Aretaeus of Cappadocia writes in Ionic Greek a general treatise on diseases, which is still extant, and is certainly one of the most valuable relics of antiquity.

The book displays great accuracy in the detail of symptoms, and in seizing the diagnostic character of diseases.

In his practice he follows for the most part the method of Hippocrates, but he pays less attention to what have been styled "the natural actions" of the system; and, contrary to the practice of the Father of Medicine, he does not hesitate to attempt to counteract them, when they appear to him to be injurious.

One disease he describes is later known as Celiac Disease and is common in the world today.

The account which he gives of his treatment of various diseases indicates a simple and sagacious system, and one of more energy than that of the professed Methodici.

Thus he freely administers active purgatives; he does not object to narcotics; he is much less averse to bleeding; and upon the whole his Materia Medica is both ample and efficient.

It may be asserted generally that there are few of the ancient physicians, since the time of Hippocrates, who appear to have been less biased by attachment to any peculiar set of opinions, and whose account of the phenomena and treatment of disease has better stood the test of subsequent experience.

Aretaeus is placed by some writers among the Pneumatici because he maintained the doctrines which are peculiar to this sect; other systematic writers, however, think that he is better entitled to be placed with the Eclectics.

Aretaeus' work consists of eight books, two De causis et signis acutorum morborum, two De causis et signis diuturnorum morborum, two De curatione acutorum morborum, and two De curatione diuturnorum morborum.

They are in a tolerably complete state of preservation, though a few chapters are lost. (See Aretaeus' complete works in Greek and English (edition of Francis Adams, 1856) at the Digital Hippocrates project.)