Yeast infections are caused by an overgrowth of fungus in the vagina known as Candida. Reduction in IBS symptoms occurs following antibiotic therapy for small intestinal bacterial overgrowth. Small bowel bacterial overgrowth is a chronic condition. PPIs may predispose an individual to developing small intestinal bacterial overgrowth or fungal overgrowth. Systemic or metabolic disorders may lead to conditions allowing bacterial overgrowth as well. Elevation of serum folate is suggestive of small bowel bacterial overgrowth. It is especially useful where small intestinal bacterial overgrowth is involved. It has also been used to treat small intestinal bacterial overgrowth. Thus, detection of proximal bacterial overgrowth is critical. Lactulose is used as a test of small intestine bacterial overgrowth (SIBO). The condition that predisposed the patient to bacterial overgrowth should also be treated. This stage is useful for identifying patients with bacterial overgrowth syndrome. These patients were also negative when retested for bacterial overgrowth. Breath tests have been developed to test for bacterial overgrowth. It compares well to jejunal aspirates in making the diagnosis of bacterial overgrowth.