According to my pharmacist, Centrum's being protein-based makes it difficult for most people's systems to digest. The only way for the pills to have much, if any, legitimate effect, they must be taken by those with extremely high-protein diets. Essentially, it ends up just cleaning out the urinary tract.

There are plenty of other non-liquid supplements that do not have this problem. My pharmacist said i shouldn't have a problem with One-a-Day, so that's what i use.

As for the septic tank thing, i don't know anything about it. Sounds a little extreme.