The review discusses the interchangeability of medications, approaches to the registration of original and generic drugs, and types of their equivalence, as well as problems with generics in clinical practice. Results of pharmacoepidemiological studies, which have been widely carried out recently, speak of insufficient understanding of the impact of generics on remote outcomes of chronic diseases, including mortality. The long-term economic prospects of generic drug administration continue to remain unclear. Among the primary differences between generics and brand-name drugs are the differences in active ingredient synthesis methods and the composition of adjuvants and additives. Comparative studies on the therapeutic equivalence of generics with their originals or between themselves are rarely conducted. They are often affected by methodological flaws, which cannot ensure their comparable efficacy and safety. In this regard, automatic replacement of drugs containing the same active ingredient should be avoided without the participation of the attending physician. © 2021 Ima-Press Publishing House. All rights reserved.