Best colon cleansing method or products?

Are there any products, like at Trader Joes or Whole Foods Market that offer a good healthy way to cleanse your intestinal tract and detox your system? There is a lot of "products" out there, like on infomercials that cost hundreds of dollars. Im sure there is a better way then what they offer (and probably less expensive). Any tips or recommendations would be appreciated! Im not looking for drug detox system either. My wife came across some late night commercial and it looks like a gimmick, Im hoping to find something better, more reliable, from a reputable place too. Thanks for anything!