600 mg of caffeine is really getting up there to the limit though...I'm not sure what the fatal amount is, but it's a LOT A LOT A LOT...more than 600 mg...I would wig out if I took that much caffeine, though....I don't like it...You'd probably get nervous and have a "bad trip" or at least get some bad anxiety if you took it with any hallucinogen. People reccomend xanax or other sedative while doing hallucinogens...less chance of anxiety, more calm, serene feeling.