http://my.webmd.com/content/article/1671.52406
Ephedra can cause heart complications, high blood pressure, seizures, strokes, even death, especially when combined with other stimulants like caffeine, guarana, and ginseng -- which are also common ingredients in these drinks. In the early 1980s, the FDA banned pills combining ephedra and caffeine, but a 1994 law removed dietary supplements from FDA control.
Although side effects to supplements do not have to be reported, about 800-1,200 serious reactions to ephedra have been -- less than 10% of the actual number, estimates Gurley. "I get calls literally every day from consumers, lawyers, and doctors describing bad reactions to ephedra," he says. "The public is not aware of the hidden dangers of these products."
When 15-20 different herbal extracts and "metabolic boosters" mix with ephedra and caffeine, side effects may be delayed or unpredictable, including insomnia, nervousness, headache, nausea, tremor, and heart palpitations. Some are serious or even fatal, like seizures, heart attack, kidney stones, and stroke.