Herophilos, sometimes Latinized Herophilus (335-280 BC), was a Greek physician. He was born in Chalcedon in Asia Minor (now Kadiköy, Turkey). Together with Erasistratus he is regarded as a founder of the great medical school of Alexandria. He was the first to base his conclusions on dissection of the human body. He studied the brain, recognizing it as the center of the nervous system and the site of intelligence. He also paid particular attention to the nervous system, distinguishing nerves from blood vessels and the motor from the sensory nerves. Other areas of his anatomical study include the eye, liver, pancreas, and the alimentary tract, as well as the salivary and genitalia. His works were lost but were much quoted by Galen in the 2nd century AD. Celsus in 'De Medicina' and the church leader Tertullian state that he vivisected at least 600 live prisoners (although it should be noted that Tertullian lived several centuries after Herophilos and may have had reasons to discredit what he saw as heresy).

Among the first scientists Herophilos is thought to be one of the founders of the scientific method. He had introduced the experimental method to medicine, for he considered it essential to found knowledge on empirical bases. For that he was criticized by Galen for whom the experimental method contradicted rationality. Herophilus had also introduced many of the scientific terms used to this day to describe anatomical phenomena. He was among the first to introduce the notion of conventional terminology, as opposed to use of "natural names", using terms he created to describe the objects of study, naming them for the first time. A part of the skull torcular Herophili is named after him.

Another figure by this name (Herophilus) was an impostor in the time of Julius Caesar who pretended to be the grandson of Gaius Marius. Caesar banished him.

See also

• Timeline of medicine and medical technology