The Medical Influence of Rhazes

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The Medical Influence of Rhazes


The Persian physician known as Rhazes (c. 865-c.923), or ar-Rhazi (Abu Bakr Muhammad ibn Zakariya' ar-Razi) is primarily remembered for his encyclopedia of medicine and for his pioneering work on differentiating between smallpox and measles. His great synthesis of Greek and Arabic medical learning was first published under the title Kitab al-hawi, but it is better known in the form of a Latin translation published in 1279 as the Liber continens. The work was considered quite controversial at the time because of the author's willingness to criticize the Greek physician Galen (c. 130-c. 200), generally considered an infallible source of medical knowledge. For almost three centuries, the Liber continens served as the main source of Western therapeutic knowledge. Rhazes' book A Treatise on Smallpox and Measles has become a landmark in the development of the concept of specific disease entities and the value of diagnostic precision.


The Middle Ages of European history roughly correspond to the golden age of Islam, the religion founded by the prophet Muhammad (570-632). Just as Latin served as the common language of learning for students throughout Europe, Arabic was the language of learning throughout the Islamic world and Persians, Jews, and Christians took part in the development of Arabic medical and scientific literature. Pharmacology, optics, chemistry, and alchemy were of particular interest to Arab scientists.

For many European scholars, so-called Arabian medicine was significant only in terms of the role it played in preserving Greek philosophy during the European Dark Ages. Until rather recent times, European scholarship generally dismissed evidence of originality in the works of medieval Arabic medical and scientific writers and assumed that the primary accomplishment of Arabic science, medicine, and philosophy was the preservation and transmission of ancient Greek learning. In general, however, medieval scholars, physicians, and philosophers accepted the writings of the ancients as true and authoritative. Since the 1970s scholars have redefined "Arabian medicine" as "Islamic medicine," in reference to the translation, assimilation, and transformation of the texts, theories, and concepts of the ancient Greek philosophers which were introduced into Arab countries in the ninth century. For contemporary scholars, Islamic medicine, therefore, reflects the assimilation, integration, and development of the many elements that formed Islamic culture.

The writings of Islamic physicians and philosophers, which were often presented as commentaries on the work of Galen, were eventually translated from Arabic into Latin and served as fundamental texts in European universities. Medieval physicians and scholars, whether Muslims, Jews, or Christians, generally shared the assumption that Galenism was a complete and perfect system. Thus, many new insights into the history of science and medicine have been revealed through attempts to study the work of Islamic writers, such as Rhazes, on their own terms.


Although medieval physicians, Muslim and Christian alike, generally assumed that Galenism was a complete and perfect system, the great sages of Islamic medicine are worth studying in their own right, not just in terms of their role in preserving classical medicine. Latin translations of the medical writings of Rhazes, Avicenna (Ibn Sina, 980-1037), Haly Abbas, Averroës (Ibn Rushd, 1126-1198), and Albucasis (al-Zahrawi, 936-1013), were most influential in Europe, but many of these writers were also well known as philosophers and alchemists.

Rhazes has long been honored as one of the greatest physicians of the Islamic world, as well as one of the most scientifically minded physicians of the Middle Ages. A man of remarkable energy and productivity, Rhazes was the author of at least 200 medical and philosophical treatises, including the famous Continens, or "Comprehensive book of medicine." Although Rhazes claimed that the work was still incomplete, it was so massive that a two-volume Latin edition printed in 1486 weighed over 20 pounds.

In answer to charges that he had overindulged in life's pleasures, Rhazes published a book called The conduct of a philosopher. Here Rhazes described himself as a man who had always been moderate in everything except acquiring knowledge and in writing books. He claimed that he worked day and night and damaged his eyes and hands by writing over 20,000 pages in just one year. Nevertheless, Rhazes taught that a middle road between extreme asceticism and overindulgence was the most healthy way of life. Many biographers state that Rhazes became blind near the end of his life, probably as a result of his alchemical experiments. Although his colleagues urged him to undergo surgery to correct his loss of vision, the great physician told them that he was weary of seeing the world and he refused to undergo any medical or surgical treatments. Later biographical accounts, however, generally claimed that Rhazes became blind after his patron al-Mansur had the physician beaten on the head with one of his books for failing to provide proof of his alchemical theories.

After traveling widely and mastering a broad range of subjects, including philosophy, music, poetry, and logic, Rhazes became interested in medicine after a chance encounter with an apothecary in Baghdad. Thus, Rhazes was already over 40 by the time he began to practice medicine, but he soon mastered the art and established a great reputation as a healer. In competition with hundreds of candidates, Rhazes was chosen as physician-in-chief of one of the first major hospitals in Baghdad. Rhazes selected the healthiest location for the hospital by hanging pieces of meat at various sites in order to find the site where there was the least putrefaction. Through his private practice and his supervision of the hospital Rhazes compiled many intriguing case histories. These offer insight into the range of complaints for which his contemporaries consulted physicians, which signs and symptoms the physician thought significant, the kinds of treatment used, the occupations and family background of his patients, and the relationship between patient and physician. Among the discoveries credited to Rhazes are the identification of the guinea worm (Dracunculus medinensis), the recurrent laryngeal nerve, and spina ventosa. According to Rhazes, both physicians and patients were bound by ethical duties. In order to prevent and cure disease, patients were obligated to trust and cooperate with the physician. According to Rhazes, a learned physician and an obedient patient could vanquish illness. Unfortunately, not all patients were obedient and many quacks and impostors claimed to cure diseases.

Rhazes' book A Treatise on Smallpox and Measles has become a landmark in the history of medicine. Smallpox (Variola) is an acute viral disease usually transmitted by airborne droplets. Generally, the virus entered the body through the upper respiratory tract. The characteristics and virulence of the virus have apparently varied over time, but virologists have recognized two forms of smallpox: Variola major, which has a mortality rate of about 30%, and the mild form known as Variola minor, which has a fatality rate of about 1%. A Treatise on Smallpox and Measles provides valuable information about diagnosis, therapy, and concepts of diseases during the Middle Ages. At the time, in keeping with classic tradition, diseases were generally defined in terms of major symptoms, such as fevers, eruptive fevers, diarrheas, and skin lesions. Therefore, Rhazes' treatise on smallpox and measles is a major landmark in establishing the concept of specific disease entities. According to Rhazes, smallpox was essentially a stage in the transition from infancy to adulthood during which the blood fermented like wine. By suggesting that this change was a natural aspect of aging, Rhazes attempted to explain why almost all children contracted the disease. These observations indicate that smallpox was a common, perhaps ubiquitous, childhood disease at the time. Measles, which Rhazes recognized as a separate disease, was caused by very bilious blood. However, Rhazes admitted that even an experienced physician might have trouble distinguishing smallpox from measles. To protect his reputation, the physician should wait until the nature of the illness was obvious before giving his diagnosis. Both smallpox and measles could be described as eruptive fevers, but smallpox was more dangerous and almost invariably left survivors with pockmarks and scarring.

Translated into Latin, Rhazes' book had a profound influence on the treatment of smallpox in Europe into the seventeenth century. According to Rhazes, the physician might lessen the virulence of the disease by proper management at the onset, but once the disease was established the physician should encourage eruption of the pox by rubbing, steaming, purging, and bleeding. For many centuries, physicians accepted the "heat treatment" prescribed by Rhazes and wrapped patients in blankets in order to increase perspiration and promote the eruption of the pox. Various recipes were supposed to remove pockmarks, but the nearly universal presence of smallpox scars suggests that these remedies were useless. By differentiating between smallpox and measles Rhazes provided a paradigmatic case for thinking in terms of specific disease entities.


Further Reading


Hopkins, D. R. Princes and Peasants: Smallpox in History. Chicago: University of Chicago Press, 1983.

Khan, M. S. Islamic Medicine. London: Routledge & Kegan Paul, 1986.

Meyerhof, M. Studies in Medieval Arabic Medicine: Theory and Practice. London: Variorum Reprints, 1984.

Rhazes. A Treatise on the Smallpox and Measles. Translated by W. A. Greenhill. London: Sydenham Society, 1848. Reprint, Medical Classics 4 (1939): 22-84.

Siraisi, N. G. Medieval and Early Renaissance Medicine. Chicago: University of Chicago Press, 1991.


Magner, L. N. "Smallpox: Most Terrible of All the Ministers of Death." International Journal of Dermatology 24 (1985): 466-470.

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