Recent surveys have found that most families treat their affected children with one or more forms of complementary and alternative medicine (CAM) in an effort to improve outcomes. To date, studies that rigorously evaluate the scientific evidence for safety and efficacy have been published for only four CAM therapies for autism spectrum disorders (ASD), and there is no readily accessible source of information to inform families about the potential risks and benefits of over 50 reported CAM therapies used in this disorder. This project will determine and report on the safety and efficacy of CAM therapies in three ways. First, a survey will be conducted of parental perceptions of efficacy, cost, and time devoted to each intervention. Second, systematic literature reviews will evaluate all prior published evidence for each CAM therapy and make the information available on an open-access website to families and providers. Third, pilot studies will be initiated to more clearly determine the potential mechanism of action of the most promising CAM therapies.