Physician; worked 4th century BC
Information on the life of Diocles is scarce. It is known that he was born in Carystus (Euboa) and worked in Athens, where he wrote the first medical treatise in the local Greek dialect (Attic; all previous works had been written in the Ionic Greek dialect, an indication of the early intellectual importance of Ionia). Only few fragments of his works survived, but he must have been held in high regard. The Roman author Pliny said that Diocles was "both in time and reputation next and second to Hippocrates."
Diocles studied animal anatomy through dissection and wrote his findings down in a textbook, the first systematic work on the subject in Europe. It appears that he also wrote textbooks based on the Hippocratic Collection that cover a wide range of topics including anatomy, physiology, pathology, therapeutics, embryology, sexuality, gynaecology, dietetics, poisons and foods such as wines, herbs, vegetables and olive oil. Other topics cover the role of mineralogy and meteorology in medical treatment. His major influence, however, was on the level of practical medicine, where he was innovative and showed new directions.
For a time it was believed that Diocles was a contemporary of Plato. It is now accepted that he lived somewhat later, around the time of Aristotle. This is suggested by his terminology and methodology, which shows Aristotelian influence. Some believe that he was a student of the Lyceum.
Note: Some sources confuse the physician Diocles of Carystus with the mathematician Diocles of Alexandria, who lived in the 2nd century BC.