yes, the Dextromathorphane (DXM) is what makes you trip, however, the makers of Robitussin added acetomenophen (tylenol) as a way to try to prevent people from robo-trippin, the idea was that people would OD on tylenol, get sick, and prevent too much DXM from being absorbed by the body.
And the idea that the alcohol in mouthwash is not safe is retarded. Yes there are multiple types of alcohol, some of which are not safe to drink, however these would not be used in a product such as mouthwash because no matter what, a small amount of it will be absorbed into your bloodstream through your mouth, and you're basically guaranteed to ingest some of it.
life is too short to have any regrets