“See and Treat” in an Emergency Department combines the process of patient assessment with treatment in the expectation that it will increase patient throughput and decrease queuing. This paper describes an evaluation of the flow of minor emergencies in an Emergency Department in the UK that had partially implemented “See and Treat” and was planning to reorganize the department yet again to reseparate the activities of assessment and treatment. A discrete event simulation indicated that the proposed system in which “See” and “Treat” were separated improved patient throughput and was likely to be more cost-effective. There were difficulties in obtaining credible data for the analysis, though this was mitigated by using the same distributions, for the analysis of both of the systems. With increasing pressure to introduce industrial concepts, such as Lean, to the health sector, simulation provides a means of assessing expensive and disruptive changes before implementation...