Three acronyms we mix up every day. SIBO is a measurable bacterial overgrowth, SIFO a fungal overgrowth, IBS a functional syndrome with no lesion. Symptoms overlap; tests and treatments differ. Three levels: the confusions, the tests that prove (or not), and the treatments with their pitfalls. Sources: peer-reviewed literature, Am J Gastroenterol, Aliment Pharmacol Ther, Curr Gastroenterol Rep. See our terms and conditions. The information shared here does not replace advice from a qualified health professional.