There are different protocols, yours is Clark. Andreas Moritz says first to clean the liver and colon, again to get things flowing to be able to get the dead parasites out, in case you have them. If you have constipation you will get all these corpses sitting in your body and would clog the liver even more. The liver produces bile what you need for digestion.
He also says if you keep your colon and liver clean the parasites have no place to live, but most people seem to do parasite cleanses. I did it after 2 years I was curious, nothing there.
It is important to get your bowels going (but you need a clean liver for that). The most simple way is to take 1 tsp of ES in the morning (with warm water when you get up), you can do this up to 3 weeks. After a week if you feel that you are moving do the liverflush and skip the ES. As part of the liverflush you will use more ES and that will clean you out :)
Here is an interesting link, read the whole thread so you can get different people's views. //www.curezone.org/forums/m.asp?f=337&i=12699