The Friendly Bacteria Inside each of us live vast numbers of bacteria without which we could not remain in good health. Before looking at the amazing things they do, reflect on just how many of them we house. There are several thousand billion in each person (more than all the cells in the body) divided into four hundred species, most of them living in the digestive tract. If they were all placed together the total weight of this "friendly" bacteria would come to nearly four pounds and, in fact, about a third of the fecal matter (water removed) which you pass consists of dead or viable bacteria. The Role of Friendly Bacteria in Health. These bacteria are not parasites. They do not just take up residence and do nothing in return, but perform many important functions in the body. We live in true symbiosis with them. As long as we provide them with a reasonable diet and as long as they remain in good health, these bacteria provide excellent service in return. However, n...