Eight Books of Dioscorides in Greek and Latin

From Galen in the work on the power of simple medicines.

Dioscorides of Anazarbus has written of all useful material in his books, not only regarding herbs, but also trees, fruits, juices, and gums; further, he has recorded all matters pertaining to minerals and the parts of animals. It seems to me that he has produced the most complete treatise of all on the material of medicines. While much has been written well by those who came before him regarding these things, no one has written so well concerning them all.

From Oribasius in the 15th book of the Medical Collections.

The knowledge of simple medicines and the powers contained within them is so necessary that it is not even possible to practice medicine correctly without it. For it is simultaneously a resource that is easily found in every circumstance of the times, and this knowledge is useful for evaluating the powers of compound medicines. Furthermore, it is useful for discovering them; in general, the knowledge of this displays technical skill to all.

Concerning this Dioscorides, as some suppose.

From the Suda A massive 10th-century Byzantine encyclopedia..

Dioscorides of Anazarbus, a physician, was surnamed Phacas, because of the lentils phakoi lentils/freckles on his face. He was with Cleopatra in the time of Antony, and twenty-eight medical books are attributed to him, all of which are renowned.