Stem cells offer tremendous promise for advancing health and medicine. Whether being used to replace damaged cells and organs or supporting the body’s intrinsic repair mechanisms, stem cells hold potential to treat such debilitating conditions as Parkinson’s disease, diabetes, and spinal cord injury. Though clinical trials of stem cell treatments are underway around the world, the evidence base to support the medical use of stem cells remains limited. Therapies offered at clinics around the world generally have not received stringent regulatory oversight and have not been tested with rigorous trials. The IOM, the National Academy of Sciences, and the International Society for Stem Cell Research held a workshop to examine the global pattern of treatments and products being offered, the range of patient experiences, and options to maximize the well-being of patients, either by protecting them from dangerous or ineffective treatments or by steering them towards effective treatments.