The Bush administration on Tuesday banned the popular herbal weight-loss supplement ephedra (search) because of health concerns.
"I can report to you that we're about to ban dietary supplements containing ephedra," Thompson said during the press conference. "For too long, dietary supplements containing ephedra and alkaloids … they are simply too risky to be used."
Thompson said that, based on the "best possible scientific evidence" and more than 16,000 incident reports saying ephedra caused adverse effects, the government deduced the product presents an "unreasonable risk to the public health."
Ephedra, also known as Ma huang, Chinese Ephedra and epitonin, poses health hazards ranging from high blood pressure, irregular heartbeat, nerve damage, injury, insomnia, tremors and headaches to seizures, heart attack, stroke and death, the FDA says.
Ephedra has been linked to as many as 100 deaths, officials have said.
McClellan said his agency was concerned about young people and athletes looking to ephedra to boost their performance. Use of the supplement has led to serious health effects, he said.
"We're sending a strong and clear signal" that such products should come off the market, McClellan said.
The rule will go into effect in 60 days "and have the practical effect" of banning ephedra, he said.
"Ephedra raises your blood pressure and stresses your system," McClellan said. "There are far better, safer ways, to get in shape."
The ban is likely to be met with litigation from manufacturers who dispute the agency's assertion that ephedra is a health risk.
The FDA will issue a consumer alert about products containing ephedra, "warning everyone of the dangers they pose," Thompson said, and will send letters to 62 product manufacturers saying they must stop selling ephedra-laden products as soon as the rule takes effect.
"Today's actions tells consumers that the time to stop using these products is now," Thompson said.
Under current law, pharmaceutical companies have to prove their products' safety and efficacy before they can receive FDA approval; but for supplements, the FDA has to prove the products unsafe to prevent them from hitting store shelves.
"It's a completely different burden of responsibility but that's the law," Thompson said.
Ephedra, which has also been used by many athletes to enhance performance, is believed to have killed 23-year-old Baltimore Orioles baseball player Steve Bechler last February. Bechler died during spring training while trying to lose weight. Toxicology tests showed ephedra was in his system.
Ernie Bechler, Steve's father in Medford, Ore., said he was awakened by a phone call around 6 a.m. local time with word of the decision.
"It's the only thing that could make my wife and I be happy," he said. "Nothing else could have done what this is doing. I mean to get this off the market and to save other peoples' lives is just amazing to us."
Ernie Bechler testified in Congress, urging a ban. "That's the last thing I said: 'Please don't let my son die in vain."'
The government ban, one of the first involving a dietary supplement, comes after Thompson urged Congress this summer to require manufacturers to acknowledge potential side effects and to rewrite a law that rolled back dietary-supplement regulations.
Congress has gathered testimony from families of people who are believed to have died from ephedra's side effects.
Executives of several companies that make ephedra-based products said studies have proven that they are safe when used properly.
"Anyone who has read our label knows that we go to great lengths to inform our customers about the proper use of our products," said Russell Schreck, CEO of San Diego-based nutritional supplement-maker Metabolife International.
"We make it quite clear on our label that the ephedra products are not to be sold or used by minors and that customers with certain pre-existing medical conditions should 'consult a physician before product use.'"
Scientists have said it's impossible to prove whether ephedra is safe, because studies screen out participants who have health problems -- the people most likely to be hurt by the products.
Three states -- New York, Illinois and California -- have passed their own ephedra bans; use has been banned in professional football, college athletics and minor-league baseball, and several retail chains, including supplement giant General Nutrition Centers, recently quit selling it, too.
"It's a dead product, and unfortunately it has become a dead product over the backs of a lot of dead people when the FDA could have acted before," said Dr. Sidney Wolfe of the consumer advocacy group Public Citizen (search), which petitioned the government for a ban in 2001.
Wolfe urged remaining manufacturers to recall all ephedra-containing products still on store shelves. For any future ephedra-linked injuries, "there's going to be hell to pay in terms of increased liability on the part of the companies that are allowing it to be sold," he said.
The supplement industry's Council for Responsible Nutrition said it didn't oppose a ban, noting that very few companies still make the stimulant -- its members who once did no longer do so.
"We think the reputable players have found so much controversy and difficulty in this marketplace that they've decided to get out of it," said CRN's John Hathcock. "We recognize the controversy is a cloud over our whole industry."
The General Accounting Office, Congress' investigative arm, looked into the issue and found many people who reported problems had followed the label's instructions.
The FDA had proposed warning labels and dosage limits for dietary supplements with ephedra back in 1997, but then withdrew the proposal after complaints from the industry and members of Congress.
The Associated Press contributed to this report.