Small intestinal bacterial overgrowth (SIBO) is a form of dysbiosis (or abnormal gut microbiota) characterized by an excessive amount of bacteria in the small intestine, sometimes due to elevations in bacteria that are usually found only in the large intestine. It is considered both a clinical syndrome and a potential mechanism that could contribute to the progression of other diseases.[1]
Normally, the environment of the small intestine — including the acidity, oxygen level, motility (the ability of muscles to contract), and immune cells — control microbial growth. If this environment is modified by acid-suppressing medications, surgery, or disease, microbes can rapidly divide and take up residence in previously inhospitable areas of the small intestine, resulting in SIBO.[2]
