By good stuff do you mean the healthy bacteria. The intestinal flora? I always thought, I must take care of my intestinal flora. But it doesnt work that way I guess. If we are clean inside, our bodies can generate healthy bacteria in no time. Artificial injestion of pro-biotics is not needed. Trust me, I used to take a lot of pro-biotics to improve my intestinal flora, but it did not help me with my digestion issues.
Andreas Morithz has also mentioned that injestions of probiotics is not needed if we are clean inside...
After I started cleansing, I started seeing improvements. I have read that SWF, sends the salt water down the GI tract to give a quick and thourough washing. The blood does not pick the salt, and the kidneys do not pick the water. Hence no harm is done. It is even superior to Enemas and Colonics.