[aussieshibe]

Ooooooohhhhhhhhhh.

I often thought: It seems like flushing first makes much of the cleaning product run right into the water rather than sticking to the bowl, but there must be a reason they say to do it.

[ixak]

No it's because urine contains ammonia, and if you mix bleach and ammonia you get a highly toxic chloramine gas that can literally kill you.