Professionals and researchers have developed a number of strategies aimed at improving the quality and safety of medication use. However, studies continue to demonstrate persistent problems. For instance, the first paper in this thesis reveals the prevalence of potentially harmful drug combinations among elderly people in Europe. The following four papers focus on two professional groups and how they have approached safety and quality issues related to medication use: 1) the Swedish drug and therapeutics committees (DTCs) and 2) pharmacist involved in pharmaceutical care, an international movement. Qualitative research approaches were applied. Papers II and III focus on the DTCs: analyses indicate a development of the perception of the DTC role over time. The focus of the activities was broadened – from targeting prescribing physicians to incorporating decision-makers and patients. However, a clear patient-centered perspective was generally lacking. Moreover, the findings indicate a shift in focus from cost aspects of medication use to an increased focus on quality and safety aspects. In the studies addressing pharmaceutical care (Papers IV and V), the findings propose that different classification systems for drug-related problems had different characteristics which reflected differences in goals in the pharmaceutical care process. It was also found that the concept of pharmaceutical care was understood in different ways and that the perceptions were based on at least two different understandings of health and illness. First, a patient-centered perspective characterized by a holistic understanding of health and illness, and, second, an “EBM perspective” primarily based on a biomedical understanding of health and illness. This thesis has disclosed new aspects of how two groups of professionals perceive their work towards improved quality and safety of medication use. A patient-centered perspective among healthcare collectives is not obvious; therefore, efforts and comprehensive strategies supporting change are necessary. Strategies should focus on challenging the traditional thought patterns and care approaches among professionals and students