarrh as an allergic reaction to rose scent, demonstrating the observational acuity of Islamic clinicians beyond their Greek sources.(Pormann, 2007) Goodman, surveying al-Razi’s medical output for the History of Islamic Philosophy, reaches the same conclusion in stronger form: the work’s clinical detail and empirical precision were unmatched in antiquity.(Nasr, Seyyed Hossein & Leaman, Oliver (eds.), 1996)

Sigerist’s appraisal in 1933 was characteristically careful. The treatise was, he observed, “one of the first monographs on a disease” in medical history. He noted a defect (measles and smallpox are not always sharply distinguished in al-Razi’s text) but emphasised that the work nonetheless contains “excellent clinical descriptions, and a vigorous spirit of observation breathes through it.”(Henry E. Sigerist, 1933)

The treatise describes the prodromal symptoms, the character of the eruption, and the differential features that distinguish the two diseases at various stages: the kind of detailed observational work that required systematic comparison of many cases rather than reliance on a single theoretical framework. Ackerknecht, who surveys al-Razi briefly in his Short History of Medicine (1955), confirms the treatise’s historical significance but attaches a sharper judgment: despite being “the most observation-minded of the Arab writers,” al-Razi “said that a thousand books were better than a thousand years of observation.”(Ackerknecht, 1955) Ackerknecht presents this as characteristic of medieval medicine’s deference to textual authority even among its most empirically inclined practitioners. The tension is genuine: al-Razi’s practice shows a man who tested claims carefully; his stated epistemology remained, at least in some formulations, on the side of the bookish tradition.

The treatise retained its authority long after the medieval period. Stapley notes that when an English translation was issued in 1747, the preface was written by Dr Mead, who called al-Razi “the greatest physician of the age he lived in”; Mead’s endorsement shows that the smallpox treatise was still regarded as a serious clinical contribution seven hundred years after it was written.(Stapley, 2024) Stapley also records al-Razi’s clinical observation that measles arises from bilious blood, producing a state of nausea and anxiety — a humoral classification that distinguished measles from smallpox’s characteristic back pain in a way that made differential diagnosis practicable.(Stapley, 2024)

The same acuity of observation appears in a smaller note that Pormann and Savage-Smith single out: al-Razi’s description of catarrh produced by the scent of roses, what would now be called allergic rhinitis, or hay fever. He described this as a distinct clinical pattern apparently unknown to the Greeks, and it stands as one of the first recorded descriptions of an allergic response in any medical literature.(Pormann, 2007)

Mind, Body, and Spiritual Medicine

Al-Razi also wrote al-Tibb al-Ruhani (On Spiritual Medicine), which addressed psychotherapy and moral diseases and their effect on human behavior.(Saad Said, 2011) He recommended that physicians make patients believe they will recover, reasoning that “the state of the body is linked to the state of the mind” — an explicit articulation of the mind-body relationship that went beyond the standard Galenic framework.(Saad Said, 2011) The text argued that the “afflictions of the soul” (desire, regret, fear, produced by greed, lust, anger, envy, or fear of death) damage bodily health. Pormann and Savage-Smith summarise its programme: al-Razi made a case for the pursuit of pure knowledge and the avoidance of these mental afflictions both as a philosophical imperative and as a path to bodily health, linking moral philosophy directly to medicine.(Pormann, 2007) On the specific question of sexual excess, Pormann and Savage-Smith quote al-Razi directly: sexual intercourse “‘weakens the eyesight, wrecks and exhausts the body, speeds up aging, senility, and withering, damages the brain and the nerves, and renders the [bodily] strength weak and feeble, in addition to many other conditions which would take too long to mention.’”(Pormann, 2007) This concern with the intersection of conduct and health reflects a broad Galenic tradition (Galen himself wrote on the relationship between moral character and bodily constitution) rather than a distinctively Razian departure. The fuller theoretical apparatus of On Spiritual Medicine, including its account of pleasure as the return to natural state and its prudential rather than deontic ethics, is treated above in “Ethics as Therapy.”

Al-Razi’s approach to mental illness was similarly grounded in physical rather than supernatural causes. Stapley records that he sought damage to the brain and nerves, or deprivation and suffering earlier in life, as explanations for psychiatric conditions, and that he established a dedicated area within his hospital for treating psychiatric patients — a structural commitment to mental illness as a legitimate medical concern rather than a moral or spiritual problem.(Stapley, 2024)

Al-Razi’s place in the longer history of the doctrine of nature’s healing power is secured in part through Avicenna’s later articulation. Neuburger, writing in 1943, names al-Razi alongside Avicenna and Maimonides as Islamic physicians who affirmed that “natural healing power alone suffices in many cases,” and reports Avicenna’s framing of disease as a contest between nature and a foreign enemy in which the crisis is the decisive moment. The maxim Avicenna gave the tradition, that “the true healer is man’s own strength and not his doctor, since the doctor merely takes means to establish strength,” describes a clinical posture that al-Razi’s own practice of evacuation, regimen, and waiting on nature substantially anticipates.(Neuburger, 1943) The vis medicatrix naturae of later European medicine is in part a continuation of this Arabic synthesis.

Al-Razi also accepted the standard framework that connected celestial influence to disease. Siraisi quotes him as saying: “Wise men among the medici agree that everything relating to times, the air, and waters, and complexions, and diseases is changed by the motion of the planets.”(Siraisi, 1990) This was not an idiosyncratic position but a piece of received Hippocratic-Galenic doctrine, in which environmental air, complexion, and celestial motion together formed a single causal field. The remark belongs alongside the Baghdad hospital-siting story: both reflect a clinical world in which the air’s quality, shaped by season, place, and the heavens, was a primary object of medical attention.

Food Therapy and the Therapeutic Hierarchy

Al-Razi’s clinical priorities were captured in a maxim that circulated widely: “As long as you can heal with food, do not heal with medication.”(Saad Said, 2011) This formulation expressed a therapeutic hierarchy — physiotherapy and diet first, drugs second, surgery last — that Saad and Said identify as one of the organizing principles of the entire Greco-Arab medical system.(Saad Said, 2011) Al-Razi was among the advocates of this graduated approach, which proceeded from diet therapy, to simple drugs, to compound drugs, and finally to surgery, with each stage entered only when the previous had failed.(Saad Said, 2011)(Saad Said, 2011) The Al-Hawi preserves specific applications of this principle in the pharmacology of honey, which al-Razi recommended for dental hygiene and wound treatment: his text prescribes mixing honey with vinegar as a daily mouthwash to maintain healthy teeth and gums, and describes honey’s preservative properties, noting that it does not spoil and may even be used to preserve cadavers.(Saad Said, 2011) The Al-Hawi’s food-medicine content was sufficiently comprehensive that when it was translated into Latin in the thirteenth century and circulated under the title Liber Continens, it carried this dietary therapeutics alongside its other clinical material into European university medicine, where it remained a standard textbook until the 1700s.(Saad Said, 2011)

Practice Settings and Ethics

Al-Razi practiced medicine in multiple venues characteristic of elite physicians in the medieval Islamic world: hospital practice, palace visits, and home consultations. Pormann and Savage-Smith identify him alongside al-Kaskari as typical of physicians who “combined hospital practice with palace visits and home consultations,” occupying a social position well above market practitioners.(Pormann, 2007)

On the ethics of the profession, he appears in the literature as someone who genuinely urged restraint in pursuit of financial gain. Pormann and Savage-Smith note that al-Razi was among the physicians who “urged physicians not to strive after financial gain.”(Pormann, 2007) He was also attentive to the presence of fraud: he documented charlatan tricks (such as hiding worms in a patient’s mouth to simulate their extraction) while at the same time “approved of Galen’s therapeutic deception when used for patient benefit.”(Pormann, 2007) The two positions are consistent with a view that what matters is the patient’s welfare, not the truth of the performance.

[GAP: Pormann and Savage-Smith situate al-Razi’s ethical writings within a broader function the genre served.] Codes of medical ethics in the medieval Islamic world set out an ideal physician as competent, well-spoken, properly dressed, kind, and discreet, but the same codes also legitimated some practitioners by excluding rivals as charlatans, with mastery of Greek-derived theory functioning as the touchstone of orthodoxy.(Pormann, 2007) [GAP: Al-Razi’s own treatise On Examining the Physician belongs to this regulatory literature; his urging of restraint over profit is therefore both a moral position and a piece of professional boundary-drawing.]

Pormann and Savage-Smith observe that even formally trained learned physicians wrote treatises on occult medicinal properties, the khawass genre, demonstrating the coexistence of rigorous clinical observation and occult belief.(Pormann, 2007) The basic premise of khawass literature was that every substance in nature possessed hidden properties activatable without prayer or invocation; the material itself, or symbols inscribed upon it, was held to be sufficient.(Pormann, 2007) Additionally, magic-medicinal bowls first appeared in the twelfth century, with the earliest known made for Syrian ruler Nur al-Din ibn Zangi; surviving bowls indicate that the most feared ailments requiring magical intervention were scorpion stings, mad-dog bites, snake bites, and gastrointestinal complaints.(Pormann, 2007)

Alchemy as Proto-Chemistry

Al-Razi’s alchemical writings, compiled in the Kitab sirr al-asrar (later known in Latin as the Secretum secretorum), occupy an unusual position in the history of the genre. Goodman’s account distinguishes them sharply from the hermetic tradition. Where most alchemical literature trafficked in symbolic reagents and ritual procedure, al-Razi’s recipes drew on trade substances obtainable from markets, kitchens, mines, and laboratories, and his methods, while still pre-modern, approached chemistry rather than occultism. He grouped materials under six rubrics: four spirits, seven bodies, thirteen stones, five vitriols, six boraxes, and eleven salts.(Nasr, Seyyed Hossein & Leaman, Oliver (eds.), 1996)

The conceptual ambition was striking. The aim was to traverse the boundaries dividing one type of substance from another by means of a powerful agent that would permeate and transform a substrate, adding or removing specific properties. Goodman frames the underlying move as a step toward the quantitative reduction of qualitative properties: al-Razi was working toward a level of explanation in which observed qualitative changes could be analysed in terms of the rearrangement of underlying particles. His experimentalism, Goodman concedes, was rudimentary, held in check by inadequate theory just as the theory was held in check by insufficient experience. But the direction of travel was clear, and it connects directly to his atomism. The same physical primitives that grounded the cosmogony also grounded his chemical practice.

Major Works

The Kitab al-Hawi (Comprehensive Book; Latin: Liber Continens). Al-Razi’s largest work, an encyclopedic compilation of Greek, Arabic, and Indian medical knowledge organized by topic. Sigerist describes the Hawi as a “huge compilation, a sort of encyclopaedia of the medical knowledge of his day, so compendious that the Arabs spoke of it as El-Hawi — Latinised as Continens.” It was a posthumous work, not penned by al-Razi himself but assembled after his death by his pupils, and it recorded and elaborated all that had been known to Greek, Arabian, and Indian physicians, with the addition of al-Razi’s own observations. It is from study of this book, more than anything else, that Sigerist concluded al-Razi to have been “the greatest clinician of the world of Islam.”(Henry E. Sigerist, 1933) Goodman specifies the scale: the Hawi, compiled posthumously by his students from his private notes, ran to twenty-five volumes, a measure of how thoroughly al-Razi had documented his clinical practice in writing intended originally for himself.(Nasr, Seyyed Hossein & Leaman, Oliver (eds.), 1996) The Hawi included materia medica arranged alphabetically, compounded drugs, pharmaceutical dosage forms, and animal-source drugs.(Saad Said, 2011) Gerard of Cremona (d. 1187) later translated al-Razi’s Kitab al-Mansuri (the Book for al-Mansur, a smaller practical compendium dedicated to the Samanid governor al-Mansur ibn Ishaq) into Latin; this became one of the most widely circulated Arabic medical texts in European universities.(Pormann, 2007)

The Kitab al-Mansuri (Book for al-Mansur; Latin: Liber Almansoris). A ten-volume practical medical encyclopaedia, more systematic and finished than the Hawi. Four of the ten treatises covered diets, drugs, medicated cosmetics, toxicology and antidotes, and compounded remedies.(Saad Said, 2011) The ninth book of this compendium, which dealt with clinical medicine from head to foot, circulated widely in Latin translation and was taught in European medical schools.

The Kitab fi al-jadari wa al-hasba (On Smallpox and Measles). Ullmann confirms that this treatise was the first work in any medical literature to fully treat smallpox and describe the differential symptoms distinguishing it from measles: back pain is typical of smallpox, while restlessness, nausea, and dejection are more common in measles.(Ullmann, 1978)

The Kitab al-Tibb al-Ruhani (On Spiritual Medicine). The philosophical-ethical work connecting conduct, mental states, and health, structured as the medicine of the soul on analogy with the physic of the body.

The Shukuk ‘ala Jalinus (Doubts about Galen). The polemical work on Galenic error.

The Kitab al-Mujarrabat (Book of Experiences). The posthumous collection of roughly 900 case histories assembled by his students, discussed in detail in the section on clinical method above.

The Man la Yahduruhu Tab (He Who Has No Physician to Attend Him). Al-Razi was the first in the Arab-Islamic world to write a medical book specifically for the general public, dedicated to the poor, the traveller, and those who lacked access to a trained physician.(Saad Said, 2011)

The Kitab sirr al-asrar (Book of the Secret of Secrets; Latin: Secretum secretorum). Al-Razi’s principal alchemical work, organising materials under the six rubrics described above and approaching chemistry rather than hermetic mysticism.(Nasr, Seyyed Hossein & Leaman, Oliver (eds.), 1996) His two best-known alchemical texts also addressed the identification of plant-, animal-, and mineral-based drugs, connecting his chemical investigations to pharmacological practice.(Saad Said, 2011)

Legacy in the Latin West

Siraisi, in Medieval and Early Renaissance Medicine (1990), places al-Razi in the first tier of Islamic physicians whose work shaped the medical curriculum in European universities: alongside Haly Abbas (al-Majusi), Avicenna, Albucasis (al-Zahrawi), and Averroes, “Rhazes” was among those whose translations “became the basis for further elaboration” in European scholastic medicine.(Siraisi, 1990) Siraisi also notes the specifically surgical line of transmission: Book 6 of Paul of Aegina, “the most detailed account of ancient surgical practice to have come down to us,” was extensively used by Rhazes, Haly Abbas, Albucasis, and Avicenna, and the works of these Arabic encyclopaedists in turn provided the medieval Latin West with substantial technical writing on surgery ultimately deriving from the Hippocratic corpus.(Siraisi, 1990) Al-Razi’s Hawi therefore functioned in Europe not only as a clinical compendium but as one of the channels through which Hellenistic surgical knowledge re-entered the Latin curriculum.

The institutional pathway by which al-Razi’s Arabic texts reached Europe is also recoverable. Sigerist describes Constantine of Africa as the figure who “made an eloquent gesture towards the East” with translations that opened a new world of medical learning at Salerno; in 1085 Toledo fell to Alfonso VI of Castile, and during the latter half of the twelfth century an Italian, Girardo (Gerard) of Cremona, made his way to Toledo, learned Arabic, and ransacked the libraries, bringing the Latin West into full possession of Aristotle, Euclid, Ptolemy, and previously unknown Galenic and Hippocratic works.(Henry E. Sigerist, 1933) Pormann and Savage-Smith’s chronological tables make the same point graphically: al-Razi’s death in 925 and Avicenna’s in 1037 fall in an “East” column whose Western counterpart remains effectively empty; Constantine the African (d. before 1099) is the first figure to appear in the “West” column during a period of active Islamic scholarship, a visual encoding of the temporal lag between Islamic production and European reception.(Pormann, 2007)

The persistence of al-Razi’s authority in European pharmacological practice is visible in the 1618 Pharmacopoeia Londinensis, which included a large representation of Arabic formulas alongside classical sources; Stapley records that the Pharmacopoeia contained preparations attributed to Rhazes alongside those of Haly Abbas, Avicenna, Nicolai of Salerno, and Galen, confirming that six centuries after his death al-Razi was still a named authority in institutional European medicine.(Stapley, 2024)

The measure of al-Razi’s penetration into European literary culture is provided by a detail Pormann and Savage-Smith observe in passing: Chaucer’s Canterbury Tales (c. 1390), in the General Prologue’s catalogue of the Physician’s reading, names four medieval Islamic medical writers alongside Greek authorities, and al-Razi appears among them as “Razis.”(Pormann, 2007) He had become, by the late fourteenth century, a standard fixture of educated medical culture in England, France, and Italy, known not through Arabic but through the Latin translations of his works, chiefly the Liber Almansoris in Gerard of Cremona’s version.

The Latin reception did not preserve al-Razi’s critical edge. His challenges to Galen were known, but the dominant use of his work in European universities was encyclopedic rather than polemical: the Liber Continens and Liber Almansoris as compendia of medical information, not as models of independent clinical judgment. The philosopher who had written Doubts about Galen was largely absorbed into the Galenic textual tradition he had critiqued.

Paracelsus, in the sixteenth century, named al-Razi as one of the authorities whose books should be discarded, placing him alongside Galen and Avicenna as representatives of the corrupt textual tradition that stood between physicians and direct experience of nature. Temkin records Paracelsus’s judgment: “The light of nature did not shine in the books of Avicenna, Galen, Mesue, Rhazes, and all the others.”(Temkin, 1973) The irony is considerable: a physician who had argued for testing received doctrine against clinical observation was classified by Paracelsus as an obstacle to doing exactly that. The classification reflects how thoroughly al-Razi had been absorbed into academic authority by the time Paracelsus was burning books: he had become, in European medicine, what he had argued against in his own.

This section is reserved for Thomas Easley’s annotations, corrections, and additions. AI-generated content above this line; human-edited content below.

See Also

• galen: The authority al-Razi challenged and worked within
• avicenna: The next generation; absorbed al-Razi’s clinical legacy into a more systematic framework
• humoral-theory: The framework al-Razi accepted while contesting specific claims within it
• islamic-medicine: The broader tradition in which al-Razi practiced
• kitab-al-hawi: His encyclopedic compendium
• smallpox: The disease al-Razi first distinguished from measles
• gerard-of-cremona: The translator who brought al-Razi’s work into Latin
• paracelsus: The later critic who, paradoxically, classified al-Razi as part of the tradition he opposed

Sources

Pages in this entry draw on the following evidence cards:

• Pormann, Peter E. and Emilie Savage-Smith. Medieval Islamic Medicine. Edinburgh University Press, 2007. Evidence cards: pormann07-ch03-005, pormann07-ch03-007, pormann07-ch03-010, pormann07-ch03-011, pormann07-ch04-004, pormann07-ch04-006, pormann07-ch04-007, pormann07-ch04-009, pormann07-ch04-010, pormann07-ch05-001, pormann07-ch05-002, pormann07-ch05-003, pormann07-ch05-004, pormann07-ch06-006, pormann07-ch06-007, pormann07-ch06-008, pormann07-ch07-001, pormann07-ch07-002, pormann07-ch08-001, pormann07-ch09-003, pormann07-ch10-004.
• Sigerist, Henry E. The Great Doctors: A Biographical History of Medicine. 1933. Evidence cards: sig33-ch02-001, sig33-ch02-002, sig33-ch02-003, sig33-ch02-004, sig33-ch02-007, sig33-ch02-008, sig33-ch02-009, sig33-ch02-010.
• Ackerknecht, Erwin H. A Short History of Medicine. 1955. Evidence card: ack55-ch09-002.
• Temkin, Owsei. Galenism: Rise and Decline of a Medical Philosophy. Cornell University Press, 1973. Evidence cards: temkin73-ch02-004, temkin73-ch02-005, temkin73-ch02-007, temkin73-ch03-011, temkin73-ch04-009.
• Siraisi, Nancy G. Medieval and Early Renaissance Medicine. University of Chicago Press, 1990. Evidence cards: siraisi90-ch01-006, siraisi90-ch05-004, siraisi90-ch06-001.
• Neuburger, Max. The Doctrine of the Healing Power of Nature. 1943. Evidence card: neuburger43-ch02-007.
• O’Leary, D.L. (1949; repr. 2015). How Greek Science Passed to the Arabs. London: Routledge. [Source ID: oleary-how-greek-science-2015]. On the Arab Aristotelian school, al-Kindi’s founding role, and the court-patronage context that shaped Arabic scientific life.
• Goodman, Lenn E. Islamic Humanism. Oxford University Press, 2003. Evidence card: good-ih03-ch04-004.
• Álvarez-Millán, Cristina. “Practice versus Theory: Tenth-century Case Histories from the Islamic Middle East.” Social History of Medicine 13 (2000). Evidence cards: alvm00-ch01-001, alvm00-ch01-002, alvm00-ch01-005, alvm00-ch01-009, alvm00-ch01-010, alvm00-ch01-011.
• Ullmann, Manfred. Islamic Medicine. Edinburgh University Press, 1978. Evidence card: ullmann78-ch06-008.
• Goodman, Lenn E. “Muḥammad ibn Zakariyyāʾ al-Rāzī.” In Seyyed Hossein Nasr and Oliver Leaman (eds.), History of Islamic Philosophy. London: Routledge, 1996, ch. 13. Evidence cards: nl96-ch13-001, nl96-ch13-002, nl96-ch13-003, nl96-ch13-004, nl96-ch13-005, nl96-ch13-006, nl96-ch13-007, nl96-ch13-008, nl96-ch13-009, nl96-ch13-010. Lead authority on al-Razi’s philosophical biography (five eternal principles, Soul’s clinamen, Epicurean atomism, prudential ethics, rejection of prophecy, alchemy as proto-chemistry).

Editorial Notes

• [GAP: specialist source needed — Savage-Smith’s Bodleian catalogue (2011) is a specialist bibliographic reference unlikely to be acquired; Latin print transmission history of On Smallpox requires manuscript-studies expertise]
• [GAP: specialist source needed — Mohaghegh’s 1993 Tehran edition of Shukuk not widely available outside specialist libraries; Strohmaier’s analysis in German-language Arabistik journals not in Library]