We have good bacteria and bad bacteria. When the good bacteria flora of instinales are quite numerous: balance comes naturally (stress, alcohol consumption, significant absorption of caffé or long use of Antibiotics prevents these good bacteria to grow). I fully agree that we must first kill the bad bacteria and then we must consume natural yoghurt (because they contain L-Casei "lactic ferment") and also get rid of stress. The balance is recreated naturally because the good bacteria are quite numerous in the intestinal flora.
that's why I think he should also be caused by stress.