Dr. David O. Young, author of pH Miracle Diet talks a lot about doing this type of flush in the morning but drinking an 8 oz glass of purified water and 2 ts of sea salt. After drinking this sea water (ugh) you'll need to quench your thirst with at least a liter or two of purified water. I tried it and boy! it gives your intestines a REAL workout without the aid of herbal laxatives. If anyone decides to do this, I'd give yourself at least three hours before leaving the house.
It does wonders for your skin. Similar to colonics but costs $60 less.