You should get the kind with only DeXtroMethorphan as the active ingrediant, if you're going for syup you probably want the robitussin maximum strength cough or generic equivilants as that has the most per bottle(354mg per 4oz). There are also gels(300mg a bottle) that are a bit easier to take at first but seem to cause a bit more side effects for some, as well as the new zicam sprays that have a conentrated amount(300, 400, 540) in about half a shot of fairly horrible tasting liquid.
As always
Erowid is your friend and has most of the information you could need, especially the semi-famous(in the sub-culture at least)
DXM FAQ.
If anyone has done PCP or Ketamine(or to a lesser extent n2o) it is relatable to that, as it is in the same class of drugs, dissasosiative anestetic. In low doses it is more recreational, feeling like a mix of marijuana alcohol and mdma while in higher doses it's relatable to a 6 hour K-Hole, with full on psychedelic internal trips that alot of people think is more intense then acid.
I know some people might look at cough syrup and automatically not see it as a "real" drug, but believe me it is. When new even a small 300mg dose can blow your mind, especially with binaural beats playing. Just remember heroin used to be a cough syrup before it was replaced with other opiates before it was replaced with DXM.
As for risks, anti-drug propaganda has started on the drug and there is alot of stuff out there saying how it will cause brain damage and organ damage, when there is no evidence of this at all. Taking large doses multiple times days in a row could be particularly hard on the brain/body but there have been numerous people who have dosed that way with no problems(not me, I've always kept my use at least a week a part). The only thing that is semi-credible is the stress caused by mass amounts of glucose if taking syrups(zicam really is the closest to pure/extract, providing the cleanest feeling trips).
Psychological risks are very real though, as is true with most psycedelics(though this one does seem to be at least slightly hard on the body unlike the traditional ones like LSD or Mushrooms). Many things can happen unexpectedly on higher doses, such as spontaneous memory recall, complex delusions, hallucinations, out-of-body experiences, near-death experiences, and perceived contact with spiritual or alien entities. You need to be pretty stable and grounded before you can handle these things(from the FAQ and totally true).
Lingering dissaosisation is normal(in fact the day after a large dose usually produces an afterglow, instead of a hangover, where you still feel somewhat altered(in a good way for most) even if you remain completely sober), though some may perceive that as a hinderence to normal function. Most common side effects are nausea/vomiting(these two are mostly mental due to methods of ingestion, work very hard not to vomit the first few doses and you shouldn't have to worry about it later on, give in and purge and you may find yourself gagging at the thought of syrup or gels down the line) robo walk(just the name for dxm's own personal brand of balance issues, with the dissasosiation its hard to control movement at first) and robo itch(shouldn't have to explain that... gels seem to give it more for most, on higher doses it's no fun at all(if u can actually feel it), basically just feels like your skin is on fire.
