No, not a dumb question. :) It is best to use when fasting, when there's not a lot of fiber or meals in your intestines because it will interrupt digestion and that is rarely a good idea.

The only other time I recommend the SWF (Salt-Water-Flush) is the morning after a liver flush, if you have no other way to flush the stones out of the intestines. It can be safer than Epsom Salts .