In the course of a clinical study in 1989, a connection between drug interactions and grapefruit juice was observed accidentally. Further studies concluded that this interaction could be due to the presence of flavanones.Flavanones, a subgroup of flavanoids, show chirality and they exist in two enantiomeric forms.The majority of drugs is metabolised by Cytochrom P450 enzymes. Since it is already known that a great number of enzyme interactions are stereospecific, an extensive knowledge about the pharmacokinetic features of flavanones and the associated interactions are of great significance. An important approach to gain more precise insight into these pharmaceutical interactions is the separation of enantiomers. For the purpose of this diploma thesis, the enantiomers of the flavanones naringin, naringenin, alpinetin und pinocembrin were separated by HPLC. Furthermore, the occurance of flavanones was examined by means of reversed-phase HPLC, using a diode array detector. Under normal phase conditions the enantiomers were separated by HPLC-analysis with a Chiralcel OD column and a UV-detector. From an extract of elderflowers, it was possible to detect naringenin. The results of the subsequently conducted enantiomeric separation showed higher proportion of the R-enantiomer.Using an open column chromatography and semipreparative HPLC-analysis, alpinetin and pinocembrin were isolated from an extract of the seeds of Alpinia katsumadai which is primarily used in TCM. By determining the optical rotation, it was possible to allocate the enantiomers to the results of the HPLC-UV analysis. The investigation demonstrated that the amount of R-enantiomers prevails in both, alpinetin and pinocembrin. To separate the enantiomeres of naringin, the albedo layers of grapefruits and pomelos were used as sample materials. In this case, the proportion of R- and S-enantiomers was equal, accordingly naringin occured as racemate.