This systematic review evaluated 36 studies that encompassed pharmacy participation in patient rounds and medication reconciliation efforts as well as drug-specific pharmacist services. The authors detail the individual and collective findings, which include reductions in adverse drug events or errors in more than half the trials with improvements in medication adherence, knowledge, and appropriateness in a similar proportion. None of the studies demonstrated a worse overall outcome, and only one suggested increased health care utilization. The authors outline the needs for future investigation around roles for clinical pharmacists, clinical areas and patients most likely to benefit from their services, and better models to determine cost effectiveness.