Small intestinal bacterial overgrowth (SIBO) is a disorder of excessive bacterial growth in the small intestine. Patients with bacterial overgrowth typically develop symptoms including nausea, bloating, vomiting and diarrhea, which is caused by a number of mechanisms. Many of the symptoms are due to malabsorption of nutrients due to the effects of bacteria which either metabolize nutrients or cause inflammation of the small bowel, impairing absorption. A simple diagnosis of SIBO is with a breath test. SIBO is typically treated with antibiotics.