Ionic liquids are remarkable chemical compounds, which find applications in many areas of modern science. Because of their highly tunable nature and exceptional properties, ionic liquids have become essential players in the fields of synthesis and catalysis, extraction, electrochemistry, analytics, biotechnology, etc. Apart from physical and chemical features of ionic liquids, their high biological activity has been attracting significant attention from biochemists, ecologists, and medical scientists. This Review is dedicated to biological activities of ionic liquids, with a special emphasis on their potential employment in pharmaceutics and medicine. The accumulated data on the biological activity of ionic liquids, including their antimicrobial and cytotoxic properties, are discussed in view of possible applications in drug synthesis and drug delivery systems. Dedicated attention is given to a novel active pharmaceutical ingredient-ionic liquid (API-IL) concept, which suggests using traditional drugs in the form of ionic liquid species. The main aim of this Review is to attract a broad audience of chemical, biological, and medical scientists to study advantages of ionic liquid pharmaceutics. Overall, the discussed data highlight the importance of the research direction defined as “Ioliomics”, studies of ions in liquids in modern chemistry, biology, and medicine.

Organometallic reagents and metal catalysts are used ubiquitously in academia and industry. Not surprisingly, the biological activity and environmental danger of metal compounds have become topics of outstanding importance. In spite of the rapid development of toxicology during the last decades, several common historically established “beliefs” are still frequently circulating in the organometallic community. In this Tutorial, we discuss existing opinions concerning (1) possibilities of toxicity measurements, (2) high toxicities of heavy-metal compounds, (3) correlation between the structure of a metal compound and its toxicity, (4) biological effect of direct/indirect contacts with metal compounds, and (5) dangers of metal nanoparticles. Basic concepts of toxicity studies and known data are described in the Tutorial step by step upon discussion of these issues. The main goal of this Tutorial is to demonstrate that the toxicity of a metal cannot be regarded as a constant property, since it depends on the oxidation state, ligands, solubility, morphology of particles, properties of the environment, and several other factors. As far as such chemically labile species as metal compounds are concerned, the nature of biological effects should not be assumed or taken for granted; indeed, reliable conclusions cannot be made without dedicated measurements.