In this study, pharmaceutically active compounds (PhACs) were analyzed in the influent and effluent of a domestic wastewater treatment plant in Turkey and a municipal wastewater treatment plant in Germany and the toxicity of these wastewaters were estimated using a toxic unit (TU) approach. A total of 21 and 32 PhACs were detected in the domestic wastewater and the municipal wastewater, respectively. The TUs estimated for PhACs in municipal wastewater were higher than the TUs estimated for PhACs present in domestic wastewater. The levels of the anti-anxiety drug, oxazepam were estimated to be in the high risk category (HQ>10) in both wastewaters. In bench-scale tests with ozonation, the removals of four PhACs in the municipal wastewater were investigated. At a dose of 2mg/L ozone, 97%-98% of diclofenac and carbamazepine were removed. The lowest removal rate at 71% was observed for metoprolol.