Pharmacy departments are technical and administrative units in hospitals that relate to several other departments, and thus they have a strategic status on supervising the medication system. The hospital pharmacy department has an important role on patient safety, as it can work on error prevention, avoiding mistakes on the process. If there are no precautions implemented on medication system, there will be greater risk of errors, which could unavoidably harm the patient's health. In this context, this article reports a research applied on a psychiatric hospital in the state of Santa Catarina, Brazil. The following issue was the starting point of the research: how is the configuration of the medication system in this hospital? The objective was to analyze the system, through mapping, in order to identify strategic opportunities for design. Results demonstrate that the medication system is integrated to the pharmacy, and depends on it. Results also suggests that strategic design interventions on storage, fractionation, separation and dispensation of drugs could contribute to the safety of the system as a whole.