It is my understanding that because some persons have had problems with Gallstones while on The Master Cleanse that they should do a Liver Flush before doing the Master cleanse.
it says, "The Clinic suggests 7-10 days on the Master Cleanse, followed by a Liver Cleanse. On the last two days of the lemonade fast, drink organic apple juice alternating with the lemonade (to soften gall stones). Before bed, drink 1/2 cup fresh- squeezed lemon juice with 1/2 cup olive oil. Next morning, have a colonic."
it says, "Since this diet is very low on calories, one potential side effect is rapid weight loss which could lead to the formation of gallstones. People who are suffering from diabetes, cancer, anemia and Gallstones should not use this detoxification method." Which is why if you think you might be prone to Gallstones you should do a liver/gallstone cleanse first.