It Also Gets the "Brown" Out
So I was watching a re-run of a re-run of Conan late last night with Amy Sedaris, and she said a certain substance (which was bleeped out) when mixed with a drink can give you explosive diarrhea.
The substance: Visine.
How does it work? This incredibly detailed and well-read blog comment I found might help explain it.
The best way to find out: Try it on your enemies (or friends, but that's just wrong).