It has been banned in the Olympics, big-league football and intercollegiate sports. The armed forces have pulled it from their commissaries. Canada called it "a serious risk" and recalled it last year.
So why is ephedra still on store shelves in the United States?
The reason, say some critics of the herbal stimulant, is that Congress in 1994 set up an unworkable system for regulating dietary supplements.
Before a company can sell a drug or medical device, it must prove to the Food and Drug Administration that its product is safe and effective. But with ephedra and other supplements, the burden is on the FDA to show that the product is unsafe before taking regulatory action.
"It's almost impossible for the government to prove that a product is unsafe," said Sen. Richard Durbin (D-Ill.), who said he is working on an overhaul of the Dietary Supplement Health and Education Act, which laid out the rules for regulating supplements. He said the law creates "a burden that they'll never meet."
"Since the FDA has a limited budget and limited staff for studying dietary supplements, their opportunity to prove that [a supplement] is dangerous is extremely limited," said Thomas J. Moore, a health policy analyst at George Washington University. Some critics of the agency see a problem not only with the burdens set by the law, but with the FDA's willingness to use the authority it was granted.
Under the law, the agency can ban the sale of products that pose "an imminent hazard to public health" or "a significant or unreasonable risk of illness" when used at the recommended dosage.
Dr. Arthur P. Grollman, a pharmaceuticals expert at the State University of New York at Stony Brook, said he had no doubt that evidence existed to show ephedra posed an "unreasonable risk" to consumers. Sold as a weight-loss aid and energy booster, the supplement raises heart rates and constricts blood vessels.
"This is one of the best-established relationships I've seen in 30 years of being a clinical pharmacologist, the relationship between ephedra use and cardiac arrhythmias, hemorrhagic stroke ... and sudden death," Grollman said. "It couldn't be more clear.
"If they can't do it with ephedra," he said, referring to a ban, "then they will be able to do it with nothing."
Dr. Sidney Wolfe, director of Public Citizen's Health Research Group, a consumer advocacy organization, said the FDA was "cowardly" for refusing to ban ephedra products. "I don't believe anyone in the industry thinks the 'unreasonable risk' standard has not been met," said Wolfe, whose group has petitioned the FDA for a ban.
The supplement industry says ephedra is safe when taken as directed and that the 1994 law gives the FDA adequate authority to remove dangerous supplements from the market.
Federal health officials said Friday that they wanted additional data on the effects of ephedra, and they asked for public comment on its safety. They also released a Rand Corp. study that cited "numerous gaps" in the scientific literature on the safety and effectiveness of ephedra.
They said they believed that ephedra products should carry warning labels and that they may propose a ban eventually. "The standard for regulating the safety of dietary supplements is largely untested, but we are committed to finding the right public health solution," said FDA Commissioner Mark McClellan.
Grollman and others say the FDA has credible data, which it solicited. At the agency's request, researchers at UC San Francisco reviewed 140 "adverse event reports" on ephedra provided by the FDA, including reports of deaths and permanent disabilities. The researchers concluded that 43 of the events were likely caused by the supplement.
The study was published in 2000 in the New England Journal of Medicine, which released it earlier than originally scheduled because of its implications for public health.
A later study of adverse event reports, published in the Mayo Clinic Proceedings, found serious problems even when people took ephedra at recommended dosages, Grollman said.
The supplement industry has discounted the studies, saying that adverse event reports are unreliable. These reports, usually made by consumers to the FDA, are subjective and include information of varying quality, the industry says in arguing that they should not be the basis of regulation.
Some people familiar with FDA matters say the agency's caution is rooted in experience.
In 1997, the FDA proposed dosage limitations on ephedra products. A 1999 report from the General Accounting Office, the investigative agency for Congress, criticized the analysis the FDA used in calling for the regulation.
The FDA later backed away from its proposal.
Wolfe asserted that the FDA's caution was because of political pressure from the nutritional and dietary supplement industry, which made almost $2.4 million in political contributions in the 2000 election cycle, the last one for which reporting is complete.
"The health and science and law all forcefully mandate a ban, and the fact that it's not happening means something other than the law and science and medicine are operating here -- and it's political pressure," Wolfe said.