Muhammad ibn Zakariy? R?z蘋 (Mohammad-e Zakari?-ye R?zi: Persian: ?堶?堹 堬琠堭?塈? 堭塈堬?), known as Rhazes or Rasis after medieval Latinists, (August 26, 865 ??925) was a Persian polymath, physician, alchemist and chemist, philosopher, and scholar.

Numerous 'firsts' in medical research, clinical care, and chemistry are attributed to him, including being the first to differentiate smallpox from measles, and the discovery of numerous compounds and chemicals including kerosene, among others.

Razi made fundamental and enduring contributions to the fields of medicine, alchemy, music, and philosophy, recorded in over 200 books and articles in various fields of science. He was well-versed in Persian, Greek and Indian medical knowledge and made numerous advances in medicine through his own observations and discoveries.

Educated in music, mathematics, philosophy, and metaphysics, he chose medicine as his professional field. As a physician, he was an early proponent of experimental medicine and has been described as the father of pediatrics. He was also a pioneer of ophthalmology. He was among the first to use Humoralism to distinguish one contagious disease from another. In particular, Razi was the first physician to distinguish between smallpox and measles through his clinical characterization of the two diseases.