i still hold to the fact that if enough of any chemical/element (and just about everything from food and drugs to everything natural has some chemical/element in it) is in your blooodstream or system, you can od on it... od doesn't nessicarily mean you die, od is simply put, too much of it for you body to process it, and can be anything from a stomach ache to death... but i do have to say... there is no fucking way anyone could od on this shit by smoking it.... i would say... even if you made it to a 6th or 7 th hit (keeping in mind you basicly enter a whole new plane of existence at 2 or 3) you wouldn't even know wtf a bong was anymore, much less that you have salvia in it to smoke... so i'd say you're pretty much safe...