EN
Many Western scholars have researched Thomas Sydenham’s profile as a reformer of classiv humoral pathology standard and described his achievements in the field of medicine. I have discussed his achievements in my earlier works (1990-2016). I would like to describe the genesis of Sydenham’s modification of classic humoral pathology standard in this paper. Furthermore, I would like to explain the author’s reasoning according to medical knowledge of the era and to schow reasons of „epidemic constitution” conception popularity in European modern medicine. I would like do discuss also reasons of its popularity decline among the clinicians which took place gradually even before widerspread acceptance of clinical standard of bacteriology in medicine.