Our body contains inside and on the surface more bacteria and viruses than the total number of our cells. This amounts to an average of 1 kg microorganisms per individual. Each person has his/her own profile of microorganisms. Some of these bacteria are in vast minority but could increase in number and cause diseases, example: Helicobacter pillory.The majority of these bacteria have a positive role in the metabolism of food and body protection
When talking about flora in the context of the human body, the term refers to bacteria, yeast and other fungi. Those are help to metabolized food and body protection.