Bacteria living in the bowel has important roles such as helping to digest foods. Sometimes, interventions such as surgery and some medication can interfere with the normal processes of the bowel, which can lead to the bacteria multiplying, this is called ‘small bowel bacterial overgrowth’. When the bacteria in the small bowel reach high enough numbers they start to cause symptoms. These symptoms can include diarrhoea, Please click here for more information on small intestinal bacterial overgrowth, the symptoms this causes and how it is treated.