Although exercise-induced bronchoconstriction (EIB) (often referred to as exercise-induced asthma) is well-known, exercise-induced anaphylaxis (EIAx) is less well-known yet potentially much more serious. A 28-year-old female athlete who had three episodes of EIAx is described. The exact mechanisms involved in EIAx are unknown, but a release of mediators including histamine appears to be a common underlying factor. Once anaphylaxis has been triggered, administration of epinephrine is the most effective treatment. For prevention, food allergies should be identified and the appropriate foods removed from the diet. EIAx-prone people should not exercise for at least 2 h following ingestion of food or alcohol; these people should also be supplied with epinephrine self-injection kits and advised to exercise on a buddy system, especially in wilderness areas. The possible role of opioid antagonists is as yet unclear.