The study carried out at Percy hospital (Clamart, France) gives a description of nurses' practices for each stage of the drug use process. Their knowledge about drugs risk was also evaluated. Results of this background give an assessment of practices before hospital accreditation and will be used to define the priority actions of improvement. Recent implementation of unit dose drug dispensing system and simplification of adverse drug event report illustrate these actions to enhance safety and to decrease iatrogenic risk. In addition, pharmacists proposed a training for nurses about drug iatrogenic disease.