Persia has a long history of studying and practicing the medicine. This is devided into three eras: three ancient, medieval, and modern period. During the 6th BC, the Avesta book was written which is considered as the earliest texts in Persian language that discusses about diseases. The law against demons (Vendidad) text, remained by Avesta, written in the Arsacid period (ca. 200 BC). In the Vendidad, the most important reason of sickness was the consequence of demonic forces.

Ancient Persians considered that illness will be caused by supernatural forces and evil spirits. In those eras, the most respected healers were those who treated patients with holy words and improve their physical health accordingly. This group was called Mantsara Pezeshk (a healer who can treat a sick person with holy words).

The first period of the of Persian medicine growth began in the middle of the first millennium BC and reached its peak when most of the region was under the influence of the Persian Empire. The word Deev in Sanskrit language means God. After the appearance of Zarathushtra, some of the former Aryan gods who were not accepted by the new religion were separated from other gods under the title of demon. In this way, the word crazy (Deevane in Persian) was gradually applied to mental patients with abnormal behavior states, which indicated a special group of abnormal beings.