The idea of pollution, probably posthomeric, was already widely accepted by the 7th century B.C. It developed gradually both in parallel with the cult of the shades of the dead and the chthonian deities. According to it, any person guilty of manslaughter was unclean, and his stain brought down the wrath of the gods upon the whole community he belonged to. For the Erinyes to be satisfied, the guilty man had to submit himself to purification. Pollution was removed by cleansing, the ritual for which, although different in each case, always had as its aim to propitiate the gods. Either because it was more closely connected with the Orient or because older traditions survived there, Crete was famous for magicians and prophets specializing in cleansings. Even Apollo himself was cleansed, after killing the Python, by the Cretan Carmanor. Later, indeed, cleansings became a matter about which the oracle was the best adviser. When Athens had to be cleansed from the curse (agos) of Cylon, the Pythia advised that the prophet and priest Epimenides be summoned from Crete. In another case, Delphi gave instructions to Pythagoras tyrant of Ephesus that the city be rid of a pollution that was causing a plague. Sparta, too, had earlier had recourse to the assistance of Thales of Gortyn to rid herself of a plague. Onomacritus the Locrian is named by Aristotle as the teacher ot Thales. Diotima, the witch from Mantinea is said to have saved many from the great plague at Athens at the start of the Peloponnesian war, by suggesting sacrifices. Lastly, it is well known that after Pausanias' death the Lacedaemonians asked that their city be cleansed by necromancers from Phygalea.

The view of prophet-healers as peripatetic is dated to earlier ages. These properties were ascribed to various gods and heroes by the mythological tradition that took shape from the end of the Mycenaean world to the time of Hesiod. In Thessaly these traditions apparently had deep roots that led to the centaur Chiron, teacher of Achilles in healing. Tricce (Trikala) was regarded as the most ancient site of the cult of Asclepius. Archaeological research may have located the shrine, but as yet it has been unable to verify its antiquity. Machaon and Podalirius, the sons of Asclepius, were the doctors of the Hellenes at Troy. Indeed, a rudimentary specialization was already attainable, apparently, as Machaon specialized in pathology and Machaon in surgery. The latter had four sons, all doctors, one of whom was Alexanor, founder of the second oldest Asclepieum (the first in southern Hellas), at Titane in Sicyonia. At Epidaurus the cult of Asclepius arrived comparatively late. But another local mythical healer figure was already there and had a cult: Maleatas.

The descendants of Podalirius settled at Cos and practised healing, always transmitting their skills from generation to generation. The most celebrated member of this family, who were called the Asclepiadae, was Hippocrates. The healing families continued to specialize in the traditions of the prophet families, with severely intraspecific transmission of knowledge. The maintenance of this canon was, indeed, secured with an oath sworn to the Hippocratidae, just had been usual with the Babylonian mages and the Chaldean astronomers.

Healing skills had already started to be systematized even before Hippocrates. One of the most important doctors at the end of the Archaic period was Democides of Croton. Taken prisoner by Darius as a member of the court of Polycrates of Samos, he managed to get himself appointed personal doctor to the queen Atossa. After winning her trust by spectacular therapies, he was freed with her help. It was at the same period that the healer Alcmaeon was active: he too came from Croton.