The active ingredient is not DMBromide, rather it is Dextromethorphan, an isomer of Levorphanol, a codeine analog. When taken in a high enough dosage, especially when combined with alcohol and MJ, it evokes a high undistinguishable from an acid or mushroom stone.
Currently the best commercial formulation is Contac CoughCaps. These tablets contain 30 mg DM each, come in packets of 10 or 20, and rest a hell of a lot easier on the stomach than does Robo.
Having tried both, I must recommend the Contac Caps if you are going to try DM, although you might want to reduce your dosages if you are going to trip more than one day at a time (after awhile the same dosage will make you puke (but that could also be attributed to the alcohol))
