Some random Googling:
The Food and Drug Administration banned the weight-loss supplement ephedra as of April 2004, but you might not know that if you hang out on the Internet. Ephedra Outlet touts "Ripped Ma Huang Ephedra Diet Pills”; BuyEphedraOnline.com ("Your #1 Source for Ephedra Products") offers Trimethylene with "10 mg ephedra." Several sites sell Ephedra 5, "the only clinically proven, legal Ephedra supplement in the United States."
What gives? Turns out the FDA banned alkaloids of ephedrine, found mainly in the stem of the ephedra sinica species. It's the chemical presumably responsible for weight loss but also for boosting heart rate and blood pressure. Adverse effects included heart attacks, strokes, seizures, and even death.
Current pitches wriggle out of the rule by claiming to sell extracts from species of ephedra (viridis and others) that contain little or no ephedrine. Those "legal" ephedras aren't likely to pose dangers—or do much else, says Bill J. Gurley, Ph.D., a professor of pharmaceutical sciences in the College of Pharmacy at the University of Arkansas for Medical Sciences.
An FDA spokeswoman confirmed that the products are legal as long as they don't contain alkaloids of ephedrine. But any sites selling ephedra with ephedrine (we found a few claiming to do that) are doing so illegally, even if the products are left over from before the ban.