You can trip on DXM, yes. What's harmful is if there are other active ingredients in what you're taking. Zicam max is probably the only thing around aside from Robitussen. Mostly, people take Delsym or Coricidin. The first is syrup and the second is pills. Coriciden has an antihistemine in it, which can be dangerous in large amounts, however, if you take ten pills, that's not enough to do damage.