Medicine has evolved a lot; treatments cure you fighting against disease, although these treatments aren't sure at all, because they cause side effects as kidney, liver and cells damage, body deterioration, etc.
Natural medicine can also produce other effects, but these effects are more controllable and there isn't so much danger.
I think the worst danger is that you can meet people who use plants without knowing anything about them and they offer you to treat your illness.
To sum up, I reckon alternative medicine isn't as true as traditional medicine, even though I don't think it is false. So, I respect people who use it.