okay. dxm isn't necessarily fatal in large doses, especially considering the fact that it takes quite a bit to put you in the red zone, and then a bit more to put you past that. something like the equivalent of 4+

z bottles of tussin max (generic name, taken to include cvs, rite aid, waltussin, robitussin). these all contain 15mg/5ml dextromethorphan hydrobromide, aka dxm. 237ml/bottle, 15mg/ml gives you 711mg dxm per

z bottle, so, yeah, it would take an insane amount of tussin to od on dxm. now, given the fact that after the first bottle or two of tussin you would probably be unable to chug any more due to the overwhelming nausea it would incite in you, you're pretty safe from od'ing on tussin. the same thing goes for things like drixoral and dexalone. you'd have to take about 85 of these to be at the od range stated by someone earlier in this thread. yeah, the day i see somebody down 85 pills within any amount of time for it to be noticeable is the day i give up dxm altogether. the only way for you to be able to od on dxm would be by buying pure dxm and pressing or capping it in extremely high doses yourself.
on to something about the effects of dxm. dxm hbr is an antitussive, or cough suppressant. it acts on the cough center of the medulla, also known as the "lizard brain." this is the part of your brain that also controls balance and other important fundamentals of functioning in society proper. what i believe happens when you robotrip is that the dxm not only "numbs" the cough center in the medulla, but spreads to other parts of said grey matter. that would explain why people can't walk straight, if at all, when they're dexing. i'm still in the process of reading up on the medulla's functions and just exactly how dxm works, so this may be just pointless rambling. but at least it may spark someone else to go and learn something that they can blow someone's mind with.
and to post something about the original post in this thread...while humans are awake, there is a chemical that builds up in our body. i can't remember what it's called right now, so i'll have to get back on that later. it seems that larger amounts of this chemical are found in people who have been awake for long periods of time (go figure). so, maybe a buildup of this chemical is what causes people to "trip" after being awake for days on end. anyone have any solid info on this? seems that this chemical is what makes us tired, and it dissipates as we sleep. very odd behaviour. still, it could be a toxin or a psychoactive, i'm still unsure. i'm going to go a bit more in depth and maybe i'll find something interesting to share. maybe, once i find out what the hell that chemical was called, it will be possible to find it in some plant or something. hell, maybe there's some way to synth it. i don't really know as of now. but, if it can be done, i'll probably be the crazy mofo that tries it and is completely, utterly insane for the rest of my days. all for the sake of knowledge.
have fun when you trip for the first time. make sure you're somewhere comfortable, and it'll be a great experience. and i am going to agree with whoever said to try alcohol and/or mary jane before stepping up to the real psychs. whichever you do first, walk or crawl, i'm sure you'll enjoy it.