Okay, I just bought, and chugged, Robitussin Maximum Strength Cold and Cough.

Active Ingredients:
- DXM: 15mg per 5mL

It was 4 oz, so I got about 90 mg. I hope SOMETHING happens. The most I've ever done with DXM is taking 2 capfuls, and I really don't get that fucked up. But...this is 3x more than anything I've done so, let's see. ^_^