• The large bowel is the home of trillions of bacteria which are part of the normal flora. Here, they assist in regulating organisms, such as yeasts and bad bacteria which can normally be found in small amounts in a healthy gut; but run rampant in those which have had a lot of digestive disturbances
• The small bowel, in contrast, does not normally contain very many bacteria at all.

Typically, small amounts of bacteria are found in the intestine. If there is displacement of or a significant increase in the amount of bacteria, food and nutrients are not absorbed properly. Bacterial overgrowth can result from a slow transit of food through the bowels or from certain medications.