In all reality.. it depends on the strength of the dye. Some dyes that I have come into contact with only need to briefly touch an area in order to stain it an extremely bright (and rather hard to remove) colour. We're rather ignorant as to where the meth we ingest (in whatever way you choose) actually touches our body, as it doesnt leave any colour marks. However I could see a pright pink dye being rather embarassing as it would probably end up coating your nostrils, covering your hands, your lips and mouth.. and imagine being in a club where it glows!
Anyway, I wouldnt be a big fan of ingesting something that has that effect.. even if you could conceal the dye (ie, eating it in caps). I dont care about the end products colour.. but ingesting bright fluorescent pink dye just doesnt sound all that healthy.
stace.