Capitalizing on the hype surrounding stem cell research, numerous clinics around the world offer “stem cell therapies” for a variety of medical conditions. Despite questions about the safety and efficacy of these interventions, anecdotal evidence suggests a relatively large number of patients are traveling to receive these unproven treatments — a practice called “stem cell tourism.” Because these unproven treatments pose risks to individual patients and to legitimate translational stem cell research, stem cell tourism has generated substantial policy concern and inspired attempts to reduce these risks through the development of guidelines for patients and medical practitioners. This paper examines the roles and responsibilities of physicians in patients' home countries with respect to patients' decisions to try unproven stem cell therapies abroad. Specifically, it examines professional guidance from two organizations — the American Medical Association and the International Society for Stem Cell Research — and assesses physicians' professional and legal obligations to patients considering unproven stem cell therapies. Then, drawing on qualitative interviews conducted with patients who traveled abroad for unproven stem cell treatments, it explores the roles that physicians actually play in patients' decisions and compares these actual roles with their professional and legal responsibilities. The paper concludes with a discussion of strategies to help improve the guidance physicians provide to patients considering unproven treatments.