No cramping like that experienced with herbal laxatives...HH doesn't contain any. Occasionally people will have some cramping when a large piece of mucoid plaque breaks off and is winding through the pipes...but the cramp passes as soon as the gunk does! The bloating can also cause some cramping...and as Birdie indicated...it can be rather foul! But it all gets better as the cleanse progresses...and when you're finished your tummy will be flatter than ever!