I've done various types of cleansing from master clense to full blown (no pun intended) colonics and honestly, I dont think we are as toxic as we are led to believe.
Unless you're living next to a sewer, drinking infested water, have disfunctioning kidneys & liver, and eating fast food every day for the last 10 years, I really doubt we have such great levels of toxins that we need to do such drastic things to our body. Dont underestimate the power of your kidneys and liver.
My ayurvedic practitioner highly discourages such things, and reccomends that if you are indeed going to do a cleansing (juice, kitcharee or otherwise) to take a month to slowly get your body ready for the change and to go into and out of it carefully.
Be kind to your body.
(disclaimer, I'm not a doctor, check with your MD before proceeding)