At least one of us is confused.

Possibly me. I'm provisionally retracting that; my reasoning was that if eating red things, drinking from red cups etc. reliably increased alertness someone would have noticed and we would be exploiting this effect, not looking for it within the restricted context of eating a pill. However, I'm now remembering that there is just such a claim, called the "red room effect", which I have no particular reason to disbelieve.