The Emergency Department (ED) is a unique environment in medicine, and many safety mechanisms used in other hospital settings cannot be applied in the ED. For example, clinical pharmacists have traditionally provided extra layers of protection to hospital inpatients by cross-checking provider orders for appropriate dosing, contraindications, and interactions. Because medications in the ED must be accessed immediately and are often one-time doses, the use of central pharmacy services would introduce an unacceptable delay to the administration of medication. Although some hospitals have programs in place in which a pharmacist responds to the ED for cardiac arrests or trauma team activations, few have reported programs which involve a clinical pharmacist assigned exclusively to the emergency department. Nonetheless, published reports have asserted that ED-based pharmacists can increase patient safety. Although this concept appears logical, no study has attempted to show that these programs reduce potential adverse drug events in the ED. We propose to implement and optimize an ED Pharmacist (EDP) program as a safe practice intervention in a large ED. The hospital has provided funding for two permanent full time positions starting at the beginning of the award period. In the initial phase interviews of physicians, nurses, pharmacists, and patients will be conducted and the results will be used to optimize the EDP role. A large-scale chart review study will then be conducted to evaluate whether there is a reduction in frequency of potential and adverse drug events during times that the EDP is on duty. Staff perceptions of the effectiveness of this program will also be evaluated. The overall goal of this initiative is to create an effective EDP program that will decrease the rate of adverse drug events in ED patients, and to create a "toolkit" to facilitate the introduction of similar programs into other EDs. This toolkit will include a description of the formal, optimized role of the EDP, challenges and solutions in implementation, and evidence to support the efficacy of such a program.