Pormann PE (2013). Qualifying and quantifying medical uncertainty in 10th century Baghdad: Abu Bakr al-Razi.
Email to someoneTweet about this on TwitterShare on FacebookPin on PinterestShare on LinkedIn

© Peter E. Pormann, School of Arts, Histories and Cultures, University of Manchester, Oxford Road, Manchester M13 9PL. Email: peter.pormann@manchester.ac.uk

Cite as: Pormann PE (2013). Qualifying and quantifying medical uncertainty in 10th century Baghdad: Abu Bakr al-Razi. JLL Bulletin: Commentaries on the history of treatment evaluation (http://www.jameslindlibrary.org/articles/qualifying-and-quantifying-medical-uncertainty-in-10th-century-baghdad-abu-bakr-al-razi/)


Abu Bakr Muhammad ibn Zakariyaʾ al-Razi (d. 925) was one of the most interesting and innovative clinicians of the medieval world (Iskandar 2011). He distinguished smallpox from measles; experimented on an ape to establish the toxicity of quicksilver (mercury) and he used a control group to assess whether blood-letting was an effective treatment for ‘brain fever’ (al-Razi, al-Kitab al-Hawi, ed. Hyderabad i. 122; Savage-Smith 1996; Tibi 2005). Al-Razi stated in one of his treatises:

My aim and objective is [to provide] things useful to people who practise and work, not for those engaged in research and theory (cited in Pormann 2008, pp 112–113)

Hospitals in 10th-century Baghdad

Al-Razi rose to become a hospital director in both Rayy (his home town, and now a suburb of Teheran) and in Baghdad. This hospital environment proved important for his medical research. By the tenth century, hospitals in Baghdad had developed into quite sophisticated institutions. For instance, in the 920s and 930s, a powerful vizier by the name ʿAli ibn ʿIsa endeavoured to improve public health, both by maintaining hospitals and sending doctors to areas where there was inadequate medical provision. The hospitals were Islamic charitable foundations with sometimes substantial endowments, so they benefitted from both legal and financial security; but ʿAli ibn ʿIsa specified that they should serve non-Muslims as well as Muslims (Pormann 2010).

Moreover, the medicine practised in these hospitals was not based on religious beliefs, but on the humoral pathology inherited from the Greeks, as the writings of the hospital physician al-Kaskari demonstrate (Pormann 2003). In this sense, the Islamic hospitals offered—somewhat paradoxically—a non-religious and non-sectarian service: physicians and other practitioners from various backgrounds catered for equally diverse patients in a non-confessional medical system. The development of the hospitals meant that elite medicine moved to them, and some of the most highly regarded doctors looking after patients in the upper echelons of society worked and taught in them. In addition, given their large numbers of patients, hospitals provided an infrastructure for research.

Hospital records

Following Hippocrates’ example in recording cases, al-Razi stressed the fundamental importance of documenting the characteristics and treatment of hospital patients, and more than two thousand of these case notes have survived (Álvarez-Millán 2000). In Doubts about Galen (Al-Shukuk ʿala Jalinus), al-Razi referred to registers of hospital patients’ names and notes as a basis for criticising the Greek physician Galen of Pergamum (c. 129–216):

How many things have I observed in the hospitals in Baghdad and Rayy, and in my own home. I shall explain the many meanings of these things. I recorded the names of those whose situation developed in accordance with these books [by Galen], and the names of those whose states developed exactly in the contrary fashion. The number of those whose state developed in a contrary fashion is not a small one. (Pormann 2008, pp 105–106)

Conceptualising patient groups

The hospital environment and record keeping promoted the conceptualisation of groups of similar patients, for which al-Razi uses the word jamaʿa.  One example concerns ophthalmological disorders (al-Razi, al-Kitab al-Hawi, ed. Hyderabad i. 142, lines 2–3):

I say: I am of the opinion that bloodletting at the corners of the eye and the vein of the forehead is useful against all chronic eye diseases such as inveterate pannus, trachoma (jarab), and red ‘ulcerative blepharitis’ (al-sulaq al-ahmar). In front of me, a group (jamaʿa) was phlebotomised who were suffering from pannus. It [the pannus] receded and they were able to rest.

Another example relates to the treatment of epilepsy (al-Razi, al-Kitab al-Hawi, ed. Hyderabad ii. 28, lines 4–9):

I say: A sternutatory (saʿut) [a substance provoking sneezing] that is excellent for epilepsy; a group was cured by it (buriʾa ʿalaihi jamaʿatun). Let the patient take a sternutatory made with sneezewort, white hellebore, cyclamen, and colocynth pith.

In both these examples, al-Razi remarks that a group of patients was positively affected by treatments that he had recommended.

Quantifying treatment success

Elsewhere, in Doubts about Galen, al-Razi reports the proportions of groups of patients who were treated successfully.

One such quotation concerns a condition called ‘drum-like dropsy’, a type of dropsy in which the lower abdomen is so swollen that it sounds like a drum on percussion. Galen said that when certain intestinal pains are located around the navel or the small of the back, this sometimes resulted in drum-like dropsy. Al-Razi only partially agrees with Galen here, saying:

I have seen this more than once in the hospitals (bimaristanat) in Iraq, and in my home in Rayy. In some of them [the patients], drum-like dropsy followed, but in others strangury, and in yet others a pain in the hip. Since I noticed this many times, whilst neither purging nor warm drugs that expel wind were of any help for them, I applied myself to giving them enemas that provide heat and fatten the region of the kidneys. I made them sit in warm sand up to their chest. I made some of them constantly attend dry baths [i.e. hot rooms with little moisture]. Three were cured whilst one was affected by dropsy more quickly than those who were not treated (Buriʾa minhum thalathatu nafarin wa-asraʿa l-istisqaʿu ila nafarin asraʿa mimman lam yuʿalaj), but by a lighter [variety of dropsy]. I did not, however, see that anyone recovered from ‘drum-like’ dropsy. (ed. Muhaqqiq, p. 74, line 20-p. 75, line 6 with corrections based on a fresh examination of the manuscripts) (al-Razi 10th century CE)

In other words, according to al-Razi, the type of pain described by Galen only sometimes resulted in drum-like dropsy. In any case, al-Razi wanted to prevent this dropsy from occurring and he devised a way of lessening the possibility. When commenting on the effectiveness of this method, al-Razi resorts to crude statistics —  three were cured, whereas one contracted a lighter variety of dropsy — which we must assume was not fatal, as drum-like dropsy was. [It should be stressed that the text of the manuscripts is rather difficult here, and I give my current reading of the Arabic in brackets, revising my earlier interpretation (Pormann 2008: 104)].

Another example concerns a more impressive numerator and denominator.

A careful intellectual ought not to desire in this method the utmost certainty, and ought not to rely on it [the method] and make absolute statements on prognoses or deduce the treatment and regimen in accordance with it [the method]. For there were approximately three hundred out of two thousand patients (wa-qad kanu ʿala thalathati miʾatin min nahwi alfay maridin) whose state developed in a contrary fashion. I therefore refrained from announcing what was happening except where the patient’s situation was clearly and strongly indicated, so that I could have no doubt about it. For a time I continued seeking through experience [tajriba] and reason [qiyas] a new regimen for acute diseases in which I could be sure to avoid any mistake which would affect the patient—my only fault being my inability to find a speedy cure—until I found it. (Muhaqqiq p. 63, lines 14–18, with corrections). (al-Razi 10th century CE)

Al-Razi does not make clear for which condition he is seeking a new treatment, apart from the fact that it is acute. Only the hospital environment could provide such large numbers (‘two thousand’) and thus make it possible for al-Razi to seek out new cures, or, to put it in more modern terms, to conduct medical research.

Did al-Razi adhere to the theoretical concept of the patient group that became so important in Europe from the seventeenth century onwards (Morabia 2004; 2011)? There is at least one example of his use of a control group when trying to assess whether bloodletting is effective against brain fever (Al-Razi’s Comprehensive Book al-Kitab al-Hawi ; Savage-Smith 1996; Tibi 2005).  Although al-Razi does not offer a theoretical discussion highlighting the concept of the group, it is clear that he regarded numerical observation as important, and he mentions how different patient groups are affected differently by certain treatments.

Qualifying medical experience

Galen observed that one cannot rely on any and all experience: one needs to make sure that experience meets certain standards (van der Eijk 2005). He also insisted that the individual nature of a patient—what many physicians call idiosyncrasy – cannot be grasped (Reinhardt 2011). Although al-Razi fervently believed in the importance of experience, he also used the first Hippocratic aphorism to warn that ‘experience is dangerous’. As illustrated in the text referring to 2000 patients, however, al-Razi makes an epistemologically more astute point: the physician should be aware that complete certainty cannot be attained in medicine, perhaps especially when dealing with acute diseases. Two centuries after al-Razi, Abd al-Latif al-Baghdadi reminded his readers, that medicine is the ‘knowledge of probabilities’, and that this requires conjecture according to the rules of the art of medicine (Joosse and Pormann 2008; 2012).

This James Lind Library commentary has been republished in the Journal of the Royal Society of Medicine 2013;106:370-372. Print PDF


Al-Razi. Al-Kitab al-Hawi fi l-tibb. Osmania Oriental Publications Bureau, Osmania University, Hyderabad, India, 1955–75.

Álvarez-Millán C (2000). Practice versus theory: tenth-century case histories from the Islamic Middle East. In: Horden P, Savage-Smith E, eds: The Year 1000: Medical practice at the end of the first millennium. Special issue of Social History of Medicine 13.2, Oxford: Oxford University Press, pp 293–306.

Iskandar AZ (2011). Ar-Razi, the Clinical Physician (Ar-Razi al-tabib al-Ikliniki)’, in Pormann PE, ed. a: i. pp 207–53.

Joosse NP, Pormann PE (2008). Archery, mathematics, and conceptualising inaccuracies in medicine in 13th century Iraq and Syria. JLL Bulletin: Commentaries on the history of treatment evaluation (www.jameslindlibrary.org)

Joosse NP, Pormann PE (2012). Commentaries on the Hippocratic Aphorisms in the Arabic Tradition: The Example of Melancholy. In: Pormann, PE. Epidemics in Context: Greek Commentaries on Hippocrates in the Arabic Tradition, Scientia Graeco-Arabica 8 (Berlin: De Gruyter), pp 211–249.

Morabia A, ed. (2004). A history of epidemiological methods and concepts. Basel: Birkhauser.

Morabia A (2011). Santé: distinguer croyances et connaissance. Paris: Odile Jacob.

Muhaqqiq M, ed. (1993), Al-Razi: Shukuk ʿala Jalinus (Doubts about Galen) (Tehran: Maʿhad al-dirasat al-islamiya, Jamiʿat Tihran and Al-Maʿhad al-ʿali al-ʿalami li-l-fikr wa-l-hadara al-islamiya).

Pormann PE (2003). Theory and practice in the early hospitals in Baghdad — al-Kaškari ‘On Rabies and Melancholy’. Zeitschrift für Geschichte der Arabisch-Islamischen Wissenschaften 15:197–248.

Pormann PE (2008). Medical methodology and hospital practice: the case of Fourth/Tenth Century Baghdad. In the Age of al-Farabi. Arabic philosophy in the Fourth/Tenth Century. Warburg Institute Colloquia 12, pp 95-118.:

Pormann PE (2010). Islamic Hospitals in the Time of al-Muqtadir. In Nawas J ed., Abbasid Studies II: Occasional Papers of the School of ‘Abbasid Studies, Leuven, 28 June – 1 July 2004, Orientalia Lovaniensia Analecta 177 (Leuven; Dudley, Mass.: Peeters), 337–82; reprinted in Pormann 2011, i. 136–78.

Reinhardt T (2011). Galen on Usayable Properties. In: Oxford Studies in Ancient Philosophy 40. 2011, 297–317.

Savage-Smith E (1996). Medicine. In: Rashed R, ed. Encyclopedia of the history of Arabic science. London: Routledge, pp 903–61.

Tibi S (2005). Al-Razi and Islamic medicine in the 9th Century. JLL Bulletin: Commentaries on the history of treatment evaluation (www.jameslindlibrary.org)

van der Eijk PhJ (2005). Galen’s use of the concept of “Qualified Experience” in his dietetic and pharmacological works, in Eijk, ed, Medicine and Philosophy in Classical Antiquity: Doctors and Philosophers on Nature, Soul, Health and Disease Cambridge: Cambridge University Press, pp 279–98.