Ar-Razi was a pioneer in many areas of medicine and treatment and the health sciences. He was a pioneer in the fields of pediatrics, obstetrics, and ophthalmology. He had the greatest position of scientist in Islam and The Medieval ages and could only be compared with Ibn Sina. He greatly favored cure through correct and regulated foods. His writings on small pox and measles show originality and accuracy and his essay on infectious diseases was the first scientific treatise on the subject. He was the first person to use alcohol for medical purposes. He was a pioneer in health science, pedriatics, obstetrics, and opthamology. He wrote the description about the spinal cord. He was an expert surgeon. He was first to give an account of operations for the extractions of the cataract and first to discuss pupilary reactions.. He wrote a number of books including Al-Hawi (Comprehensive book) which contains Greek Syrian, and early Arabic medical knowledge. It was the largest medical encyclopedia. He wrote a chapter on anatomy in Kitab al-Mansuri. Al-Judari-wa-al Hasabah contains the first treatise on small pox and chicken pox. He was the first person to note the differences between chicken pox and small pox. He made more then 200 scientific contributions in which on half of them are about medicine, 21 are on chemistry and the rest are on physics, mathematics and astronomy.