I believe the threshold dose is around 30mg, or half of it I can't remember. This is why erowid is indispensable when wantin to take a new drug, never ever trust word of mouth on dosage info and effects (especially off the fuckin internet). Cuz message boards tend to attract some decent folk, but then crackheads like me come along and tell ya u should take 17 boxes of C+C IF you wanna trip real hardcore, then you're wakin up in hospital, havin to explain ure situation and how you came about ure current condition with a snotty nosed, probly overweight nurse shovin tubes down various oraphices (doin lots of tut's and 'u should know better' bla bla bla) and this is never a good settin for trippin in. but you went wrong cuz u took an inactive dose man, you wanna be aiming sumwhere in between 200mg-700mg dependin on how hard you wanna disassociate ureself. And whatever u do, try and ensure that you got a syrup or tablets that have only DXM as the active constituent/ingredient, cuz those cold remedies contain a lot of other more toxic stuff, rangin from givin u the shits, guafenisen sp?, or serious liver damage, paracetemol/acetimophen if your a yank.
Happy Trippin