| The system of Iranian medicine in the Qajar era was the continuation of the system based on the humors view. Accordingly, the incidence of most diseases was attributed to whole view of the quadruple imbalance of blood, soda, bile, phlegm. Preventive and therapeutic approaches were also carried out in the same cognitive atmosphere. The example of Smallpox disease, indicates such a view in the Qajar era. According to the findings of this research, in Qajar medical literature, the bumps of pus in the skin of is described to be hard, single or non-separated with different colors and was called as Jodri or Smallpox. In terms of cognitive aspects, physicians of Qajar era following former physicians classified Smallpox disease in terms of humor among the hot and wet diseases and described boiling of blood in the body as the cause of this disease. Exposure to this disease was through the two pathways preventive and |