Normally, unless a supplement is proven to dangerous 100% of the time, I'm ok with it; it's usually un-informed people making bad decisions about what they are putting into their own bodies.
But in the case of ephedrine, I can easily say stay the heck away from it.
In my early 20's, when the ECA stack was just becoming popular, I got a severe nosebleed while doing squats one day. I'm talking a gusher. This was very disturbing because:
I never get nosebleeds. I've been kicked, kneed, elbowed, punched and even head-butted in the nose. Never once did it bleed.
Needless to say, I stopped taking ephedrine that day, for that very reason.
Does it work? Yes, it's proven and effective fat burner, due to the increase in metabolic rate; I had some of my most intense workouts ever while on it.
Is it safe? Even though the jury is still out on that, and it's still legal, I'd say it's leaning towards the dangerous side.
All I know is that it's sure as hell not worth a massive stroke.
"You do not truly know someone until you fight them."
- Seraph, The Matrix Reloaded