Abu Bakr Mohammad Ibn Zakariya al-Razi (ابو بکر محمد ابن زکریا الرازی) born on 28 August 865 and died on 6 October 925 in (the Persian Empire, now Iran (Ray near Tehran. Razi achieved mastery in a number of fields, initially, he was interested in music but later on he learnt medicine, mathematics, astronomy, chemistry and philosophy from a student of Hunayn Ibn Ishaq (حنین ابن اسحاق) , who was well versed in the ancient Greek, Persian and Sub-Continent systems of medicine and in other subjects. He also studied under Ali Ibn Rabban(علی ابن ربان) .

Around the age of thirty he was first placed in-charge of the first Royal Hospital at Ray, from where he left for Baghdad (now in Iraq), where he was active in the reconstruction of the city hospital, where he remained the head of its famous Muqtadari Hospital for along time.. Al-Razi became famous as the most prominent physician in the Islamic world, his fame comparable only to that of another Persian physician, Ibn Sina. The practical experience gained at the well-known Muqtadari Hospital helped him in his chosen profession of medicine. At an early age he gained eminence as an expert in medicine and alchemy, so that patients and students flocked to him from distant parts of Asia.

Razi was a Hakim, an alchemist and a philosopher. In medicine, his contribution was so significant that it can only be compared to that of Ibn Sina. Some of his written works in medicine have been widely studied, Latin editions of which remained in use as late as the seventeenth century in Europe, e.g. Kitab al- Mansoori (کتاب المنصوری), Al-Hawi (الحاوی), Kitab al-Mulooki (کتاب الملوکی)and Kitab al-Judari wa al- Hasabah(کتاب الجزداری و حسابہ) earned everlasting fame. Kitab al-Mansoori(کتاب المنصوری) , which was translated into Latin in the 15th century C.E., comprised ten volumes and dealt exhaustively with Greco-Arab medicine(ادویات العربیہ و یونانیہ) . From him we have the earliest distinction between smallpox and measles, and the understanding that smallpox occurs only once in a person's life. As a skilled chemist he recognized the toxicity of arsenic (arsenic oxide), but prescribed small doses of this compound in the treatment of many skin diseases and anemia.

He was a prolific author, who has left monumental treatises on numerous subjects. He has more than 200 outstanding scientific contributions to his credit, out of which about half deal with medicine and 21 concern alchemy. He also wrote on physics, mathematics, astronomy and optics, but these writings could not be preserved. A number of his books, including Jami-fi-al-Tib , Mansoori (کتاب المنصوری), al-Hawi(الحاوی) , Kitab al-Jadari wa al-Hasabah(کتاب الجزداری و حسابہ), al-Malooki (کتاب الملوکی) , Maqalah fi al- Hasat fi Kuli wa al-Mathana (مقالہ فی الکلی و المتحانہ), Kitab al-Qalb (کتاب القالب), Kitab al-Mafasil (کتاب المفاصیل), Kitab-al- 'Ilaj al-Ghoraba (کتاب العلاج الغربا), Bar al-Sa'ah (بارالصابا), and al-Taqseem wa al-Takhsir (التقسیم و التخسیر), have been published in various European languages. About 40 of his manuscripts are still extant in the museums and libraries of Iran, Paris, Britain, Rampur, and Bankipur. His contribution has greatly influenced the development of science, in general, and medicine, in particular.

Like his predecessor, the Arabian alchemist Jabir ibn Hayyan (جابر بن حیّان), al-Razi was influenced in his alchemical views by Aristotle's theory of the four elements. Arabic alchemists had modified the Aristotelian system with respect to the composition of minerals, whereby two elements, mercury and sulfur, were responsible for "the mercurial and sulfurous principles" of a given substance. Later called "philosophical" Mercury and Sulfur, these elements (or principles) were thought to be the substances from which all metals were formed. This Sulfur-Mercury theory later became highly influential among European thinkers, for example, Isaac Newton. To this Sulfur and Mercury, al-Razi added a third constituent, a salty principle (which was later reproposed by Paracelsus). In al-Razi's opinion metals were comprised of particles of these elemental constituents, while the identity of the metal depended on the relationships between these indivisible particles and the empty spaces between them.

In contrast to Jabir, who inclined toward numerical mysticism, al-Razi became practiced in experimental work. This is apparent from his two most influential works, Kitab al-Asrar (کتاب الاسرارThe Book of Secrets ), and Kitab sirr al-Asrar (کتاب سرالاسرار -The Book of the Secret of Secrets ). In these works he gave several recipes for the alleged transmutation of common metals into precious ones, and crystal or glass into precious stones. Perhaps al-Razi's main contribution to chemistry was his attempt to systematize laboratory practices, to which end he listed contemporary laboratory equipment and techniques used in chemical experiments. Another influential contribution to chemistry was his classification of all the chemical substances he knew, for this is the earliest attempt of which we are aware. Al-Razi divided these substances into four main groups: vegetable, animal, derivative, and mineral. The last group consisted of six subgroups: (1) spirits (volatile substances, such as mercury, sulfur, and arsenic sulfide); (2) metals (gold, silver, copper, tin, iron, lead, and "karesin," probably a bronze composed of copper, zinc, and nickel); (3) stones (ores and minerals of iron, copper, zinc, but also glass); (4) atraments (metallic sulfates and their derivatives); (5) boraces (borax, but also sodium carbonate [confused with borax]); and (6) salts (in which categorization sodium chloride appears under four different terms, other salts being sodium carbonate, potassium carbonate, and others).

In later life al-Razi became blind, which, according to some sources, was a result of his indefatigable activity—for he is said to have written approximately 200 works. He finally returned to Ray, where he died around 930 C.E. His name is commemorated in the Razi Institute near Tehran.

Community content is available under CC-BY-SA unless otherwise noted.