That being the case, I'm not sure. I always assume that if someone has been eating a SAD (Standard American Diet) for any length of time, they need to do (a lot of) colon cleansing after they transition to a healthy, high-fiber diet. This is due to the reading I've done, and fact that I'm still eliminating a lot of old toxins after 14 years of colon and other cleansing. Does he eat a SAD?

If he takes the milk thistle and his colon can still eliminate okay, colon cleansing may not be a priority. Maybe it's something you and he can keep in mind for future reference. In any case, I hope you and he read "The Detox Book" so you'll have a sense of why detox is so important to one's health.

Tom