英语时差:麻黄减肥禁令
In the United States, the government is acting to ban the sale of ephedra as a product to help people lose weight. Ephedra is a plant that contains ephedrine and pseudoephedrine. These substances can increase a person's energy level and cause weight loss. However, officials warn that ephedra also raises blood pressure. Ephedra has been linked to heart attacks, strokes, seizures and deaths. The secretary of Health and Human Services announced the ban. Tommy Thompson urged people to stop using ephedra even before the ban takes effect. He said he did not want to delay the announcement, because people often try to lose weight at the start of a new year. The market has grown sharply for herbal products known as dietary supplements. Companies do not have to prove them safe and effective the way drug makers do. In nineteen-ninety-four, Congress limited the ability of the Food and Drug Administration to take action against supplements. This is the first ban since then. The ban will not include the version of ephedra used in medicines to treat breathing infections. Ephedra has long been used for this purpose as a traditional medicine in China, where the plant is called ma huang.
