SIBO (small intestinal bacterial overgrowth) is an "abnormally large numbers of bacteria present in the small intestine, leading to impairment of digestion and absorption" (Dr. Mark Pimentel, MD, of Cedars-Sinai). One common misconception is dysbiosis (overgrowth of bad bacteria and/or yeast with lack of good bacteria present) causes SIBO, but in fact, dysbiosis is the result of SIBO.