Unfortunately that is one of the longest running scams ever. Ask any doctor who has taken a scope and looked around the colon. It's healthy, and pink. No where in there can you hide a corn flake (that was the old sales pitch... "I've seen 20 year old corn flakes in people's colons!).

Here's a picture of the inside of a colon looks pretty pink, slippery as all get out. Like a giant slide.

http://www.gihealth.com/html/test/drfuscos_colon.html (click on the drawing of the colon to see the various parts)