Aging is accompanied by intensification of oxidative degradation of proteins, including lipoproteins, proteolytic system dysfunction and accumulation of oxidized proteins. Similar changes are found in drug addiction. In this regard, we carried out a comparative study of conformational changes of plasma proteins and red blood cells of people of different age groups and people who use drugs. The study was carried out with the use of fluorescence analysis to measure the spectra of fluorescence of amino acid residues in proteins (summary fluorescence and tryptophan). In the analysis of fluorescence spectra it is preferable to use the second derivative of the fluorescence spectra as it is the most informative. The application of this research method was chosen because it has high sensitivity. It provides information on the status of living systems without damaging them; it requires large quantities of biological material; it makes it possible to differentiate between the various stages of the disease. Changes in the general phase and tryptophan fluorescence plasma proteins in older people and drug addicts indicate increase in the availability of tryptophan residues to the aqueous environment as a result of conformational changes of macromolecules and the disruption of the lipid layer due to the intensification of free radical processes.