I can only speak from my own experience but for me it is normal for the colour, frequency and even consistncy of my BM's to change whilst cleansing. I have also had the dark bits coming away - I dont know what it is but I guess its better out than in! Since helping my liver my stools are darker in colour (die-off for me turns my stools darker), plus the increase in bile helps darken the stool. Light stools are not good.