Pssh...you and your lies. Clearly you work for big pharma (in between kicking puppies and drinking blood of course.)
As I've mentioned before, you don't have blockage on the order of pounds in your colon, and it certainly isn't a common occurrence. A buildup of fecal matter (undigested meat, whatever you think it is) of only several ounces can be quite painful after 24 hours.
I'd agree there, the pipes in our sink probably have stuff left over from the day the building went up. That being said, sinks aren't really the perfect analogy for your intestines, they're too simple. You will excrete what's in your colon, or you will feel pain, it really is that simple.
Lets even assume, for a moment, that you don't necessarily excrete what's in there, and it could build up. It's not going anywhere, and it certainly isn't leaking toxins into the rest of your body. The colon's mucus(y) lining doesn't allow much besides water to be absorbed back into the body. Imagine if it was more permeable: the crazy amounts of bacteria that live in there would flood into the rest of your body and you'd almost certainly die of septic shock.