White Sage (aka California Coastal Sage, Giant Sage) is a highly medicinal plant. It is the #1 item for smudging and is said to be excellent for purifying and driving away "things".

My main use for it has been if I get a runny nose. I make up a pot of strong sage tea and drink it a cup now and then during the day. It doesn't taste very good but it sure does keep you dry, and with no bad side effects.

I don't think you can get high off of the smoke, but then I haven't been intensely exposed to the smoke - most smudging ceremonies I've participated in have been in relatively drafty environs (yurts and tepees). I doubt it used up much of your O2 though.

As a comparison of power, last time I got a badly runny nose I was out of white sage and brewed up several strong pots of my fresh garden sage. I drank lots and lots of it and it had no effect whatever (but it tasted better than white sage).

The best way to find out how much is enough is to try too much.

I do this a lot in cooking but try to go real easy on how much too much to try