Fluorometry of histamine and serotonin in cadaveric blood revealed a threefold increase of their concentrations in comparison with those in whole blood of live subjects. This indicates liberation of amines in the course of death and after it when factors inactivating them cease to function. However, the authors consider it possible to validate their conclusions about changes in the content of histamine and serotonin in cadaveric tissues in different diseases, provided certain conditions of selecting the material are adhered to. The distribution of amines in the viscera is not sex-dependent, little depends on the blood content of tissues, and is determined by the organ-specific features of metabolism of these bioactive substances. To illustrate this, the authors consider the content of histamine and serotonin in the organs of patients dead from hemorrhagic fever with the renal syndrome.