The complexity of the health care environments necessitates an holistic and systematic ergonomics approach to understand the potential for accidents and errors to occur. The health service is also a socio-technical system, and design needs must be met within this context. This paper aims to present the design challenges and emphasises the specialised needs of the health care sector, when dealing with patient safety. It also provides examples of approaches and methods that ergonomists can bring to help inform our knowledge of these systems and the potential towards improving their safety. Mapping workshops provide an example of such methods. Results from these are used to illustrate how the knowledge base required for better design requirements can be generated. The workshops were developed specifically to help improve the design of medication packaging and thereby reduce the probability of medication error. The issues raised are now the subject of further research, design requirements guidance and new design concepts. The paper illustrates the need to engage with the design community and, through the use of robust scientific methods, to generate appropriate design requirements.