Ephedrine is one of a few compounds in the Ephedra Alkaloids genus of plants. While Ephedra Extracts has been taken from the U.S. nutritional supplement market, its active component ephedrine can nevertheless be present in some over-the-counter and prescription medicines, such as for example those used to take care of asthma. Ephedrine's effects mimic those of adrenaline -- the hormone that controls the body's "fight or flight" reaction.