During the last few years various important new initiatives have helped enhance the attention paid to patient safety. Healthcare organisations have been increasingly turning to human reliability techniques, such as Failure Mode and Effect Analysis (FMEA), to help them understand how and why errors or failures occur. The aim of the thesis was to explore the use of FMEA within healthcare, in particular its validity and reliability. An extensive literature review regarding the application of FMEA within the healthcare system was first conducted. Following the literature review it was decided to test the reliability of FMEA by recruiting two multidisciplinary teams to conduct the same FMEA, in parallel, in order to compare their results. To explore the validity of FMEA, the team's FMEA results were compared to data collected from observational work, the hospital's incident report database, audits and additional data collected trom the laboratory. In addition to this, a series of interviews conducted with healthcare professionals who have used FMEA around the UK were qualitatively analysed to identify their perceptions and experiences with FMEA. Finally, the use of clinical decision support systems (CDSS) for antibiotics was reviewed to determine whether or not some of the team's recommendations were feasible. The literature review revealed that FMEA is relatively new in healthcare but its use has been supported by a number of patient safety organisations, particularly in the United States. Using a multidisciplinary team to map the process of care resulted in valid and reliable results. However, identifying failures within this process and scoring them accordingly indicated that FMEA's methodology is unreliable and not valid. FMEA results are very subjective and depend upon the specific multidisciplinary team involved. In addition to this, the interviews revealed that while participants thought FMEA was useful to identify potential failures, it was very subjective and lacked evidence for its validity and reliability. Finally the literature review conducted for the use of CDSS and antibiotics revealed that CDSS presents a promising future for optimising antibiotic use, however, it is difficult to generalise its success as most studies were conducted in the United States. In addition to this, the development and implementation of CDSS would require a lot of work, time and costs with no guarantee that its use will be supported by healthcare professionals In conclusion, FMEA is a useful tool to aid multidisciplinary groups in mapping and understanding a process of care. However, it is not a valid or reliable tool for identifying the failures that can occur or scoring their severity, probability and detectability. Healthcare organisations should not solely depend on their FMEA results to ensure patient safety.