Al-Razi, a 9th century Persian physician, made the first major Muslim contribution to medicine when he developed treatments for smallpox and measles. He also made significant observations about hay fever, kidney stones, and scabies, and first used opium as an anaesthetic. A generation later, Ibn Sina earned his place as one of the greatest physicians in the world, with his most famous book used in European medical schools for centuries. He is credited with discovering the contagious nature of diseases like tuberculosis, which he correctly concluded could be transmitted through the air, and led to the introduction of quarantine as a means of limiting the spread of such infectious diseases. Other Muslim physicians accurately diagnosed the plague, diphtheria, leprosy, rabies, diabetes, gout, epilepsy, and hemophilia long before the rest of the world. In the 10th century, Al-Zahravi first conducted surgery for the eye, ear, and throat, as well as performing amputations and cauterisations. He also invented several surgical instruments, including those for the inner ear, the throat, and the urethra.
Muslims also advanced the field of pharmacology. They experimented with the medical effects of various herbs and other drugs, and familiarised themselves with anaesthetics used in India. There is evidence that some Muslim physicians also adopted the practice of acupuncture from China. Despite many advancements in medicine, however, Muslim physicians still based their work on the idea of the ancient Greek, Galen, that the body was made up of the same four elements as the world in general - earth, air, fire, and water. Contrary to Christian beliefs, Muslim physicians concluded that illness was not due to supernatural forces, but rather to an imbalance in the body's elements, which physicians were able, in many cases, to correct.