Muhammad ibn Zakariya ar-Razi

Abūbakr Mohammad-e Zakariyyā-ye Rāzī ابوبكر محمّد زکرياى رازى
Born	854 CE Ray, Persia
Died	932 or 925 CE Ray, Persia (Iran)
Era	Islamic golden age
Main interests	Medicine, philosophy, alchemy
Notable ideas	The first to produce acids such as sulfuric acid, writing up limited or extensive notes on diseases such as smallpox and chickenpox, a pioneer in ophthalmology, author of the first book on pediatrics, making leading contributions in inorganic and organic chemistry, also the author of several philosophical works.

Abū Bakr Muhammad ibn Zakariyyā al-Rāzī (ابوبكر محمّد زکرياى رازى Abūbakr Mohammad-e Zakariyyā-ye Rāzī, also known by his Latinized name Rhazes or Rasis) (854 CE – 925 CE), was a Persianpolymath, physician, alchemist, philosopher, and important figure in the history of medicine.

A comprehensive thinker, Razi made fundamental and enduring contributions to various fields, which he recorded in over 200 manuscripts, and is particularly remembered for numerous advances in medicine through his observations and discoveries. An early proponent of experimental medicine, he became a successful doctor, and served as chief physician of Baghdad and Ray hospitals. As a teacher of medicine, he attracted students of all backgrounds and interests and was said to be compassionate and devoted to the service of his patients, whether rich or poor.

According to the Encyclopædia Britannica (1911), he was among the first to use humoral theory to distinguish one contagious disease from another, and wrote a pioneering book about smallpox and measles providing clinical characterization of the diseases. He also discovered numerous compounds and chemicals including alcohol and kerosene, among others.