Pharmaceuticals and personal care products (PPCPs) have been detected in several aquatic ecosystems during the last two decades, but their potential for biological effects to nontarget organisms is only now being studied. The aim of this study was to compare and rank the cyto-genetic effects induced by 96-hour exposure to an environmental concentration (1 nM) of triclosan (TCS), trimethoprim (TMP), diclofenac (DCF), ibuprofen (IBU), and paracetamol (PCM) on the freshwater bivalve Dreissena polymorpha by integrating biological responses of eight biomarker into a simple biomarker response index (BRI). The application of the BRI decreased the wide biomarker variability and enabled toxicity ranking of the tested PPCPs as follow: TCS > TMP > IBU > DCF = PCM. This approach allowed us to draw an accurate PPCP scale of toxicity of the most dangerous drug and to address further in-depth investigations.