its true what your friend says...too much of a good thing and your depleating your body of it's own natural defenses! i learned the hard way back....i ended up with a serious yeast infection in the bowels because i washed the natural occuring good bacteria out!
there is nothing wrong with cleansing and flushes, just not too many! my np says a good flush (he call both flushing and cleanses the same) once a year as long as your diet remains healthy and consistant!
yogurt can help.