AbstractIn the present paper we determined the presence of sibutramine in urine using the GCMS/MS system. The determination of sibutramine was studied in relation to slimming healthfoods1. Prolonged or excessive consumption of unauthorized pharmaceuticals may causeserious adverse consequences on health. In this study, samples were extracted with the help ofmethanol and acetonitryl and the sibutramine concentrations were found in the range of 0,5 g/l