Mickey,
For most products it is probably not necessary to wait much longer than it takes to stop feeling any affects from the previous product. This is especially true if you are switching to an oxygen-based colon cleanser like Oxy-Powder. If you are considering switching from an herbal cleanser to another herbal cleanser, I would probably wait for a longer period of time, especially if you have been using the first product for a while. If you are considering using a herbal-laxative based product, I would recommend reading the following article:
www.colon-cleanse-constipation.com/dang ... anser.html.