Ephedrine, ephedrine plus caffeine, and ephedra-containing dietary supplements with or without herbs containing caffeine all promote modest amounts of weight loss over the short term. There are no data regarding long-term effects on weight loss. Single-dose ephedrine plus caffeine has a modest effect on athletic performance. The available trials do not provide any evidence about ephedrine or ephedra-containing dietary supplements, as they are used by the general population, to enhance athletic performance. Use of ephedra or ephedrine plus caffeine is associated with an increased risk of gastrointestinal, psychiatric, and autonomic symptoms. The adverse event reports contain a sufficient number of cases of death, myocardial infarction, cerebrovascular accident, seizure, or serious psychiatric illness in young adults to warrant a hypothesis-testing study, such as a case-control study, to support or refute the hypothesis that consumption of ephedra or ephedrine may be causally related to these serious adverse events.