Selected issues related to the toxicity of ionic liquids and deep eutectic solvents—a review

Green Chemistry plays a more and more important role in implementing rules of sustainable development to prevent environmental pollution caused by technological processes, while simultaneously increasing the production yield. Ionic liquids (ILs) and deep eutectic solvents (DESs) constitute a very broad group of substances. Apart from many imperfections, ILs and DESs have been the most promising discoveries in the world of Green Chemistry in recent years. The main advantage of ILs is their unique physicochemical properties—they are very desirable from the technological point of view, but apart from these benefits, ILs appear to be highly toxic towards organisms from different trophic levels. DES areas of usage are very spread, because they cover organic synthesis, extraction processes, electrochemistry, enzymatic reactions and many others. Moreover, DESs seem to be a less toxic alternative to ionic liquids. New possibilities of applications and future development trends are sought and presented, including such important solutions of life branches as pharmaceuticals’ production and medicine.