Human Factors (HF) methods are increasingly needed to support the design of new technologies in order to avoid that introducing those technologies into healthcare work systems induces use errors with potentially catastrophic consequences for the patients. This chapter illustrates the application of HF methods in developing two health technologies aiming at securing the hospital medication management process. Lessons learned from this project highlight the importance of (i) analyzing the work system in which the technology is intended to be implemented, (ii) involving end users in the design process and (iii) the intermediation role of HF between end users and scientific/technical experts.