Since my freshman year in college (a small liberal arts college in northern Vermont), I've been fascinated with the correlation between the ingestion of food-coloring and the color of the poop produced. Lest you think I'm fabricating, here's the background:

The year was 1996. I was a biochem major at St. Michael's College in Winooski, Vermont. I had consumed copious quantities of Purplesaurus Rex Kool-aid in a one night time frame. A few hours later, I pooped. It was green. Bright green. I was fascinated, and called as many of my floor-mates as would come into the stall to marvel at the miracle of the "not brown, not bloody shit".

I was a bit of a celeb for a while, until others replicated my "experiment". Similar results ensued, with me being notified of each event via e-mail. So, a craze started.

As the progenitor of the new species of poo, I was caught in the middle. Research spread far and wide; of a campus of 2700 students, I was receiving up to 45 e-mails a day from poopexplorers.

Anyway, enough drivel. Here's the science:

The dye used in purplesaurus Rex is FDA Blue #5, and dye-lake red. Turns out that when metabolized in sufficient quantity, the blue dye combines with bile, and forms a brilliant green. The red, absorbing at a 595nm spectrum, is harmlessly eliminated.

What matters is quantity. I consumed 6 liters of the Kool-aid in the night in question (sans alcohol, that comes later). I set up a study in the dorm, with people consuming anywhere from (1) 250mL glass of the stuff (approximately (1) 8oz glass) to the maximum tested so far, 6L. The experiment was structured on a single-blind study (won't get FDA approval, but sufficient), with only myself knowing what each was consuming.

How did the experiment come into being, you might ask? Well, I campaigned for 24 "volunteers" (the first consuming 1 glass, the last consuming 24 glasses). How did they not know what they were drinking? Well, since it was only single-blind, they essentially did -- though all were required to drink 6L of fluid total, and ordered not to defecate at all in the 6 hours of the experiment.

Example: Subject 1 received 250mL of the subjected test substance, and 5.75L of water. Subject 2 received 500mL of the stuff and 5.5L of water.

Everyone was agreeable at first, but soon dissention reigned prime. But order was maintained. After 6 hours, orders were given to poop, supervised (more or less). Since I had unrestricted access to the chem and bio labs, samples of each "extrusion" were taken, in the amount of 2g.

The results were heartening. I plan on getting a PhD (which, in this instance would probably mean, "PUSH HARDER, DUMMY!") on this someday, so I won't post my final data, just enough to give an idea:

• Subject 1: 250mL Purplesaurus Rex with 5750mL water:
  Stool, firm and brown. Spectrophotometer reading: normal.
  
• Subject 12: 3000mL Purplesaurus Rex with 3000mL water:
  Stool, firm(ish) and green(ish). Spec reading 550nm (definitely Green...just not GREEN)
  
• Subject 24: 6000mL Purplesaurus Rex with 0mL water:
  Stool, Firm(ish) and Green, resplendent of original test subject (me). Spec reading, 535nm. Definition of GREEN confirmed.
  

Further experiments considered fruit punch (mostly synthetic, only 2.5% fruit juice), Hi-C of various persuasions, and various and sundry other store-bought concoctions.

If you're interested in my results, let me know...I'll gladly share them for the good of society.

-- Dave J [1]