probiotics

They are known as commensal bacteria, which under normal circumstances cause no harm. Some are useful (these are the good bugs) but others have the potential to be very harmful. For example, the 'superbug' bacterium Clostridium difficile or the ulcer infector helicobacter pylori may live harmlessly within us, but can be the cause of serious illness if the gut environment gets out of balance and they multiply. The good bacteria, sometimes called 'friendly flora', are on our side. These live micro-organisms improve the balance of the intestinal soup by depriving polluting and dangerous bacteria of food and inhibiting their growth.