Histidine dipeptides and their derivatives have a significant role in a variety of physiological and pathological processes. Thus, the authors discuss the available analytical methods for the determination of various bioactive histidine dipeptides and their derivatives, their advantages and disadvantages, as well as their specific applications. The authors propose that the investigation of the structure of peptides is of fundamental importance as a first step to understanding their role in the mechanisms of the formation and biochemical functions of proteins. The biological activities of selected natural di- and tripeptides are discussed, as well as their applications in the food industry. Currently, research is continuing to identify new sources of bioactive peptides, as well as methods of their preparation, bioavailability, biological activity and mechanisms of action. The closing review summarises the literature data and the results of experiments on the effect of small regulatory peptides (which are fragments of many natural compounds such as collagen and neurohormones) on the state of aggregation of blood cells.