Ionic liquids are new solvents showing unique physical-chemical properties. They are characterized by a wide range of temperatures, in which they are in a liquid form and where they exhibit high thermal stability. They are able to dissolve organic and inorganic substances as well as some polymers. They are a ‘green’ alternative to conventional solvents as their vapour pressure is very low even at a raised temperature and under a decreased pressure, and because it is possible to use them multiple times through recycling. Ionic liquids are mainly used in extraction processes from both the aqueous phase and the more complex mixtures such as food products. In many cases, the extraction from an aqueous phase consists solely in replacing an organic solvent by a ionic liquid, whereas the extraction from food samples requires that those samples are pre-treated, e.g. through etching. Ionic liquids are successfully applied to extracting metal ions, carboxylic acids, colourants, pesticides, and biologically active substances from medicinal plants.