Don't be fooled by thinking salvia is just a "legal high". It can cause profound ego-loss for upwards of ten minutes. The history is that it is what native american shamans used to chew on to see visions.
A common experience is one in which people say "I forgot that I was something, then I realized I was something but I wasn't sure what that was." They then had to figure out the world again as the drug wore off. I think it's foolish to group something this psychologically powerful within the same group as something that "just gets you high" like alcohol or pot.
http://www.erowid.org/plants/salvia/salvia.shtml