The article discusses the possibility of developing a combination of drugs for the treatment of atherosclerosis in elderly patients. Atherosclerosis is a multifocal pathology that leads to disease duration and reduces the patient's quality of life, resulting in a need to provide a rational pharmacotherapeutic geriatric care. The similarity theory is proposed as a basis for selection of an active ingredient derived from medicinal plants. This theory evolved gradually, and various scientists developed and complemented it for many centuries. The analogy lies in the basis of the similarity theory. Similarity between objects of different nature was marked way back by ancient philosophers. Later on, based on the acquired and transferred knowledge, other scientists formed the theory of similarity as a method of physical modeling. The special contribution to its development was made by such thinkers and scientists as Democritus, Aristotle, Plato, I. Newton, M.V. Lomonosov, V.L. Kirpichov and others. The basic tenets of the similarity theorem include: similar phenomena have the same similarity criteria; the functional relationship between the quantities characterizing the process can be represented as the relationship between them made up of similarity criteria; sufficient similarity between the two systems is the equality of any two corresponding similarity criteria of the systems composed of their main parameters and initial (boundary) conditions. In view of these tenets, there was formulated a working hypothesis: substances similar in their chemical structure and containing the same functional groups have similar properties. This in turn allows to determine the class of biologically active substances which will have a lipid-lowering effect. In this regard, the authors propose a number of medicinal plants, such as Asteraceae, Fabaceae, Rosaceae, whose biologically active complexes are structurally similar to the structure of statins – the most commonly used drug substances for the treatment of this pathology.