The Unani System is based on the humoral theory, i.e. the presence of blood, phlegm, yellow bile and black bile in every person. The temperament of a person can accordingly be Sanguine, Phlegmatic, Choleric and Melancholic depending on the presence and combination of the Humors. According to Unani theory,the humors and the drugs themselves are assigned temperaments. Any change in quantity and quality of the humors brings about a change in the status of the health of the human body. A proper balance of humors required for the maintenance of health.