There are dozens of different probiotic bacteria that are good for us. The two common groups are Lactobacillus and Bifidobacterium.
The complex mix of gut bacteria inside us is called gut flora or microbiota, and it contains hundreds of different types of microorganisms, including yeast and viruses.
Our gut bacteria, or gut flora has so much metabolic activity that it is referred to as the forgotten organ. The functions it performs include manufacturing of Vitamin K and Vitamin B, turning fibers into short-chain fats, strengthening of our gut wall and improving the immune system.