Research into the biological properties and clinical potential of stem cells has spurred strong public investment,industry development,media coverage,and patient interest in recent years.To date,however,few clinical applications of demonstrated safety and efficacy have been developed with the exception of uses of hematopoietic stem cells in the treatment of diseases of the blood and immune systems.This lack of an evidence basis notwithstanding,hundreds of companies and private clinics around the world now sell putative stem cell treatments for an enormously broad range of medical and quality-of-life conditions.This represents a major challenge for legitimate scientists working in the field,for authorities seeking to protect their constituencies,and for patients and consumers targeted by such companies’ marketing strategies.In this review,I provide an overview of the global industry in pseudomedical stem cell treatments,with an investigation of claims in a single disease area (amyotrophic lateral sclerosis),and make recommendations for the introduction and enforcement of appropriate regulatory responses to this problem.