Pharmaceutical residues, so-called “emerging” or “new” unregulated contaminants, have raised a great deal of interest in recent years due to their potential to cause negative effects in the environment and later in living organisms. There is a high possibility that these compounds may be the reason for the increase in bacterial resistance to antibiotics (D´ıaz-Cruz and Barcelo, 2006; ´ Kim and Carlson, 2005) or disruption of the endocrine system (Vanderford et al., 2003) causing infertility (Liu et al., 2008) and accelerated maturation in females (Coetsier et al., 2006). Furthermore, some pharmaceuticals (especially antidepressants and antibiotics) may be subjected to bioaccumulation processes in aquatic organisms (mostly fish) (Chafer-Perica et al., 2010; Jo et al., 2011). Consumption of pharmaceuticals continuously increases and, furthermore, the introduction rate of such compounds to the environment may exceed the degradation rate, thus in such a case they would be detected worldwide. The exact risks associated with decades of persistent exposure to random com binations of low levels of pharmaceuticals is not yet well recognized (Gracia-Lor et al., 2011). Pharmaceuticals are mainly excreted in unchanged form; however, certain compounds may be at least partially metabolized or degraded in natural conditions to more harmful chemicals (Gros et al., 2006b; Hanysov ˇ a´ et al., 2005) (e.g., transformation of paracetamol; see Figure 1), thus both parent compounds and transformation products should be of concern during analytical research. The environment is exposed to pharmaceuticals derived from the veterinary field, medicine, and agriculture and pharmaceuticals excreted from animals and humans (Fatta-Kassinos et al., 2011). Moreover, additional chemicals are delivered into the environment during the disposal of expired medications (AlOdainia et al., 2010). Many pharmaceuticals cannot be totally removed during the treatment of drinking water (Zwiener, 2007) or during sewage treatment, thus they can be found in the effluents (Kosjek et al., 2007) and later in the environment. In addition, livestock excrement used as fertilizer is sprayed on farm fields, introducing pharmaceutical residues to food and water and later to humans and animals (Jelic et al., 2009; Kasprzyk- ´ Hordern et al., 2007).