The first quarter of the twenty-first century has seen a rapid expansion of research into the medical applications of boron cluster-based compounds. Key areas of this research include the use of polyhedral boron hydrides (carboranes, boranes, and metallacarboranes) as pharmacophore groups in the synthesis of compounds with various types of biological activity, the synthesis of boron-rich compounds for boron neutron capture cancer therapy, and the use of boron clusters as carriers of radiohalogen label in radionuclide diagnostics and therapy. This is an attempt to demonstrate the diversity of research being conducted and to briefly touch upon the most interesting results obtained in this area.