I am pretty new to this internal cleansing. My first Liver Flush was just two or three weeks ago. I don't know if it is a good idea to mix P&B with magnesium oxide, or not. I have been wondering the same thing! I am planning to follow the advise of more experienced cleansers such as Tracey. She has recently posted a lot of information on cleansing. Don't be discouraged - it is wonderful that you are working on your own health in this way.