ephedra
n. a bushy shrub (Ephedra sinica), known to Chinese herbalists as ma huang, that is indigenous to arid regions of the world, particularly Mongolia and northern China. The leaves contain significant amounts of the alkaloid stimulants ephedrine and pseudoephedrine and are traditionally made into a beverage. Both ephedrine and pseudoephedrine are strong sympathomimetic agents and therefore increase blood pressure, alertness, and anxiety, as well as causing peripheral symptoms of sympathetic activity (e.g., tremor, sweating). These agents also relax smooth muscle; hence, the plant and its active components have often been used as a remedy for asthma or other respiratory complaints. In addition, ephedra has been combined into many dietary supplements that are reputed to aid weight loss, increase energy, and enhance athletic performance. There is, however, little evidence of ephedra’s effectiveness for these uses except for modest,
short-term weight loss without any clear health benefit. It is toxic and potentially fatal, particularly in high doses or when combined with other stimulants, such as caffeine; reported adverse events include headaches, insomnia, rapid or irregular heartbeat, nerve damage, muscle injury, psychosis, memory loss, heart attack, stroke, seizure, and death. In 2004, the U.S. Food and Drug Administration banned the sale of products containing ephedra, the first U.S. government ban of a dietary supplement.